MC9S08GB60
MC9S08GB32
MC9S08GT60
MC9S08GT32
MC9S08GT16
Data Sheet
HCS08
Microcontrollers
MC9S08GB60/D
Rev. 2.3
12/2004
freescale.com
MC9S08GB/GT Data Sheet
Covers: MC9S08GB60
MC9S08GB32
MC9S08GT60
MC9S08GT32
MC9S08GT16
MC9S08GB60
Rev. 2.3
12/2004
Revision History
To provide the most up-to-date information, the revision of our documents on the World Wide Web will
be the most current. Your printed copy may be an earlier revision. To verify you have the latest information
available, refer to:
http://freescale.com
The following revision history table summarizes changes contained in this document.
Revision
Number
1.0 4/25/2003 Initial release
1.1 Electricals change, appendix A only
1.2 Electricals change, appendix A only
1.3 10/2/2003 Added module version table; clarifications
1.4 10/29/2003 Fixed typos and made corrections and clarifications
1.5 11/12/2003 Added 1-MHz I
2 2/10/2004
2.2 9/2/2004
2.3 12/01/2004
Revision
Date
Description of Changes
values to Electricals, appendix A
DD
Changed format of register names to enable reuse of code (from SCIBD to SCI1BD, even when
only one instance of a module on a chip)
Added new device: MC9S08GT16 to book. Added new 48-pin QFN package to book. BKGDPE
description in Section 5 — changed PTD0 to PTG0. Changed typo in CPU section that listed
MOV instruction as being 6 cycles instead of 5 (Table 8-2).
Format to Freescale look-and-feel; Clarified RTI clock sources and other changes in Chapter 5;
updated ICG initialization examples; expanded descriptions of LOLS and LOCS bits in ICGS1;
updated ICG electricals Table A-9 and added a figure
Minor changes to Table 7-4, Table 7-5, Table A-9;
Clarifications in Section 11.10.6, “SCI x Control Register 3 (SCIxC3)”, Section 11.7, “Interrupts
and Status Flags”, Section 11.8.1, “8- and 9-Bit Data Modes”, PTG availability in 48-pin
package (see Table 2-2)
This product incorporates SuperFlash® technology licensed from SST.
Freescale‚ and the Freescale logo are trademarks of Freescale Semiconductor, Inc.
© Freescale Semiconductor, Inc., 2004. All rights reserved.
MC9S08GB/GT Data Sheet, Rev. 2.3
4 Freescale Semiconductor
List of Chapters
Chapter 1 Introduction.............................................................................. 17
Chapter 2 Pins and Connections.............................................................23
Chapter 3 Modes of Operation.................................................................33
Chapter 4 Memory.....................................................................................39
Chapter 5 Resets, Interrupts, and System Configuration .....................61
Chapter 6 Parallel Input/Output ............................................................... 77
Chapter 7 Internal Clock Generator (ICG) Module .................................97
Chapter 8 Central Processor Unit (CPU)............................................... 125
Chapter 9 Keyboard Interrupt (KBI) Module .........................................145
Chapter 10 Timer/PWM (TPM) Module..................................................... 151
Chapter 11 Serial Communications Interface (SCI) Module..................167
Chapter 12 Serial Peripheral Interface (SPI) Module.............................. 187
Chapter 13 Inter-Integrated Circuit (IIC) Module ....................................203
Chapter 14 Analog-to-Digital Converter (ATD) Module .........................219
Chapter 15 Development Support ...........................................................235
Appendix A Electrical Characteristics......................................................259
Appendix B Ordering Information and Mechanical Drawings................281
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 5
Contents
Section Number Title Page
Chapter 1
Introduction
1.1 Overview .........................................................................................................................................17
1.2 Features ...........................................................................................................................................17
1.2.1 Standard Features of the HCS08 Family .........................................................................17
1.2.2 Features of MC9S08GB/GT Series of MCUs .................................................................17
1.2.3 Devices in the MC9S08GB/GT Series ............................................................................18
1.3 MCU Block Diagrams .....................................................................................................................19
1.4 System Clock Distribution ..............................................................................................................21
Chapter 2
Pins and Connections
2.1 Introduction .....................................................................................................................................23
2.2 Device Pin Assignment ...................................................................................................................23
2.3 Recommended System Connections ...............................................................................................26
2.3.1 Power ...............................................................................................................................28
2.3.2 Oscillator ..........................................................................................................................28
2.3.3 Reset ................................................................................................................................28
2.3.4 Background / Mode Select (PTG0/BKGD/MS) ..............................................................29
2.3.5 General-Purpose I/O and Peripheral Ports .......................................................................29
2.3.6 Signal Properties Summary .............................................................................................31
Chapter 3
Modes of Operation
3.1 Introduction .....................................................................................................................................33
3.2 Features ...........................................................................................................................................33
3.3 Run Mode ........................................................................................................................................33
3.4 Active Background Mode ................................................................................................................33
3.5 Wait Mode .......................................................................................................................................34
3.6 Stop Modes ......................................................................................................................................34
3.6.1 Stop1 Mode ......................................................................................................................35
3.6.2 Stop2 Mode ......................................................................................................................35
3.6.3 Stop3 Mode ......................................................................................................................36
3.6.4 Active BDM Enabled in Stop Mode ................................................................................36
3.6.5 LVD Enabled in Stop Mode .............................................................................................37
3.6.6 On-Chip Peripheral Modules in Stop Modes ...................................................................37
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 7
Section Number Title Page
Chapter 4
Memory
4.1 MC9S08GB/GT Memory Map .......................................................................................................39
4.1.1 Reset and Interrupt Vector Assignments ..........................................................................39
4.2 Register Addresses and Bit Assignments ........................................................................................41
4.3 RAM ................................................................................................................................................46
4.4 FLASH ............................................................................................................................................46
4.4.1 Features ............................................................................................................................47
4.4.2 Program and Erase Times ................................................................................................47
4.4.3 Program and Erase Command Execution ........................................................................48
4.4.4 Burst Program Execution .................................................................................................49
4.4.5 Access Errors ...................................................................................................................50
4.4.6 FLASH Block Protection .................................................................................................51
4.4.7 Vector Redirection ...........................................................................................................52
4.5 Security ............................................................................................................................................52
4.6 FLASH Registers and Control Bits .................................................................................................53
4.6.1 FLASH Clock Divider Register (FCDIV) .......................................................................54
4.6.2 FLASH Options Register (FOPT and NVOPT) ..............................................................55
4.6.3 FLASH Configuration Register (FCNFG) .......................................................................56
4.6.4 FLASH Protection Register (FPROT and NVPROT) ......................................................56
4.6.5 FLASH Status Register (FSTAT) .....................................................................................58
4.6.6 FLASH Command Register (FCMD) ..............................................................................59
Chapter 5
Resets, Interrupts, and System Configuration
5.1 Introduction .....................................................................................................................................61
5.2 Features ...........................................................................................................................................61
5.3 MCU Reset ......................................................................................................................................61
5.4 Computer Operating Properly (COP) Watchdog .............................................................................62
5.5 Interrupts .........................................................................................................................................62
5.5.1 Interrupt Stack Frame ......................................................................................................63
5.5.2 External Interrupt Request (IRQ) Pin ..............................................................................64
5.5.2.1 Pin Configuration Options ..............................................................................64
5.5.2.2 Edge and Level Sensitivity ..............................................................................65
5.5.3 Interrupt Vectors, Sources, and Local Masks ..................................................................65
5.6 Low-Voltage Detect (LVD) System ................................................................................................67
5.6.1 Power-On Reset Operation ..............................................................................................67
5.6.2 LVD Reset Operation .......................................................................................................67
5.6.3 LVD Interrupt Operation .................................................................................................67
5.6.4 Low-Voltage Warning (LVW) ..........................................................................................67
5.7 Real-Time Interrupt (RTI) ...............................................................................................................67
MC9S08GB/GT Data Sheet, Rev. 2.3
8 Freescale Semiconductor
Section Number Title Page
5.8 Reset, Interrupt, and System Control Registers and Control Bits ...................................................68
5.8.1 Interrupt Pin Request Status and Control Register (IRQSC) ...........................................68
5.8.2 System Reset Status Register (SRS) ................................................................................69
5.8.3 System Background Debug Force Reset Register (SBDFR) ...........................................71
5.8.4 System Options Register (SOPT) ....................................................................................71
5.8.5 System Device Identification Register (SDIDH, SDIDL) ...............................................72
5.8.6 System Real-Time Interrupt Status and Control Register (SRTISC) ...............................73
5.8.7 System Power Management Status and Control 1 Register (SPMSC1) ..........................74
5.8.8 System Power Management Status and Control 2 Register (SPMSC2) ..........................75
Chapter 6
Parallel Input/Output
6.1 Introduction .....................................................................................................................................77
6.2 Features ...........................................................................................................................................79
6.3 Pin Descriptions ..............................................................................................................................79
6.3.1 Port A and Keyboard Interrupts .......................................................................................79
6.3.2 Port B and Analog to Digital Converter Inputs ...............................................................80
6.3.3 Port C and SCI2, IIC, and High-Current Drivers ............................................................80
6.3.4 Port D, TPM1 and TPM2 .................................................................................................81
6.3.5 Port E, SCI1, and SPI ......................................................................................................81
6.3.6 Port F and High-Current Drivers .....................................................................................82
6.3.7 Port G, BKGD/MS, and Oscillator ..................................................................................82
6.4 Parallel I/O Controls ........................................................................................................................82
6.4.1 Data Direction Control ....................................................................................................83
6.4.2 Internal Pullup Control ....................................................................................................83
6.4.3 Slew Rate Control ............................................................................................................83
6.5 Stop Modes ......................................................................................................................................84
6.6 Parallel I/O Registers and Control Bits ...........................................................................................84
6.6.1 Port A Registers (PTAD, PTAPE, PTASE, and PTADD) ................................................84
6.6.2 Port B Registers (PTBD, PTBPE, PTBSE, and PTBDD) ...............................................86
6.6.3 Port C Registers (PTCD, PTCPE, PTCSE, and PTCDD) ...............................................87
6.6.4 Port D Registers (PTDD, PTDPE, PTDSE, and PTDDD) ..............................................89
6.6.5 Port E Registers (PTED, PTEPE, PTESE, and PTEDD) ................................................90
6.6.6 Port F Registers (PTFD, PTFPE, PTFSE, and PTFDD) ..................................................92
6.6.7 Port G Registers (PTGD, PTGPE, PTGSE, and PTGDD) ..............................................93
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 9
Section Number Title Page
Chapter 7
Internal Clock Generator (ICG) Module
7.1 Introduction .....................................................................................................................................99
7.1.1 Features ..........................................................................................................................100
7.1.2 Modes of Operation .......................................................................................................101
7.2 External Signal Description ..........................................................................................................101
7.2.1 Overview ........................................................................................................................101
7.2.2 Detailed Signal Descriptions .........................................................................................102
7.2.2.1 EXTAL— External Reference Clock / Oscillator Input ...............................102
7.2.2.2 XTAL— Oscillator Output ...........................................................................102
7.2.3 External Clock Connections ..........................................................................................102
7.2.4 External Crystal/Resonator Connections .......................................................................102
7.3 Functional Description ..................................................................................................................103
7.3.1 Off Mode (Off) ..............................................................................................................103
7.3.1.1 BDM Active .................................................................................................103
7.3.1.2 OSCSTEN Bit Set .........................................................................................103
7.3.1.3 Stop/Off Mode Recovery ..............................................................................104
7.3.2 Self-Clocked Mode (SCM) ............................................................................................104
7.3.3 FLL Engaged, Internal Clock (FEI) Mode ....................................................................105
7.3.3.1 FLL Engaged Internal Unlocked ..................................................................105
7.3.3.2 FLL Engaged Internal Locked ......................................................................106
7.3.4 FLL Bypassed, External Clock (FBE) Mode ................................................................106
7.3.5 FLL Engaged, External Clock (FEE) Mode ..................................................................106
7.3.5.1 FLL Engaged External Unlocked .................................................................106
7.3.5.2 FLL Engaged External Locked .....................................................................107
7.3.6 FLL Lock and Loss-of-Lock Detection .........................................................................107
7.3.7 FLL Loss-of-Clock Detection ........................................................................................107
7.3.8 Clock Mode Requirements ............................................................................................108
7.3.9 Fixed Frequency Clock ..................................................................................................109
7.4 Initialization/Application Information ..........................................................................................110
7.4.1 Introduction ....................................................................................................................110
7.4.2 Example #1: External Crystal = 32 kHz, Bus Frequency = 4.19 MHz .........................112
7.4.3 Example #2: External Crystal = 4 MHz, Bus Frequency = 20 MHz ............................113
7.4.4 Example #3: No External Crystal Connection, 5.4 MHz Bus Frequency .....................114
7.4.5 Example #4: Internal Clock Generator Trim .................................................................116
7.5 ICG Registers and Control Bits .....................................................................................................117
7.5.1 ICG Control Register 1 (ICGC1) ......................................................................118
7.5.2 ICG Control Register 2 (ICGC2) ......................................................................119
7.5.3 ICG Status Register 1 (ICGS1) .................................................................................120
7.5.4 ICG Status Register 2 (ICGS2) ........................................................................122
7.5.5 ICG Filter Registers (ICGFLTU, ICGFLTL) ....................................................... 122
7.5.6 ICG Trim Register (ICGTRM) ...........................................................................123
MC9S08GB/GT Data Sheet, Rev. 2.3
10 Freescale Semiconductor
Section Number Title Page
Chapter 8
Central Processor Unit (CPU)
8.1 Introduction ...................................................................................................................................125
8.2 Features .........................................................................................................................................126
8.3 Programmer’s Model and CPU Registers .....................................................................................126
8.3.1 Accumulator (A) ............................................................................................................127
8.3.2 Index Register (H:X) .....................................................................................................127
8.3.3 Stack Pointer (SP) ..........................................................................................................128
8.3.4 Program Counter (PC) ...................................................................................................128
8.3.5 Condition Code Register (CCR) ....................................................................................128
8.4 Addressing Modes .........................................................................................................................130
8.4.1 Inherent Addressing Mode (INH) ..................................................................................130
8.4.2 Relative Addressing Mode (REL) .................................................................................130
8.4.3 Immediate Addressing Mode (IMM) .............................................................................130
8.4.4 Direct Addressing Mode (DIR) .....................................................................................130
8.4.5 Extended Addressing Mode (EXT) ...............................................................................131
8.4.6 Indexed Addressing Mode .............................................................................................131
8.4.6.1 Indexed, No Offset (IX) ................................................................................131
8.4.6.2 Indexed, No Offset with Post Increment (IX+) .............................................131
8.4.6.3 Indexed, 8-Bit Offset (IX1) ...........................................................................131
8.4.6.4 Indexed, 8-Bit Offset with Post Increment (IX1+) .......................................131
8.4.6.5 Indexed, 16-Bit Offset (IX2) .........................................................................131
8.4.6.6 SP-Relative, 8-Bit Offset (SP1) ....................................................................131
8.4.6.7 SP-Relative, 16-Bit Offset (SP2) ..................................................................132
8.5 Special Operations .........................................................................................................................132
8.5.1 Reset Sequence ..............................................................................................................132
8.5.2 Interrupt Sequence .........................................................................................................132
8.5.3 Wait Mode Operation .....................................................................................................133
8.5.4 Stop Mode Operation .....................................................................................................133
8.5.5 BGND Instruction ..........................................................................................................134
8.6 HCS08 Instruction Set Summary ..................................................................................................134
Chapter 9
Keyboard Interrupt (KBI) Module
9.1 Introduction ...................................................................................................................................145
9.1.1 Port A and Keyboard Interrupt Pins ..............................................................................145
9.2 Features .........................................................................................................................................145
9.3 KBI Block Diagram ......................................................................................................................147
9.4 Keyboard Interrupt (KBI) Module ................................................................................................147
9.4.1 Pin Enables ....................................................................................................................147
9.4.2 Edge and Level Sensitivity ............................................................................................147
9.4.3 KBI Interrupt Controls ...................................................................................................148
9.5 KBI Registers and Control Bits .....................................................................................................148
9.5.1 KBI Status and Control Register (KBI1SC) ..................................................................148
9.5.2 KBI Pin Enable Register (KBI1PE) ..............................................................................150
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 11
Section Number Title Page
Chapter 10
Timer/PWM (TPM) Module
10.1 Introduction ...................................................................................................................................151
10.2 Features .........................................................................................................................................151
10.3 TPM Block Diagram .....................................................................................................................153
10.4 Pin Descriptions ............................................................................................................................154
10.4.1 External TPM Clock Sources ........................................................................................154
10.4.2 TPMxCHn — TPMx Channel n I/O Pins ......................................................................154
10.5 Functional Description ..................................................................................................................154
10.5.1 Counter ..........................................................................................................................155
10.5.2 Channel Mode Selection ................................................................................................156
10.5.2.1 Input Capture Mode ......................................................................................156
10.5.2.2 Output Compare Mode .................................................................................156
10.5.2.3 Edge-Aligned PWM Mode ...........................................................................156
10.5.3 Center-Aligned PWM Mode ..........................................................................................157
10.6 TPM Interrupts ..............................................................................................................................159
10.6.1 Clearing Timer Interrupt Flags ......................................................................................159
10.6.2 Timer Overflow Interrupt Description ...........................................................................159
10.6.3 Channel Event Interrupt Description .............................................................................159
10.6.4 PWM End-of-Duty-Cycle Events ..................................................................................160
10.7 TPM Registers and Control Bits ...................................................................................................160
10.7.1 Timer x Status and Control Register (TPMxSC) ...........................................................160
10.7.2 Timer x Counter Registers (TPMxCNTH:TPMxCNTL) ..............................................162
10.7.3 Timer x Counter Modulo Registers (TPMxMODH:TPMxMODL) ..............................163
10.7.4 Timer x Channel n Status and Control Register (TPMxCnSC) .....................................163
10.7.5 Timer x Channel Value Registers (TPMxCnVH:TPMxCnVL) .....................................165
Chapter 11
Serial Communications Interface (SCI) Module
11.1 Introduction ...................................................................................................................................167
11.2 Features .........................................................................................................................................169
11.3 SCI System Description ................................................................................................................169
11.4 Baud Rate Generation ...................................................................................................................169
11.5 Transmitter Functional Description ...............................................................................................170
11.5.1 Transmitter Block Diagram ...........................................................................................170
11.5.2 Send Break and Queued Idle .........................................................................................172
11.6 Receiver Functional Description ...................................................................................................172
11.6.1 Receiver Block Diagram ................................................................................................172
11.6.2 Data Sampling Technique ..............................................................................................174
11.6.3 Receiver Wakeup Operation ..........................................................................................174
11.6.3.1 Idle-Line Wakeup ..........................................................................................175
11.6.3.2 Address-Mark Wakeup .................................................................................175
11.7 Interrupts and Status Flags ............................................................................................................175
MC9S08GB/GT Data Sheet, Rev. 2.3
12 Freescale Semiconductor
Section Number Title Page
11.8 Additional SCI Functions ..............................................................................................................176
11.8.1 8- and 9-Bit Data Modes ................................................................................................176
11.9 Stop Mode Operation ....................................................................................................................176
11.9.1 Loop Mode .....................................................................................................................177
11.9.2 Single-Wire Operation ...................................................................................................177
11.10 SCI Registers and Control Bits .....................................................................................................177
11.10.1 SCI x Baud Rate Registers (SCIxBDH, SCIxBDL) ......................................................177
11.10.2 SCI x Control Register 1 (SCIxC1) ...............................................................................178
11.10.3 SCI x Control Register 2 (SCIxC2) ...............................................................................180
11.10.4 SCI x Status Register 1 (SCIxS1) ..................................................................................181
11.10.5 SCI x Status Register 2 (SCIxS2) ..................................................................................183
11.10.6 SCI x Control Register 3 (SCIxC3) ...............................................................................184
11.10.7 SCI x Data Register (SCIxD) ........................................................................................185
Chapter 12
Serial Peripheral Interface (SPI) Module
12.1 Features .........................................................................................................................................189
12.2 Block Diagrams .............................................................................................................................189
12.2.1 SPI System Block Diagram ...........................................................................................189
12.2.2 SPI Module Block Diagram ...........................................................................................190
12.2.3 SPI Baud Rate Generation .............................................................................................192
12.3 Functional Description ..................................................................................................................192
12.3.1 SPI Clock Formats .........................................................................................................193
12.3.2 SPI Pin Controls ............................................................................................................195
12.3.2.1 SPSCK1 — SPI Serial Clock ........................................................................195
12.3.2.2 MOSI1 — Master Data Out, Slave Data In ..................................................195
12.3.2.3 MISO1 — Master Data In, Slave Data Out ..................................................195
12.3.2.4
12.3.3 SPI Interrupts .................................................................................................................196
12.3.4 Mode Fault Detection ....................................................................................................196
12.4 SPI Registers and Control Bits ......................................................................................................196
12.4.1 SPI Control Register 1 (SPI1C1) ...................................................................................197
12.4.2 SPI Control Register 2 (SPI1C2) ...................................................................................198
12.4.3 SPI Baud Rate Register (SPI1BR) .................................................................................199
12.4.4 SPI Status Register (SPI1S) ...........................................................................................201
12.4.5 SPI Data Register (SPI1D) ............................................................................................202
SS1 — Slave Select .......................................................................................195
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 13
Section Number Title Page
Chapter 13
Inter-Integrated Circuit (IIC) Module
13.1 Introduction ...................................................................................................................................205
13.1.1 Features ..........................................................................................................................205
13.1.2 Modes of Operation .......................................................................................................205
13.1.3 Block Diagram ...............................................................................................................206
13.1.4 Detailed Signal Descriptions .........................................................................................206
13.1.4.1 SCL1 — Serial Clock Line ...........................................................................206
13.1.4.2 SDA1 — Serial Data Line ............................................................................206
13.2 Functional Description ..................................................................................................................207
13.2.1 IIC Protocol ...................................................................................................................207
13.2.1.1 START Signal ...............................................................................................208
13.2.1.2 Slave Address Transmission .........................................................................208
13.2.1.3 Data Transfer .................................................................................................208
13.2.1.4 STOP Signal ..................................................................................................209
13.2.1.5 Repeated START Signal ...............................................................................209
13.2.1.6 Arbitration Procedure ....................................................................................209
13.2.1.7 Clock Synchronization ..................................................................................209
13.2.1.8 Handshaking .................................................................................................210
13.2.1.9 Clock Stretching ............................................................................................210
13.3 Resets ............................................................................................................................................210
13.4 Interrupts .......................................................................................................................................211
13.4.1 Byte Transfer Interrupt ..................................................................................................211
13.4.2 Address Detect Interrupt ................................................................................................211
13.4.3 Arbitration Lost Interrupt ..............................................................................................211
13.5 IIC Registers and Control Bits ......................................................................................................212
13.5.1 IIC Address Register (IIC1A) ........................................................................................212
13.5.2 IIC Frequency Divider Register (IIC1F) ........................................................................212
13.5.3 IIC Control Register (IIC1C) .........................................................................................215
13.5.4 IIC Status Register (IIC1S) ............................................................................................216
13.5.5 IIC Data I/O Register (IIC1D) .......................................................................................217
Chapter 14
Analog-to-Digital Converter (ATD) Module
14.1 Introduction ...................................................................................................................................221
14.1.1 Features ..........................................................................................................................221
14.1.2 Modes of Operation .......................................................................................................221
14.1.2.1 Stop Mode .....................................................................................................221
14.1.2.2 Power Down Mode .......................................................................................221
14.1.3 Block Diagram ...............................................................................................................221
14.2 Signal Description .........................................................................................................................222
14.2.1 Overview ........................................................................................................................222
14.2.1.1 Channel Input Pins — AD1P7–AD1P0 ........................................................223
MC9S08GB/GT Data Sheet, Rev. 2.3
14 Freescale Semiconductor
Section Number Title Page
14.2.1.2 ATD Reference Pins — V
14.2.1.3 ATD Supply Pins — V
DDAD
REFH
, V
, V
SSAD
........................................................223
REFL
...........................................................223
14.3 Functional Description ..................................................................................................................223
14.3.1 Mode Control .................................................................................................................223
14.3.2 Sample and Hold ............................................................................................................224
14.3.3 Analog Input Multiplexer ..............................................................................................226
14.3.4 ATD Module Accuracy Definitions ...............................................................................226
14.4 Resets ............................................................................................................................................229
14.5 Interrupts .......................................................................................................................................229
14.6 ATD Registers and Control Bits ....................................................................................................229
14.6.1 ATD Control (ATDC) ....................................................................................................230
14.6.2 ATD Status and Control (ATD1SC) ..............................................................................232
14.6.3 ATD Result Data (ATD1RH, ATD1RL) ........................................................................234
14.6.4 ATD Pin Enable (ATD1PE) ...........................................................................................234
Chapter 15
Development Support
15.1 Introduction ...................................................................................................................................235
15.2 Features .........................................................................................................................................236
15.3 Background Debug Controller (BDC) ..........................................................................................237
15.3.1 BKGD Pin Description ..................................................................................................237
15.3.2 Communication Details .................................................................................................238
15.3.3 BDC Commands ............................................................................................................242
15.3.4 BDC Hardware Breakpoint ............................................................................................244
15.4 On-Chip Debug System (DBG) ....................................................................................................245
15.4.1 Comparators A and B ....................................................................................................245
15.4.2 Bus Capture Information and FIFO Operation ..............................................................245
15.4.3 Change-of-Flow Information .........................................................................................246
15.4.4 Tag vs. Force Breakpoints and Triggers ........................................................................246
15.4.5 Trigger Modes ................................................................................................................247
15.4.6 Hardware Breakpoints ...................................................................................................249
15.5 Registers and Control Bits .............................................................................................................249
15.5.1 BDC Registers and Control Bits ....................................................................................249
15.5.1.1 BDC Status and Control Register (BDCSCR) ..............................................250
15.5.1.2 BDC Breakpoint Match Register (BDCBKPT) ............................................251
15.5.2 System Background Debug Force Reset Register (SBDFR) .........................................251
15.5.3 DBG Registers and Control Bits ....................................................................................252
15.5.3.1 Debug Comparator A High Register (DBGCAH) ........................................252
15.5.3.2 Debug Comparator A Low Register (DBGCAL) .........................................252
15.5.3.3 Debug Comparator B High Register (DBGCBH) .........................................252
15.5.3.4 Debug Comparator B Low Register (DBGCBL) ..........................................252
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 15
Section Number Title Page
15.5.3.5 Debug FIFO High Register (DBGFH) ..........................................................253
15.5.3.6 Debug FIFO Low Register (DBGFL) ...........................................................253
15.5.3.7 Debug Control Register (DBGC) ..................................................................254
15.5.3.8 Debug Trigger Register (DBGT) ..................................................................255
15.5.3.9 Debug Status Register (DBGS) .....................................................................256
Appendix A
Electrical Characteristics
A.1 Introduction ...................................................................................................................................259
A.2 Absolute Maximum Ratings ..........................................................................................................259
A.3 Thermal Characteristics .................................................................................................................260
A.4 Electrostatic Discharge (ESD) Protection Characteristics ............................................................261
A.5 DC Characteristics .........................................................................................................................261
A.6 Supply Current Characteristics ......................................................................................................265
A.7 ATD Characteristics ......................................................................................................................269
A.8 Internal Clock Generation Module Characteristics .......................................................................271
A.8.1 ICG Frequency Specifications ........................................................................................271
A.9 AC Characteristics .........................................................................................................................273
A.9.1 Control Timing ...............................................................................................................273
A.9.2 Timer/PWM (TPM) Module Timing ..............................................................................274
A.9.3 SPI Timing ......................................................................................................................275
A.10 FLASH Specifications ...................................................................................................................279
Appendix B
Ordering Information and Mechanical Drawings
B.1 Ordering Information ....................................................................................................................281
B.2 Mechanical Drawings ....................................................................................................................281
B.3 64-Pin LQFP Package Drawing ....................................................................................................282
B.4 48-Pin QFN Package Drawing ......................................................................................................283
B.5 44-Pin QFP Package Drawing .......................................................................................................284
B.6 42-Pin SDIP Package Drawing .....................................................................................................285
MC9S08GB/GT Data Sheet, Rev. 2.3
16 Freescale Semiconductor
Chapter 1 Introduction
1.1 Overview
The MC9S08GB/GT are members of the low-cost, high-performance HCS08 Family of 8-bit
microcontroller units (MCUs). All MCUs in the family use the enhanced HCS08 core and are available
with a variety of modules, memory sizes, memory types, and package types.
1.2 Features
Features have been organized to reflect:
• Standard features of the HCS08 Family
• Features of the MC9S08GB/GT MCU
1.2.1 Standard Features of the HCS08 Family
• 40-MHz HCS08 CPU (central processor unit)
• HC08 instruction set with added BGND instruction
• Background debugging system (see also Chapter 15, “Development Support”)
• Breakpoint capability to allow single breakpoint setting during in-circuit debugging (plus two more
breakpoints in on-chip debug module)
• Debug module containing two comparators and nine trigger modes. Eight deep FIFO for storing
change-of-flow addresses and event-only data. Debug module supports both tag and force
breakpoints.
• Support for up to 32 interrupt/reset sources
• Power-saving modes: wait plus three stops
• System protection features:
— Optional computer operating properly (COP) reset
— Low-voltage detection with reset or interrupt
— Illegal opcode detection with reset
— Illegal address detection with reset (some devices don’t have illegal addresses)
1.2.2 Features of MC9S08GB/GT Series of MCUs
• On-chip in-circuit programmable FLASH memory with block protection and security options (see
Table 1-1 for device specific information)
• On-chip random-access memory (RAM) (see Table 1-1 for device specific information)
• 8-channel, 10-bit analog-to-digital converter (ATD)
• Two serial communications interface modules (SCI)
• Serial peripheral interface module (SPI)
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 17
Chapter 1 Introduction
• Multiple clock source options:
— Internally generated clock with ±0.2% trimming resolution and ±0.5% deviation across
voltage.
— Crystal
— Resonator, or
— External clock
• Inter-integrated circuit bus module to operate up to 100 kbps (IIC)
• One 3-channel and one 5-channel 16-bit timer/pulse width modulator (TPM) modules with
selectable input capture, output compare, and edge-aligned PWM capability on each channel. Each
timer module may be configured for buffered, centered PWM (CPWM) on all channels (TPMx).
• 8-pin keyboard interrupt module (KBI)
• 16 high-current pins (limited by package dissipation)
• Software selectable pullups on ports when used as input. Selection is on an individual port bit basis.
During output mode, pullups are disengaged.
• Internal pullup on
RESET and IRQ pin to reduce customer system cost
• Up to 56 general-purpose input/output (I/O) pins, depending on package selection
• 64-pin low-profile quad flat package (LQFP) — MC9S08GBxx
• 48-pin quad flat package, no lead (QFN) — MC9S08GTxx
• 44-pin quad flat package (QFP) — MC9S08GTxx
• 42-pin shrink dual in-line package (SDIP) — MC9S08GTxx
1.2.3 Devices in the MC9S08GB/GT Series
Table 1-1 lists the devices available in the MC9S08GB/GT series and summarizes the differences among
them.
Table 1-1. Devices in the MC9S08GB/GT Series
Device FLASH RAM TPM I/O Packages
MC9S08GB60 60K 4K One 3-channel and one
5-channel, 16-bit timer
MC9S08GB32 32K 2K One 3-channel and one
5-channel, 16-bit timer
MC9S08GT60 60K 4K Two 2-channel,
16-bit timers
MC9S08GT32 32K 2K Two 2-channel,
16-bit timers
MC9S08GT16 16K 1K Two 2-channel,
16-bit timers
1
The 48-pin QFN package has one 3-channel and one 2-channel 16-bit TPM.
56 64 LQFP
56 64 LQFP
39
36
34
39
36
34
39
36
34
48 QFN
44 QFP
42 SDIP
48 QFN
44 QFP
42 SDIP
48 QFN
44 QFP
42 SDIP
1
(1)
(1)
MC9S08GB/GT Data Sheet, Rev. 2.3
18 Freescale Semiconductor
1.3 MCU Block Diagrams
These block diagrams show the structure of the MC9S08GB/GT MCUs.
MCU Block Diagrams
RESET
NOTE 4
IRQ
NOTES 2, 3
V
DDAD
V
SSAD
V
REFH
V
REFL
HCS08 CORE
BDC
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION
POWER MANAGEMENT
RTI
IRQ LVD
USER FLASH
(GB60 = 61,268 BYTES)
(GB32 = 32,768 BYTES)
USER RAM
(GB60 = 4096 BYTES)
(GB32 = 2048 BYTES)
ANALOG-TO-DIGITAL
CONVERTER (ATD1)
INTERNAL CLOCK
GENERATOR (ICG)
LOW-POWER OSCILLATOR
CPU
COP
10-BIT
INTERNAL BUS
DEBUG
MODULE (DBG)
8-BIT KEYBOARD
INTERRUPT MODULE (KBI1)
IIC MODULE (IIC1)
SERIAL COMMUNICATIONS
INTERFACE MODULE (SCI1)
SERIAL COMMUNICATIONS
INTERFACE MODULE (SCI2)
3-CHANNEL TIMER/PWM
MODULE (TPM1)
5-CHANNEL TIMER/PWM
MODULE (TPM2)
SERIAL PERIPHERAL
INTERFACE MODULE (SPI1)
PORT A
PORT B
PORT C
PORT D
PORT E
PORT F
8
PTA7/KBI1P7–
PTA0/KBI1P0
8
PTB7/AD1P7–
PTB0/AD1P0
PTC7
PTC6
PTC5
PTC4
PTC3/SCL1
PTC2/SDA1
PTC1/RxD2
PTC0/TxD2
PTD7/TPM2CH4
PTD6/TPM2CH3
PTD5/TPM2CH2
PTD4/TPM2CH1
PTD3/TPM2CH0
PTD2/TPM1CH2
PTD1/TPM1CH1
PTD0/TPM1CH0
PTE7
PTE6
PTE5/SPSCK1
PTE4/MOSI1
PTE3/MISO1
PTE2/SS1
PTE1/RxD1
PTE0/TxD1
8
PTF7–PTF0
NOTES 1, 6
NOTE 1
NOTES 1, 5
NOTE 1
NOTE 1
NOTES 1, 5
V
DD
V
SS
VOLTAGE
REGULATOR
NOTES:
1. Port pins are software configurable with pullup device if input port.
2. Pin contains software configurable pullup/pulldown device if IRQ
enabled (IRQPE = 1).
3. IRQ does not have a clamp diode to V
above V
4. Pin contains integrated pullup device.
DD
.
. IRQ should not be driven
DD
PORT G
PTG7
PTG6
PTG5
PTG4
PTG3
PTG2/EXTAL
PTG1/XTAL
PTG0/BKGD/MS
NOTE 1
5. High current drive
6. Pins PTA[7:4] contain both pullup and pulldown devices. Pulldown
available when KBI enabled (KBIPn = 1).
Figure 1-1. MC9S08GBxx Block Diagram
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 19
Chapter 1 Introduction
RESET
NOTE 4
IRQ
NOTES 2, 3
V
DDAD
V
SSAD
V
REFH
V
REFL
V
DD
V
SS
HCS08 CORE
BDC
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION
POWER MANAGEMENT
RTI
IRQ LVD
USER FLASH
(GT60 = 61,268 BYTES)
(GT32 = 32,768 BYTES)
(GT16 = 16,384 BYTES)
USER RAM
(GT60 = 4096 BYTES)
(GT32 = 2048 BYTES)
(GT16 = 1024 BYTES)
ANALOG-TO-DIGITAL
CONVERTER (ATD1)
INTERNAL CLOCK
GENERATOR (ICG)
LOW-POWER OSCILLATOR
VOLTAGE
REGULATOR
CPU
COP
10-BIT
INTERNAL BUS
DEBUG
MODULE (DBG)
8-BIT KEYBOARD
INTERRUPT MODULE (KBI1)
IIC MODULE (IIC1)
SERIAL COMMUNICATIONS
INTERFACE MODULE (SCI1)
SERIAL COMMUNICATIONS
INTERFACE MODULE (SCI2)
3-CHANNEL TIMER/PWM
MODULE (TPM1)
(NOTE 8)
5-CHANNEL TIMER/PWM
MODULE (TPM2)
(NOTE 8)
SERIAL PERIPHERAL
INTERFACE MODULE (SPI1)
PORT A
PORT B
PORT C
PORT D
PORT E
PORT G
8
PTA7/KBI1P7–
PTA0/KBI1P0
8
PTB7/AD1P7–
PTB0/AD1P0
PTC6 (NOTE 6)
PTC5 (NOTE 6)
PTC4
PTC3/SCL1
PTC2/SDA1
PTC1/RxD2
PTC0/TxD2
PTD4/TPM2CH1
PTD3/TPM2CH0
PTD1/TPM1CH1
PTD0/TPM1CH0
PTE5/SPSCK1
PTE4/MOSI1
PTE3/MISO1
PTE2/SS1
PTE1/RxD1
PTE0/TxD1
PTG2/EXTAL
PTG1/XTAL
PTG0/BKGD/MS
NOTES 1, 7
NOTE 1
NOTES 1, 5
NOTE 1
NOTE 1
NOTE 1
NOTES:
1. Port pins are software configurable with pullup device if input port.
2. Pin contains software configurable pullup/pulldown device if IRQ enabled (IRQPE = 1).
3. IRQ does not have a clamp diode to V
4. Pin contains integrated pullup device.
. IRQ should not be driven above VDD.
DD
5. High current drive
6. PTC[6:5] are not available on the 42-pin SDIP package.
7. Pins PTA[7:4] contain both pullup and pulldown devices. Pulldown available when KBI enabled (KBIPn = 1).
8. Only two timer channels per TPM are bonded out. All channels are available for use as software compare.
Figure 1-2. MC9S08GTxx Block Diagram
MC9S08GB/GT Data Sheet, Rev. 2.3
20 Freescale Semiconductor
Table 1-2 lists the functional versions of the on-chip modules.
Table 1-2. Block Versions
Module Version
Analog-to-Digital Converter (ATD) 3
Internal Clock Generator (ICG) 2
Inter-Integrated Circuit (IIC) 1
Keyboard Interrupt (KBI) 1
Serial Communications Interface (SCI) 1
Serial Peripheral Interface (SPI) 3
Timer Pulse-Width Modulator (TPM) 1
Central Processing Unit (CPU) 2
1.4 System Clock Distribution
System Clock Distribution
ICGERCLK
FFE
SYSTEM
CONTROL
LOGIC
RTI
TPM1 TPM2 IIC1 SCI1 SCI2 SPI1
÷2
ICG
ICGOUT
ICGLCLK*
CPU
* ICGLCLK is the alternate BDC clock source for the MC9S08GB/GT.
FIXED FREQ CLOCK (XCLK)
÷2
BUSCLK
BDC
ATD1
ATD has min and max
frequency requirements.
See Chapter 1, “Introduction”
and Appendix A, “Electrical
Characteristics.
RAM FLASH
FLASH has frequency
requirements for program
and erase operation.
See Appendix A, “Electrical
Characteristics.
Figure 1-3. System Clock Distribution Diagram
Some of the modules inside the MCU have clock source choices. Figure 1-3 shows a simplified clock
connection diagram. The ICG supplies the clock sources:
• ICGOUT is an output of the ICG module. It is one of the following:
— The external crystal oscillator
— An external clock source
— The output of the digitally-controlled oscillator (DCO) in the frequency-locked loop
sub-module
Control bits inside the ICG determine which source is connected.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 21
Chapter 1 Introduction
• FFE is a control signal generated inside the ICG. If the frequency of ICGOUT > 4 × the frequency
of ICGERCLK, this signal is a logic 1 and the fixed-frequency clock will be the ICGERCLK.
Otherwise the fixed-frequency clock will be BUSCLK.
• ICGLCLK — Development tools can select this internal self-clocked source (~ 8 MHz) to speed
up BDC communications in systems where the bus clock is slow.
• ICGERCLK — External reference clock can be selected as the real-time interrupt clock source.
MC9S08GB/GT Data Sheet, Rev. 2.3
22 Freescale Semiconductor
Chapter 2 Pins and Connections
2.1 Introduction
This section describes signals that connect to package pins. It includes a pinout diagram, a table of signal
properties, and detailed discussion of signals.
2.2 Device Pin Assignment
DDAD
SSAD
57
V
V
56
PTF1
PTF0
PTA7/KBI1P7
PTA5/KBI1P5
PTA6/KBI1P6
PTA4/KBI1P4
505152535455
PTA3/KBI1P3
49
48
47
46
45
44
43
42
41
40
PTA2/KBI1P2
PTA1/KBI1P1
PTA0/KBI1P0
PTF7
PTF6
PTF5
V
REFL
V
REFH
PTB7/AD1P7
RESET
PTG7
PTC0/TxD2
PTC1/RxD2
PTC2/SDA1
PTC3/SCL1
PTC4
PTC5
PTC6
PTG6
PTG5
PTG4
64
63 62 61
1
2
3
4
5
6
7
8
9
PTG2/EXTAL
PTG3
60
PTG0/BKGD/MS
PTG1/XTAL
58
59
PTC7
PTF2
PTF3
PTF4
PTE0/TxD1
PTE1/RxD1
IRQ
16
10
11
12
13
14
15
17
PTE2/SS1
19
18
PTE4/MOSI1
PTE3/MISO1
20 21 22
PTE6
PTE5/SPSCK1
23
PTE7
27
24
25
26
SS
DD
V
V
PTD0/TPM1CH0
28 29 30 31
PTD1/TPM1CH1
PTD2/TPM1CH2
PTD3/TPM2CH0
PTD5/TPM2CH2
PTD4/TPM2CH1
39
PTB6/AD1P6
38
PTB5/AD1P5
37
PTB4/AD1P4
PTB3/AD1P3
36
35
PTB2/AD1P2
34
PTB1/AD1P1
PTB0/AD1P0
33
32
PTD6/TPM2CH3
PTD7/TPM2CH4
Figure 2-1. MC9S08GBxx in 64-Pin LQFP Package
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 23
Chapter 2 Pins and Connections
RESET
PTC0/TxD2
PTC1/RxD2
PTC2/SDA1
PTC3/SCL1
PTC4
PTC5
PTC6
PTE0/TxD1
PTE1/RxD1
PTC7
IRQ
DDAD
SSAD
PTG2/EXTAL
PTG1/XTAL
PTG3
47
48
1
PTG0/BKGD/MS
46
45
V
V
44
43
PTA6/KBI1P6
PTA7/KBI1P7
42
41
2
3
4
5
6
7
8
9
10
11
12
14
15
16
17
18
19
13
20
PTA4/KBI1P4
PTA5/KBI1P5
40
21
PTA3/KBI1P3
39
38
22
23
PTA2/KBI1P2
37
PTA1/KBI1P1
36
PTA0/KBI1P0
35
V
34
REFL
V
33
REFH
PTB7/AD1P7
32
PTB6/AD1P6
31
PTB5/AD1P5
30
PTB4/AD1P4
29
PTB3/AD1P3
28
PTB2/AD1P2
27
PTB1/AD1P1
26
PTB0/AD1P0
25
24
SS2
V
DD
V
SS1
V
PTE2/SS1
PTE3/MISO1
PTE5/SPSCK1
PTE4/MOSI1
PTD1/TPM1CH1
PTD0/TPM1CH0
PTD2/TPM1CH2
PTD3/TPM2CH0
PTD4/TPM2CH1
Figure 2-2. MC9S08GTxx in 48-Pin QFN Package
MC9S08GB/GT Data Sheet, Rev. 2.3
24 Freescale Semiconductor
RESET
PTC0/TxD2
PTC1/RxD2
PTC2/SDA1
PTC3/SCL1
PTC4
PTC5
PTC6
PTE0/TxD1
PTE1/RxD1
IRQ
1
11
PTG2/EXTAL
44
2
3
4
5
6
7
8
9
10
12
PTG1/XTAL
PTG0/BKGD/MS
43
42
13
14
SSAD
V
41
15
DDAD
V
PTA7/KBI1P7
40
16
17
SS
DD
V
V
PTA6/KBI1P6
39
38
18
PTA4/KBI1P4
PTA5/KBI1P5
37
19
PTA3/KBI1P3
36
35
20
21
PTA2/KBI1P2
34
PTA1/KBI1P1
33
PTA0/KBI1P0
32
V
31
30
29
28
27
26
25
24
REFL
V
REFH
PTB7/AD1P7
PTB6/AD1P6
PTB5/AD1P5
PTB4/AD1P4
PTB3/AD1P3
PTB2/AD1P2
PTB1/AD1P1
23
22
Device Pin Assignment
PTE2/SS1
PTE3/MISO1
PTE4/MOSI1
PTE5/SPSCK1
PTD1/TPM1CH1
PTD0/TPM1CH0
PTD3/TPM2CH0
PTB0/AD1P0
PTD4/TPM2CH1
Figure 2-3. MC9S08GTxx in 44-Pin QFP Package
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 25
Chapter 2 Pins and Connections
V
DDAD
V
SSAD
PTG0/BKGD/MS
PTG1/XTAL
PTG2/EXTAL
RESET
PTC0/TxD2
PTC1/RXD2
PTC2/SDA1
PTC3/SCL1
PTC4
PTE0/TxD1
PTE1/RxD1
IRQ
PTE2/
SS1
PTE3/MISO1
PTE4/MOSI1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15 28
16 27
17 26
42
41
40
39
38
37
36
35
34
33
32
31
30
29
PTA7/KBI1P7
PTA6/KBI1P6
PTA5/KBI1P5
PTA4/KBI1P4
PTA3/KBI1P3
PTA2/KBI1P2
PTA1/KBI1P1
PTA0/KBI1P0
V
REFL
V
REFH
PTB7/AD1P7
PTB6/AD1P6
PTB5/AD1P5
PTB4/AD1P4
PTB3/AD1P3
PTB2/AD1P2
PTB1/AD1P1
PTE5/SPSCK1
V
SS
V
DD
PTD0/TPM1CH0
18 25
19 24
20 23
21 22
PTB0/AD1P0
PTD4/TPM2CH1
PTD3/TPM2CH0
PTD1/TPM1CH1
Figure 2-4. MC9S08GTxx in 42-Pin SDIP Package
2.3 Recommended System Connections
Figure 2-5 shows pin connections that are common to almost all MC9S08GB60 application systems.
MC9S08GTxx connections will be similar except for the number of I/O pins available. A more detailed
discussion of system connections follows.
MC9S08GB/GT Data Sheet, Rev. 2.3
26 Freescale Semiconductor
SYSTEM
POWER
NOTE 1
C1
BACKGROUND HEADER
V
DD
NOTES:
1. Not required if
using the internal
oscillator option.
2. These are the
same pins as
PTG1 and PTG2.
3. BKGD/MS is the
same pin as PTG0.
4. The 48-pin QFN
has 2 V
(V
SS1
both of which must
be connected to
GND.
+
3 V
10 µF
OPTIONAL
MANUAL
RESET
pins
SS
and V
V
DD
+
C
BLK
R
F
X1
ASYNCHRONOUS
PTG0/BKDG/MS
),
SS2
C
BY
0.1 µF
C2
INTERRUPT
INPUT
PTG1/XTAL
PTG2/EXTAL
PTG3
PTG4
PTG5
PTG6
PTG7
PTF0
PTF1
PTF2
PTF3
PTF4
PTF5
PTF6
PTF7
C
BYAD
0.1 µF
R
S
V
REFH
V
DDAD
V
SSAD
V
REFL
V
DD
V
SS
NOTE 4
XTAL
NOTE 2
EXTAL
NOTE 2
PORT
G
PORT
F
MC9S08GBxx
BKGD/MS
NOTE 3
RESET
IRQ
PORT
A
PORT
B
PORT
C
PORT
D
PORT
E
Recommended System Connections
PTA0/KBI1P0
PTA1/KBI1P1
PTA2/KBI1P2
PTA3/KBI1P3
PTA4/KBI1P4
PTA5/KBI1P5
PTA6/KBI1P6
PTA7/KBI1P7
PTB0/AD1P0
PTB1/AD1P1
PTB2/AD1P2
PTB3/AD1P3
PTB4/AD1P4
PTB5/AD1P5
PTB6/AD1P6
PTB7/AD1P7
PTC0/TxD2
PTC1/RxD2
PTC2/SDA1
PTC3/SCL1
I/O AND
PERIPHERAL
INTERFACE TO
APPLICATION
SYSTEM
PTC4
PTC5
PTC6
PTC7
PTD0/TPM1CH0
PTD1/TPM1CH1
PTD2/TPM1CH2
PTD3/TPM2CH0
PTD4/TPM2CH1
PTD5/TPM2CH2
PTD6/TPM2CH3
PTD7/TPM2CH4
PTE0/TxD1
PTE1/RxD1
SS1
PTE2/
PTE3/MISO1
PTE4/MOSI1
PTE5/SPSCK1
PTE6
PTE7
Figure 2-5. Basic System Connections
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 27
Chapter 2 Pins and Connections
2.3.1 Power
VDD and VSS are the primary power supply pins for the MCU. This voltage source supplies power to all
I/O buffer circuitry and to an internal voltage regulator. The internal voltage regulator provides regulated
lower-voltage source to the CPU and other internal circuitry of the MCU.
Typically, application systems have two separate capacitors across the power pins. In this case, there
should be a bulk electrolytic capacitor, such as a 10-µF tantalum capacitor, to provide bulk charge storage
for the overall system and a 0.1-µF ceramic bypass capacitor located as close to the MCU power pins as
practical to suppress high-frequency noise.
V
DDAD
and V
are the analog power supply pins for the MCU. This voltage source supplies power to
SSAD
the ATD. A 0.1-µF ceramic bypass capacitor should be located as close to the MCU power pins as practical
to suppress high-frequency noise.
2.3.2 Oscillator
Out of reset, the MCU uses an internally generated clock (self-clocked mode — f
Self_reset
approximately equivalent to an 8-MHz crystal rate. This frequency source is used during reset startup and
can be enabled as the clock source for stop recovery to avoid the need for a long crystal startup delay. This
MCU also contains a trimmable internal clock generator (ICG) module that can be used to run the MCU.
For more information on the ICG, see Chapter 7, “Internal Clock Generator (ICG) Module.”
The oscillator in this MCU is a Pierce oscillator that can accommodate a crystal or ceramic resonator in
either of two frequency ranges selected by the RANGE bit in the ICGC1 register. Rather than a crystal or
ceramic resonator, an external oscillator can be connected to the EXTAL input pin, and the XTAL output
pin can be used as general I/O.
Refer to Figure 2-5 for the following discussion. R
(when used) and RF should be low-inductance
S
resistors such as carbon composition resistors. Wire-wound resistors, and some metal film resistors, have
too much inductance. C1 and C2 normally should be high-quality ceramic capacitors that are specifically
designed for high-frequency applications.
is used to provide a bias path to keep the EXTAL input in its linear range during crystal startup and its
R
F
value is not generally critical. Typical systems use 1 MΩ to 10 MΩ. Higher values are sensitive to humidity
and lower values reduce gain and (in extreme cases) could prevent startup.
) that is
C1 and C2 are typically in the 5-pF to 25-pF range and are chosen to match the requirements of a specific
crystal or resonator. Be sure to take into account printed circuit board (PCB) capacitance and MCU pin
capacitance when sizing C1 and C2. The crystal manufacturer typically specifies a load capacitance which
is the series combination of C1 and C2 which are usually the same size. As a first-order approximation,
use 10 pF as an estimate of combined pin and PCB capacitance for each oscillator pin (EXTAL and
XTAL).
2.3.3 Reset
RESET is a dedicated pin with a pullup device built in. It has input hysteresis, a high current output driver,
and no output slew rate control. Internal power-on reset and low-voltage reset circuitry typically make
external reset circuitry unnecessary. This pin is normally connected to the standard 6-pin background
MC9S08GB/GT Data Sheet, Rev. 2.3
28 Freescale Semiconductor
Recommended System Connections
debug connector so a development system can directly reset the MCU system. If desired, a manual external
reset can be added by supplying a simple switch to ground (pull reset pin low to force a reset).
Whenever any reset is initiated (whether from an external signal or from an internal system), the reset pin
is driven low for approximately 34 cycles of f
cycles of f
Self_reset
later. If reset was caused by an internal source such as low-voltage reset or watchdog
Self_reset
, released, and sampled again approximately 38
timeout, the circuitry expects the reset pin sample to return a logic 1. If the pin is still low at this sample
point, the reset is assumed to be from an external source. The reset circuitry decodes the cause of reset and
records it by setting a corresponding bit in the system control reset status register (SRS).
Never connect any significant capacitance to the reset pin because that would interfere with the circuit and
sequence that detects the source of reset. If an external capacitance prevents the reset pin from rising to a
valid logic 1 before the reset sample point, all resets will appear to be external resets.
2.3.4 Background / Mode Select (PTG0/BKGD/MS)
The background/mode select (BKGD/MS) shares its function with an I/O port pin. While in reset, the pin
functions as a mode select pin. Immediately after reset rises the pin functions as the background pin and
can be used for background debug communication. While functioning as a background/mode select pin,
the pin includes an internal pullup device, input hysteresis, a standard output driver, and no output slew
rate control. When used as an I/O port (PTG0) the pin is limited to output only.
If nothing is connected to this pin, the MCU will enter normal operating mode at the rising edge of reset.
If a debug system is connected to the 6-pin standard background debug header, it can hold BKGD/MS low
during the rising edge of reset which forces the MCU to active background mode.
The BKGD pin is used primarily for background debug controller (BDC) communications using a custom
protocol that uses 16 clock cycles of the target MCU’s BDC clock per bit time. The target MCU’s BDC
clock could be as fast as the bus clock rate, so there should never be any significant capacitance connected
to the BKGD/MS pin that could interfere with background serial communications.
Although the BKGD pin is a pseudo open-drain pin, the background debug communication protocol
provides brief, actively driven, high speedup pulses to ensure fast rise times. Small capacitances from
cables and the absolute value of the internal pullup device play almost no role in determining rise and fall
times on the BKGD pin.
2.3.5 General-Purpose I/O and Peripheral Ports
The remaining 55 pins are shared among general-purpose I/O and on-chip peripheral functions such as
timers and serial I/O systems. (Sixteen of these pins are not bonded out on the 48-pin package, twenty of
these pins are not bonded out on the 44-pin package, and twenty-two are not bonded out on the 42-pin
package.) Immediately after reset, all 55 of these pins are configured as high-impedance general-purpose
inputs with internal pullup devices disabled.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 29
Chapter 2 Pins and Connections
NOTE
To avoid extra current drain from floating input pins, the reset initialization
routine in the application program should either enable on-chip pullup
devices or change the direction of unused pins to outputs so the pins do not
float.
For information about controlling these pins as general-purpose I/O pins, see Chapter 6, “Parallel
Input/Output.” For information about how and when on-chip peripheral systems use these pins, refer to the
appropriate section from Table 2-1.
Table 2-1. Pin Sharing References
Port Pins
PTA7–PTA0 KBI1P7–KBI1P0 Chapter 2, “Pins and Connections”
PTB7–PTB0 AD1P7–AD1P0 Chapter 14, “Analog-to-Digital Converter (ATD) Module”
PTC7–PTC4 — Chapter 6, “Parallel Input/Output”
PTC3–PTC2 SCL1–SDA1 Chapter 13, “Inter-Integrated Circuit (IIC) Module”
PTC1–PTC0 RxD2–TxD2 Chapter 11, “Serial Communications Interface (SCI) Module”
PTD7–PTD3
PTD2–PTD0
PTE7–PTE6 — Chapter 6, “Parallel Input/Output”
PTE5
PTE4
PTE3
PTE2
PTE1–PTE0 RxD1–TxD1 Chapter 11, “Serial Communications Interface (SCI) Module”
PTF7–PTF0 — Chapter 6, “Parallel Input/Output”
Alternate
Function
TPM2CH4–
TPM2CH0
TPM1CH2–
TPM1CH0
SPSCK1
MISO1
MOSI1
SS1
Reference
Chapter 10, “Timer/PWM (TPM) Module”
Chapter 10, “Timer/PWM (TPM) Module”
Chapter 12, “Serial Peripheral Interface (SPI) Module”
1
PTG7–PTG3 — Chapter 6, “Parallel Input/Output”
PTG2–PTG1 EXTAL–XTAL Chapter 7, “Internal Clock Generator (ICG) Module”
PTG0 BKGD/MS Chapter 15, “Development Support”
1
See this section for information about modules that share these pins.
When an on-chip peripheral system is controlling a pin, data direction control bits still determine what is
read from port data registers even though the peripheral module controls the pin direction by controlling
the enable for the pin’s output buffer. See Chapter 6, “Parallel Input/Output” for details.
Pullup enable bits for each input pin control whether on-chip pullup devices are enabled whenever the pin
is acting as an input even if it is being controlled by an on-chip peripheral module. When the PTA7–PTA4
pins are controlled by the KBI module and are configured for rising-edge/high-level sensitivity, the pullup
enable control bits enable pulldown devices rather than pullup devices. Similarly, when IRQ is configured
MC9S08GB/GT Data Sheet, Rev. 2.3
30 Freescale Semiconductor
Recommended System Connections
as the IRQ input and is set to detect rising edges, the pullup enable control bit enables a pulldown device
rather than a pullup device.
2.3.6 Signal Properties Summary
Table 2-2 summarizes I/O pin characteristics. These characteristics are determined by the way the
common pin interfaces are hardwired to internal circuits.
Table 2-2. Signal Properties
Pin
Name
V
DD
V
SS
V
DDAD
V
SSAD
V
REFH
V
REFL
Dir
High Current
Pin
Output
Slew
Pull-Up
1
———
———
———
———
———
———
2
Comments
The 48-pin QFN package has two V
and V
SS2
.
RESET I/O Y N Y Pin contains integrated pullup.
IRQPE must be set to enable IRQ function.
IRQ does not have a clamp diode to V
not be driven above V
IRQ I — — Y
Pullup/pulldown active when IRQ pin function
enabled. Pullup forced on when IRQ enabled for
falling edges; pulldown forced on when IRQ enabled
for rising edges.
PTA0/KBI1P0 I/O N SWC SWC
PTA1/KBI1P1 I/O N SWC SWC
PTA2/KBI1P2 I/O N SWC SWC
PTA3/KBI1P3 I/O N SWC SWC
PTA4/KBI1P4 I/O N SWC SWC
PTA5/KBI1P5 I/O N SWC SWC
PTA6/KBI1P6 I/O N SWC SWC
PTA7/KBI1P7 I/O N SWC SWC
Pullup/pulldown active when KBI pin function
enabled. Pullup forced on when KBI1Px enabled for
falling edges; pulldown forced on when KBI1Px
enabled for rising edges.
PTB0/AD1P0 I/O N SWC SWC
PTB1/AD1P1 I/O N SWC SWC
PTB2/AD1P2 I/O N SWC SWC
PTB3/AD1P3 I/O N SWC SWC
PTB4/AD1P4 I/O N SWC SWC
PTB5/AD1P5 I/O N SWC SWC
PTB6/AD1P6 I/O N SWC SWC
PTB7/AD1P7 I/O N SWC SWC
PTC0/TxD2 I/O Y SWC SWC
PTC1/RxD2 I/O Y SWC SWC
When pin is configured for SCI function, pin is
configured for partial output drive.
PTC2/SDA1 I/O Y SWC SWC
PTC3/SCL1 I/O Y SWC SWC
DD
pins — V
SS
. IRQ should
DD
SS1
.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 31
Chapter 2 Pins and Connections
PTC4 I/O Y SWC SWC
PTC5 I/O Y SWC SWC Not available on 42-pin pkg
PTC6 I/O Y SWC SWC Not available on 42-pin pkg
PTC7 I/O Y SWC SWC Not available on 42- or 44-pin pkg
PTD0/TPM1CH0 I/O N SWC SWC
PTD1/TPM1CH1 I/O N SWC SWC
PTD2/TPM1CH2 I/O N SWC SWC Not available on 42- or 44-pin pkg
PTD3/TPM2CH0 I/O N SWC SWC
PTD4/TPM2CH1 I/O N SWC SWC
PTD5/TPM2CH2 I/O N SWC SWC Not available on 42-, 44-, or 48-pin pkg
PTD6/TPM2CH3 I/O N SWC SWC Not available on 42-, 44-, or 48-pin pkg
PTD7/TPM2CH4 I/O N SWC SWC Not available on 42-, 44-, or 48-pin pkg
PTE0/TxD1 I/O N SWC SWC
MC9S08GB/GT Data Sheet, Rev. 2.3
32 Freescale Semiconductor
Chapter 3 Modes of Operation
3.1 Introduction
The operating modes of the MC9S08GB/GT are described in this section. Entry into each mode, exit from
each mode, and functionality while in each of the modes are described.
3.2 Features
• Active background mode for code development
• Wait mode:
— CPU shuts down to conserve power
— System clocks running
— Full voltage regulation maintained
• Stop modes:
— System clocks stopped; voltage regulator in standby
— Stop1 — Full power down of internal circuits for maximum power savings
— Stop2 — Partial power down of internal circuits, RAM contents retained
— Stop3 — All internal circuits powered for fast recovery
3.3 Run Mode
This is the normal operating mode for the MC9S08GB/GT. This mode is selected when the BKGD/MS
pin is high at the rising edge of reset. In this mode, the CPU executes code from internal memory with
execution beginning at the address fetched from memory at $FFFE:$FFFF after reset.
3.4 Active Background Mode
The active background mode functions are managed through the background debug controller (BDC) in
the HCS08 core. The BDC, together with the on-chip debug module (DBG), provide the means for
analyzing MCU operation during software development.
Active background mode is entered in any of five ways:
• When the BKGD/MS pin is low at the rising edge of reset
• When a BACKGROUND command is received through the BKGD pin
• When a BGND instruction is executed
• When encountering a BDC breakpoint
• When encountering a DBG breakpoint
After entering active background mode, the CPU is held in a suspended state waiting for serial background
commands rather than executing instructions from the user’s application program.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 33
Chapter 3 Modes of Operation
Background commands are of two types:
• Non-intrusive commands, defined as commands that can be issued while the user program is
running. Non-intrusive commands can be issued through the BKGD pin while the MCU is in run
mode; non-intrusive commands can also be executed while the MCU is in the active background
mode. Non-intrusive commands include:
— Memory access commands
— Memory-access-with-status commands
— BDC register access commands
— The BACKGROUND command
• Active background commands, which can be executed only while the MCU is in active background
mode. Active background commands include commands to:
— Read or write CPU registers
— Trace one user program instruction at a time
— Leave active background mode to return to the user’s application program (GO)
The active background mode is used to program a bootloader or user application program into the FLASH
program memory before the MCU is operated in run mode for the first time. When the MC9S08GB/GT is
shipped from the Freescale Semiconductor factory, the FLASH program memory is erased by default
unless specifically noted so there is no program that could be executed in run mode until the FLASH
memory is initially programmed. The active background mode can also be used to erase and reprogram
the FLASH memory after it has been previously programmed.
For additional information about the active background mode, refer to Chapter 15, “Development
Support.”
3.5 Wait Mode
Wait mode is entered by executing a WAIT instruction. Upon execution of the WAIT instruction, the CPU
enters a low-power state in which it is not clocked. The I bit in CCR is cleared when the CPU enters the
wait mode, enabling interrupts. When an interrupt request occurs, the CPU exits the wait mode and
resumes processing, beginning with the stacking operations leading to the interrupt service routine.
While the MCU is in wait mode, there are some restrictions on which background debug commands can
be used. Only the BACKGROUND command and memory-access-with-status commands are available
when the MCU is in wait mode. The memory-access-with-status commands do not allow memory access,
but they report an error indicating that the MCU is in either stop or wait mode. The BACKGROUND
command can be used to wake the MCU from wait mode and enter active background mode.
3.6 Stop Modes
One of three stop modes is entered upon execution of a STOP instruction when the STOPE bit in the
system option register is set. In all stop modes, all internal clocks are halted. If the STOPE bit is not set
when the CPU executes a STOP instruction, the MCU will not enter any of the stop modes and an illegal
opcode reset is forced. The stop modes are selected by setting the appropriate bits in SPMSC2.
MC9S08GB/GT Data Sheet, Rev. 2.3
34 Freescale Semiconductor
Table 3-1 summarizes the behavior of the MCU in each of the stop modes.
Table 3-1. Stop Mode Behavior
CPU, Digital
Mode PDC PPDC
Peripherals,
FLASH
RAM ICG ATD Regulator I/O Pins RTI
Stop Modes
Stop1 1 0 Off Off Off Disabled
Stop2 1 1 Off Standby Off Disabled Standby States
Stop3 0 Don’t
care
1
Either ATD stop mode or power-down mode depending on the state of ATDPU.
2
Crystal oscillator can be configured to run in stop3. Please see the ICG registers.
Standby Standby Off
2
Disabled Standby States
1
Off Reset Off
Optionally on
held
Optionally on
held
3.6.1 Stop1 Mode
The stop1 mode provides the lowest possible standby power consumption by causing the internal circuitry
of the MCU to be powered down. Stop1 can be entered only if the LVD circuit is not enabled in stop modes
(either LVDE or LVDSE not set).
When the MCU is in stop1 mode, all internal circuits that are powered from the voltage regulator are turned
off. The voltage regulator is in a low-power standby state, as is the ATD.
Exit from stop1 is performed by asserting either of the wake-up pins on the MCU:
always an active low input when the MCU is in stop1, regardless of how it was configured before entering
stop1.
Entering stop1 mode automatically asserts LVD. Stop1 cannot be exited until V
must rise above the LVI rearm voltage).
RESET or IRQ. IRQ is
DD
>V
LVDH/L
rising (V
DD
Upon wake-up from stop1 mode, the MCU will start up as from a power-on reset (POR). The CPU will
take the reset vector.
3.6.2 Stop2 Mode
The stop2 mode provides very low standby power consumption and maintains the contents of RAM and
the current state of all of the I/O pins. Stop2 can be entered only if the LVD circuit is not enabled in stop
modes (either LVDE or LVDSE not set).
Before entering stop2 mode, the user must save the contents of the I/O port registers, as well as any other
memory-mapped registers they want to restore after exit of stop2, to locations in RAM. Upon exit of stop2,
these values can be restored by user software before pin latches are opened.
When the MCU is in stop2 mode, all internal circuits that are powered from the voltage regulator are turned
off, except for the RAM. The voltage regulator is in a low-power standby state, as is the ATD. Upon entry
into stop2, the states of the I/O pins are latched. The states are held while in stop2 mode and after exiting
stop2 mode until a 1 is written to PPDACK in SPMSC2.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 35
Chapter 3 Modes of Operation
Exit from stop2 is performed by asserting either of the wake-up pins: RESET or IRQ, or by an RTI
interrupt. IRQ is always an active low input when the MCU is in stop2, regardless of how it was configured
before entering stop2.
Upon wake-up from stop2 mode, the MCU will start up as from a power-on reset (POR) except pin states
remain latched. The CPU will take the reset vector. The system and all peripherals will be in their default
reset states and must be initialized.
After waking up from stop2, the PPDF bit in SPMSC2 is set. This flag may be used to direct user code to
go to a stop2 recovery routine. PPDF remains set and the I/O pin states remain latched until a 1 is written
to PPDACK in SPMSC2.
To maintain I/O state for pins that were configured as general-purpose I/O, the user must restore the
contents of the I/O port registers, which have been saved in RAM, to the port registers before writing to
the PPDACK bit. If the port registers are not restored from RAM before writing to PPDACK, then the
register bits will assume their reset states when the I/O pin latches are opened and the I/O pins will switch
to their reset states.
For pins that were configured as peripheral I/O, the user must reconfigure the peripheral module that
interfaces to the pin before writing to the PPDACK bit. If the peripheral module is not enabled before
writing to PPDACK, the pins will be controlled by their associated port control registers when the I/O
latches are opened.
3.6.3 Stop3 Mode
Upon entering the stop3 mode, all of the clocks in the MCU, including the oscillator itself, are halted. The
ICG is turned off, the ATD is disabled, and the voltage regulator is put in standby. The states of all of the
internal registers and logic, as well as the RAM content, are maintained. The I/O pin states are not latched
at the pin as in stop2. Instead they are maintained by virtue of the states of the internal logic driving the
pins being maintained.
Exit from stop3 is performed by asserting
RESET, an asynchronous interrupt pin, or through the real-time
interrupt. The asynchronous interrupt pins are the IRQ or KBI pins.
If stop3 is exited by means of the
RESET pin, then the MCU will be reset and operation will resume after
taking the reset vector. Exit by means of an asynchronous interrupt or the real-time interrupt will result in
the MCU taking the appropriate interrupt vector.
A separate self-clocked source (≈1 kHz) for the real-time interrupt allows a wakeup from stop2 or stop3
mode with no external components. When RTIS2:RTIS1:RTIS0 = 0:0:0, the real-time interrupt function
and this 1-kHz source are disabled. Power consumption is lower when the 1-kHz source is disabled, but in
that case the real-time interrupt cannot wake the MCU from stop.
3.6.4 Active BDM Enabled in Stop Mode
Entry into the active background mode from run mode is enabled if the ENBDM bit in BDCSCR is set.
This register is described in the Chapter 15, “Development Support,” section of this data sheet. If ENBDM
is set when the CPU executes a STOP instruction, the system clocks to the background debug logic remain
active when the MCU enters stop mode so background debug communication is still possible. In addition,
MC9S08GB/GT Data Sheet, Rev. 2.3
36 Freescale Semiconductor
Stop Modes
the voltage regulator does not enter its low-power standby state but maintains full internal regulation. If
the user attempts to enter either stop1 or stop2 with ENBDM set, the MCU will instead enter stop3.
Most background commands are not available in stop mode. The memory-access-with-status commands
do not allow memory access, but they report an error indicating that the MCU is in either stop or wait
mode. The BACKGROUND command can be used to wake the MCU from stop and enter active
background mode if the ENBDM bit is set. After the device enters background debug mode, all
background commands are available. The table below summarizes the behavior of the MCU in stop when
entry into the background debug mode is enabled.
Table 3-2. BDM Enabled Stop Mode Behavior
CPU, Digital
Mode PDC PPDC
Stop3 Don’t
care
1
Either ATD stop mode or power-down mode depending on the state of ATDPU.
Don’t
care
Peripherals,
FLASH
Standby Standby Active Disabled
RAM ICG ATD Regulator I/O Pins RTI
1
Active States
Optionally on
held
3.6.5 LVD Enabled in Stop Mode
The LVD system is capable of generating either an interrupt or a reset when the supply voltage drops below
the LVD voltage. If the LVD is enabled in stop by setting the LVDE and the LVDSE bits in SPMSC1 when
the CPU executes a STOP instruction, then the voltage regulator remains active during stop mode. If the
user attempts to enter either stop1 or stop2 with the LVD enabled for stop (LVDSE = 1), the MCU will
instead enter stop3. The table below summarizes the behavior of the MCU in stop when the LVD is
enabled.
Table 3-3. LVD Enabled Stop Mode Behavior
CPU, Digital
Mode PDC PPDC
Stop3 Don’t
care
1
Either ATD stop mode or power-down mode depending on the state of ATDPU.
Don’t
care
Peripherals,
FLASH
Standby Standby Standby Disabled
RAM ICG ATD Regulator I/O Pins RTI
1
Active States
Optionally on
held
3.6.6 On-Chip Peripheral Modules in Stop Modes
When the MCU enters any stop mode, system clocks to the internal peripheral modules are stopped. Even
in the exception case (ENBDM = 1), where clocks to the background debug logic continue to operate,
clocks to the peripheral systems are halted to reduce power consumption. Refer to Section 3.6.1, “Stop1
Mode,” Section 3.6.2, “Stop2 Mode,” and Section 3.6.3, “Stop3 Mode,” for specific information on system
behavior in stop modes.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 37
Chapter 3 Modes of Operation
I/O Pins
• All I/O pin states remain unchanged when the MCU enters stop3 mode.
• If the MCU is configured to go into stop2 mode, all I/O pins states are latched before entering stop.
• If the MCU is configured to go into stop1 mode, all I/O pins are forced to their default reset state
upon entry into stop.
Memory
• All RAM and register contents are preserved while the MCU is in stop3 mode.
• All registers will be reset upon wake-up from stop2, but the contents of RAM are preserved and
pin states remain latched until the PPDACK bit is written. The user may save any memory-mapped
register data into RAM before entering stop2 and restore the data upon exit from stop2.
• All registers will be reset upon wake-up from stop1 and the contents of RAM are not preserved.
The MCU must be initialized as upon reset. The contents of the FLASH memory are nonvolatile
and are preserved in any of the stop modes.
ICG — In stop3 mode, the ICG enters its low-power standby state. Either the oscillator or the internal
reference may be kept running when the ICG is in standby by setting the appropriate control bit. In both
stop2 and stop1 modes, the ICG is turned off. Neither the oscillator nor the internal reference can be kept
running in stop2 or stop1, even if enabled within the ICG module.
TPM — When the MCU enters stop mode, the clock to the TPM1 and TPM2 modules stop. The modules
halt operation. If the MCU is configured to go into stop2 or stop1 mode, the TPM modules will be reset
upon wake-up from stop and must be reinitialized.
ATD — When the MCU enters stop mode, the ATD will enter a low-power standby state
. No conversion
operation will occur while in stop. If the MCU is configured to go into stop2 or stop1 mode, the ATD will
be reset upon wake-up from stop and must be reinitialized.
KBI — During stop3, the KBI pins that are enabled continue to function as interrupt sources that are
capable of waking the MCU from stop3. The KBI is disabled in stop1 and stop2 and must be reinitialized
after waking up from either of these modes.
SCI — When the MCU enters stop mode, the clocks to the SCI1 and SCI2 modules stop. The modules
halt operation. If the MCU is configured to go into stop2 or stop1 mode, the SCI modules will be reset
upon wake-up from stop and must be reinitialized.
SPI — When the MCU enters stop mode, the clocks to the SPI module stop. The module halts operation.
If the MCU is configured to go into stop2 or stop1 mode, the SPI module will be reset upon wake-up from
stop and must be reinitialized.
IIC — When the MCU enters stop mode, the clocks to the IIC module stops. The module halts operation.
If the MCU is configured to go into stop2 or stop1 mode, the IIC module will be reset upon wake-up from
stop and must be reinitialized.
Voltage Regulator — The voltage regulator enters a low-power standby state when the MCU enters any
of the stop modes unless the LVD is enabled in stop mode or BDM is enabled.
MC9S08GB/GT Data Sheet, Rev. 2.3
38 Freescale Semiconductor
Chapter 4 Memory
4.1 MC9S08GB/GT Memory Map
As shown in Figure 4-1, on-chip memory in the MC9S08GB/GT series of MCUs consists of RAM,
FLASH program memory for nonvolatile data storage, plus I/O and control/status registers. The registers
are divided into three groups:
• Direct-page registers ($0000 through $007F)
• High-page registers ($1800 through $182B)
• Nonvolatile registers ($FFB0 through $FFBF)
DIRECT PAGE REGISTERS
RAM
4096 BYTES
FLASH
1920 BYTES
HIGH PAGE REGISTERS
FLASH
59348 BYTES
$0000
$007F
$0080
$107F
$1080
$17FF
$1800
$182B
$182C
DIRECT PAGE REGISTERS
RAM
2048 BYTES
UNIMPLEMENTED
3968 BYTES
HIGH PAGE REGISTERS
UNIMPLEMENTED
26580 BYTES
FLASH
32768 BYTES
$0000
$007F
$0080
$087F
$0880
$17FF
$1800
$182B
$182C
$7FFF
$8000
DIRECT PAGE REGISTERS
RAM 1024 BYTES
UNIMPLEMENTED
4992 BYTES
HIGH PAGE REGISTERS
UNIMPLEMENTED
42964 BYTES
FLASH
$0000
$007F
$0080
$047F
$0480
$17FF
$1800
$182B
$182C
$BFFF
$C000
16384 BYTES
$FFFF
MC9S08GB60/MC9S08GT60 MC9S08GB32/MC9S08GT32
$FFFF
MC9S08GT16
$FFFF
Figure 4-1. MC9S08GB/GT Memory Map
4.1.1 Reset and Interrupt Vector Assignments
Table 4-1 shows address assignments for reset and interrupt vectors. The vector names shown in this table
are the labels used in the Freescale-provided equate file for the MC9S08GB/GT. For more details about
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 39
Chapter 4 Memory
resets, interrupts, interrupt priority, and local interrupt mask controls, refer to Chapter 5, “Resets,
Interrupts, and System Configuration.”
Table 4-1. Reset and Interrupt Vectors
Address
(High/Low)
$FFC0:FFC1
Unused Vector Space
(available for user program)
$FFCA:FFCB
$FFCC:FFCD RTI Vrti
$FFCE:FFCF IIC Viic1
$FFD0:FFD1 ATD Conversion Vatd1
$FFD2:FFD3 Keyboard Vkeyboard1
$FFD4:FFD5 SCI2 Transmit Vsci2tx
$FFD6:FFD7 SCI2 Receive Vsci2rx
$FFD8:FFD9 SCI2 Error Vsci2err
$FFDA:FFDB SCI1 Transmit Vsci1tx
$FFDC:FFDD SCI1 Receive Vsci1rx
$FFDE:FFDF SCI1 Error Vsci1err
$FFE0:FFE1 SPI Vspi1
$FFE2:FFE3 TPM2 Overflow Vtpm2ovf
$FFE4:FFE5 TPM2 Channel 4 Vtpm2ch4
$FFE6:FFE7 TPM2 Channel 3 Vtpm2ch3
$FFE8:FFE9 TPM2 Channel 2 Vtpm2ch2
$FFEA:FFEB TPM2 Channel 1 Vtpm2ch1
$FFEC:FFED TPM2 Channel 0 Vtpm2ch0
$FFEE:FFEF TPM1 Overflow Vtpm1ovf
$FFF0:FFF1 TPM1 Channel 2 Vtpm1ch2
$FFF2:FFF3 TPM1 Channel 1 Vtpm1ch1
$FFF4:FFF5 TPM1 Channel 0 Vtpm1ch0
$FFF6:FFF7 ICG Vicg
$FFF8:FFF9 Low Voltage Detect Vlvd
$FFFA:FFFB IRQ Virq
$FFFC:FFFD SWI Vswi
$FFFE:FFFF Reset Vreset
Vector Vector Name
MC9S08GB/GT Data Sheet, Rev. 2.3
40 Freescale Semiconductor
Register Addresses and Bit Assignments
4.2 Register Addresses and Bit Assignments
The registers in the MC9S08GB/GT are divided into these three groups:
• Direct-page registers are located in the first 128 locations in the memory map, so they are
accessible with efficient direct addressing mode instructions.
• High-page registers are used much less often, so they are located above $1800 in the memory map.
This leaves more room in the direct page for more frequently used registers and variables.
• The nonvolatile register area consists of a block of 16 locations in FLASH memory at
$FFB0–$FFBF.
Nonvolatile register locations include:
— Three values which are loaded into working registers at reset
— An 8-byte backdoor comparison key which optionally allows a user to gain controlled access
to secure memory
Because the nonvolatile register locations are FLASH memory, they must be erased and
programmed like other FLASH memory locations.
Direct-page registers can be accessed with efficient direct addressing mode instructions. Bit manipulation
instructions can be used to access any bit in any direct-page register. Table 4-2 is a summary of all
user-accessible direct-page registers and control bits.
The direct page registers in Table 4-2 can use the more efficient direct addressing mode which only
requires the lower byte of the address. Because of this, the lower byte of the address in column one is
shown in bold text. In Table 4-3 and Table 4-4 the whole address in column one is shown in bold. In
Table 4-2, Table 4-3, and Table 4-4, the register names in column two are shown in bold to set them apart
from the bit names to the right. Cells that are not associated with named bits are shaded. A shaded cell with
a 0 indicates this unused bit always reads as a 0. Shaded cells with dashes indicate unused or reserved bit
locations that could read as 1s or 0s.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 41
Chapter 4 Memory
Table 4-2. Direct-Page Register Summary (Sheet 1 of 3)
Address Register Name Bit 7 654321Bit 0
$0000 PTAD PTAD7 PTAD6 PTAD5 PTAD4 PTAD3 PTAD2 PTAD1 PTAD0
$0001 PTAPE PTAPE7 PTAPE6 PTAPE5 PTAPE4 PTAPE3 PTAPE2 PTAPE1 PTAPE0
$0002 PTASE PTASE7 PTASE6 PTASE5 PTASE4 PTASE3 PTASE2 PTASE1 PTASE0
$0003 PTADD PTADD7 PTADD6 PTADD5 PTADD4 PTADD3 PTADD2 PTADD1 PTADD0
$0004 PTBD PTBD7 PTBD6 PTBD5 PTBD4 PTBD3 PTBD2 PTBD1 PTBD0
$0005 PTBPE PTBPE7 PTBPE6 PTBPE5 PTBPE4 PTBPE3 PTBPE2 PTBPE1 PTBPE0
$0006 PTBSE PTBSE7 PTBSE6 PTBSE5 PTBSE4 PTBSE3 PTBSE2 PTBSE1 PTBSE0
$0007 PTBDD PTBDD7 PTBDD6 PTBDD5 PTBDD4 PTBDD3 PTBDD2 PTBDD1 PTBDD0
$0008 PTCD PTCD7 PTCD6 PTCD5 PTCD4 PTCD3 PTCD2 PTCD1 PTCD0
$0009 PTCPE PTCPE7 PTCPE6 PTCPE5 PTCPE4 PTCPE3 PTCPE2 PTCPE1 PTCPE0
$000A PTCSE PTCSE7 PTCSE6 PTCSE5 PTCSE4 PTCSE3 PTCSE2 PTCSE1 PTCSE0
$000B PTCDD PTCDD7 PTCDD6 PTCDD5 PTCDD4 PTCDD3 PTCDD2 PTCDD1 PTCDD0
$000C PTDD PTDD7 PTDD6 PTDD5 PTDD4 PTDD3 PTDD2 PTDD1 PTDD0
$000D PTDPE PTDPE7 PTDPE6 PTDPE5 PTDPE4 PTDPE3 PTDPE2 PTDPE1 PTDPE0
$000E PTDSE PTDSE7 PTDSE6 PTDSE5 PTDSE4 PTDSE3 PTDSE2 PTDSE1 PTDSE0
$000F PTDDD PTDDD7 PTDDD6 PTDDD5 PTDDD4 PTDDD3 PTDDD2 PTDDD1 PTDDD0
$0010 PTED PTED7 PTED6 PTED5 PTED4 PTED3 PTED2 PTED1 PTED0
$0011 PTEPE PTEPE7 PTEPE6 PTEPE5 PTEPE4 PTEPE3 PTEPE2 PTEPE1 PTEPE0
$0012 PTESE PTESE7 PTESE6 PTESE5 PTESE4 PTESE3 PTESE2 PTESE1 PTESE0
$0013 PTEDD PTEDD7 PTEDD6 PTEDD5 PTEDD4 PTEDD3 PTEDD2 PTEDD1 PTEDD0
$0014 IRQSC 0 0 IRQEDG IRQPE IRQF IRQACK IRQIE IRQMOD
$0015 Reserved — — — — — — — —
$0016 KBI1SC KBEDG7 KBEDG6 KBEDG5 KBEDG4 KBF KBACK KBIE KBIMOD
$0017 KBI1PE KBIPE7 KBIPE6 KBIPE5 KBIPE4 KBIPE3 KBIPE2 KBIPE1 KBIPE0
$0018 SCI1BDH 0 0 0 SBR12 SBR11 SBR10 SBR9 SBR8
$0019 SCI1BDL SBR7 SBR6 SBR5 SBR4 SBR3 SBR2 SBR1 SBR0
$001A SCI1C1 LOOPS SCISWAI RSRC M WAKE ILT PE PT
$001B SCI1C2 TIE TCIE RIE ILIE TE RE RWU SBK
$001C SCI1S1 TDRE TC RDRF IDLE OR NF FE PF
$001D SCI1S2 0 0 0 0 0 0 0 RAF
$001E SCI1C3 R8 T8 TXDIR 0 ORIE NEIE FEIE PEIE
$001F SCI1D Bit 7 654321Bit 0
$0020 SCI2BDH 0 0 0 SBR12 SBR11 SBR10 SBR9 SBR8
$0021 SCI2BDL SBR7 SBR6 SBR5 SBR4 SBR3 SBR2 SBR1 SBR0
$0022 SCI2C1 LOOPS SCISWAI RSRC M WAKE ILT PE PT
$0023 SCI2C2 TIE TCIE RIE ILIE TE RE RWU SBK
$0024 SCI2S1 TDRE TC RDRF IDLE OR NF FE PF
$0025 SCI2S2 0 0 0 0 0 0 0 RAF
$0026 SCI2C3 R8 T8 TXDIR 0 ORIE NEIE FEIE PEIE
$0027 SCI2D Bit 7 654321Bit 0
MC9S08GB/GT Data Sheet, Rev. 2.3
42 Freescale Semiconductor
Register Addresses and Bit Assignments
Table 4-2. Direct-Page Register Summary (Sheet 2 of 3)
Address Register Name Bit 7 654321Bit 0
$0028 SPI1C1 SPIE SPE SPTIE MSTR CPOL CPHA SSOE LSBFE
$0029 SPI1C2 0 0 0 MODFEN BIDIROE 0 SPISWAI SPC0
$002A SPI1BR 0 SPPR2 SPPR1 SPPR0 0 SPR2 SPR1 SPR0
$002B SPI1S SPRF 0 SPTEF MODF 0 0 0 0
$002C Reserved 0 0 0 0 0 0 0 0
$002D SPI1D Bit 7 654321Bit 0
$002E Reserved 0 0 0 0 0 0 0 0
$002F Reserved 0 0 0 0 0 0 0 0
$0030 TPM1SC TOF TOIE CPWMS CLKSB CLKSA PS2 PS1 PS0
$0031 TPM1CNTH Bit 15 14 13 12 11 10 9 Bit 8
$0032 TPM1CNTL Bit 7 654321Bit 0
$0033 TPM1MODH Bit 15 14 13 12 11 10 9 Bit 8
$0034 TPM1MODL Bit 7 654321Bit 0
$0035 TPM1C0SC CH0F CH0IE MS0B MS0A ELS0B ELS0A 0 0
$0036 TPM1C0VH Bit 15 14 13 12 11 10 9 Bit 8
$0037 TPM1C0VL Bit 7 654321Bit 0
$0038 TPM1C1SC CH1F CH1IE MS1B MS1A ELS1B ELS1A 0 0
$0039 TPM1C1VH Bit 15 14 13 12 11 10 9 Bit 8
$003A TPM1C1VL Bit 7 654321Bit 0
$003B TPM1C2SC CH2F CH2IE MS2B MS2A ELS2B ELS2A 0 0
$003C TPM1C2VH Bit 15 14 13 12 11 10 9 Bit 8
$003D TPM1C2VL Bit 7 654321Bit 0
$003E–
$003F
Reserved
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
$0040 PTFD PTFD7 PTFD6 PTFD5 PTFD4 PTFD3 PTFD2 PTFD1 PTFD0
$0041 PTFPE PTFPE7 PTFPE6 PTFPE5 PTFPE4 PTFPE3 PTFPE2 PTFPE1 PTFPE0
$0042 PTFSE PTFSE7 PTFSE6 PTFSE5 PTFSE4 PTFSE3 PTFSE2 PTFSE1 PTFSE0
$0043 PTFDD PTFDD7 PTFDD6 PTFDD5 PTFDD4 PTFDD3 PTFDD2 PTFDD1 PTFDD0
$0044 PTGD PTGD7 PTGD6 PTGD5 PTGD4 PTGD3 PTGD2 PTGD1 PTGD0
$0045 PTGPE PTGPE7 PTGPE6 PTGPE5 PTGPE4 PTGPE3 PTGPE2 PTGPE1 PTGPE0
$0046 PTGSE PTGSE7 PTGSE6 PTGSE5 PTGSE4 PTGSE3 PTGSE2 PTGSE1 PTGSE0
$0047 PTGDD PTGDD7 PTGDD6 PTGDD5 PTGDD4 PTGDD3 PTGDD2 PTGDD1 PTGDD0
$0048 ICGC1 0 RANGE REFS CLKS OSCSTEN 0* 0
$0049 ICGC2 LOLRE MFD LOCRE RFD
$004A ICGS1 CLKST REFST LOLS LOCK LOCS ERCS ICGIF
$004B ICGS2 0 0 0 0 0 0 0 DCOS
$004C ICGFLTU 0 0 0 0 FLT
$004D ICGFLTL FLT
$004E ICGTRM TRIM
* This bit is reserved for Freescale Semiconductor internal use only. Always write a 0 to this bit.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 43
Chapter 4 Memory
Table 4-2. Direct-Page Register Summary (Sheet 3 of 3)
Address Register Name Bit 7 654321Bit 0
$004F Reserved 0 0 0 0 0 0 0 0
$0050 ATD1C ATDPU DJM RES8 SGN PRS
$0051 ATD1SC CCF ATDIE ATDCO ATDCH
$0052 ATD1RH Bit 7 654321Bit 0
$0053 ATD1RL Bit 7 654321Bit 0
$0054 ATD1PE ATDPE7 ATDPE6 ATDPE5 ATDPE4 ATDPE3 ATDPE2 ATDPE1 ATDPE0
$0055–
$0057
Reserved
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
$0058 IIC1A ADDR 0
$0059 IIC1F MULT ICR
$005A IIC1C IICEN IICIE MST TX TXAK RSTA 0 0
$005B IIC1S TCF IAAS BUSY ARBL 0 SRW IICIF RXAK
$005C IIC1D DATA
$005D–
$005F
Reserved
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
$0060 TPM2SC TOF TOIE CPWMS CLKSB CLKSA PS2 PS1 PS0
$0061 TPM2CNTH Bit 15 14 13 12 11 10 9 Bit 8
$0062 TPM2CNTL Bit 7 654321Bit 0
$0063 TPM2MODH Bit 15 14 13 12 11 10 9 Bit 8
$0064 TPM2MODL Bit 7 654321Bit 0
$0065 TPM2C0SC CH0F CH0IE MS0B MS0A ELS0B ELS0A 0 0
$0066 TPM2C0VH Bit 15 14 13 12 11 10 9 Bit 8
$0067 TPM2C0VL Bit 7 654321Bit 0
$0068 TPM2C1SC CH1F CH1IE MS1B MS1A ELS1B ELS1A 0 0
$0069 TPM2C1VH Bit 15 14 13 12 11 10 9 Bit 8
$006A TPM2C1VL Bit 7 654321Bit 0
$006B TPM2C2SC CH2F CH2IE MS2B MS2A ELS2B ELS2A 0 0
$006C TPM2C2VH Bit 15 14 13 12 11 10 9 Bit 8
$006D TPM2C2VL Bit 7 654321Bit 0
$006E TPM2C3SC CH3F CH3IE MS3B MS3A ELS3B ELS3A 0 0
$006F TPM2C3VH Bit 15 14 13 12 11 10 9 Bit 8
$0070 TPM2C3VL Bit 7 654321Bit 0
$0071 TPM2C4SC CH4F CH4IE MS4B MS4A ELS4B ELS4A 0 0
$0072 TPM2C4VH Bit 15 14 13 12 11 10 9 Bit 8
$0073 TPM2C4VL Bit 7 654321Bit 0
$0074–
$007F
Reserved
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
MC9S08GB/GT Data Sheet, Rev. 2.3
44 Freescale Semiconductor
Register Addresses and Bit Assignments
High-page registers, shown in Table 4-3, are accessed much less often than other I/O and control registers
so they have been located outside the direct addressable memory space, starting at $1800.
Table 4-3. High-Page Register Summary
Address Register Name Bit 7 654321Bit 0
$1800 SRS POR PIN COP ILOP 0 ICG LVD 0
$1801 SBDFR 0 0 0 0 0 0 0 BDFR
$1802 SOPT COPE COPT STOPE — 0 0 BKGDPE —
$1803 –
$1805
$1806 SDIDH REV3 REV2 REV1 REV0 ID11 ID10 ID9 ID8
$1807 SDIDL ID7 ID6 ID5 ID4 ID3 ID2 ID1 ID0
$1808 SRTISC RTIF RTIACK RTICLKS RTIE 0 RTIS2 RTIS1 RTIS0
$1809 SPMSC1 LVDF LVDACK LVDIE LVDRE LVDSE LVDE 0 0
$180A SPMSC2 LVWF LVWACK LVDV LVWV PPDF PPDACK PDC PPDC
$180B–
$180F
$1810 DBGCAH Bit 15 14 13 12 11 10 9 Bit 8
$1811 DBGCAL Bit 7 654321Bit 0
$1812 DBGCBH Bit 15 14 13 12 11 10 9 Bit 8
$1813 DBGCBL Bit 7 654321Bit 0
$1814 DBGFH Bit 15 14 13 12 11 10 9 Bit 8
$1815 DBGFL Bit 7 654321Bit 0
$1816 DBGC DBGEN ARM TAG BRKEN RWA RWAEN RWB RWBEN
$1817 DBGT TRGSEL BEGIN 0 0 TRG3 TRG2 TRG1 TRG0
$1818 DBGS AF BF ARMF 0 CNT3 CNT2 CNT1 CNT0
$1819–
$181F
$1820 FCDIV DIVLD PRDIV8 DIV5 DIV4 DIV3 DIV2 DIV1 DIV0
$1821 FOPT KEYEN FNORED 0 0 0 0 SEC01 SEC00
$1822 Reserved — — — — — — — —
$1823 FCNFG 0 0 KEYACC 0 0 0 0 0
$1824 FPROT FPOPEN FPDIS FPS2 FPS1 FPS0 0 0 0
$1825 FSTAT FCBEF FCCF FPVIOL FACCERR 0 FBLANK 0 0
$1826 FCMD FCMD7 FCMD6 FCMD5 FCMD4 FCMD3 FCMD2 FCMD1 FCMD0
$1827–
$182B
Reserved
Reserved
Reserved
Reserved
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Nonvolatile FLASH registers, shown in Table 4-4, are located in the FLASH memory. These registers
include an 8-byte backdoor key which optionally can be used to gain access to secure memory resources.
During reset events, the contents of NVPROT and NVOPT in the nonvolatile register area of the FLASH
memory are transferred into corresponding FPROT and FOPT working registers in the high-page registers
to control security and block protection options.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 45
Chapter 4 Memory
Table 4-4. Nonvolatile Register Summary
Address Register Name Bit 7 654321Bit 0
$FFB0 –
$FFB7
$FFB8 –
$FFBC
$FFBD NVPROT FPOPEN FPDIS FPS2 FPS1 FPS0 0 0 0
$FFBE Reserved
$FFBF NVOPT KEYEN FNORED 0 0 0 0 SEC01 SEC00
1
This location is used to store the factory trim value for the ICG.
NVBACKKEY
Reserved —
—
1
— — — — — — — —
—
—
—
—
8-Byte Comparison Key
—
—
—
—
—
—
—
—
—
—
Provided the key enable (KEYEN) bit is 1, the 8-byte comparison key can be used to temporarily
disengage memory security. This key mechanism can be accessed only through user code running in secure
memory. (A security key cannot be entered directly through background debug commands.) This security
key can be disabled completely by programming the KEYEN bit to 0. If the security key is disabled, the
only way to disengage security is by mass erasing the FLASH if needed (normally through the background
debug interface) and verifying that FLASH is blank. To avoid returning to secure mode after the next reset,
program the security bits (SEC01:SEC00) to the unsecured state (1:0).
4.3 RAM
The MC9S08GB/GT includes static RAM. The locations in RAM below $0100 can be accessed using the
more efficient direct addressing mode, and any single bit in this area can be accessed with the bit
manipulation instructions (BCLR, BSET, BRCLR, and BRSET). Locating the most frequently accessed
program variables in this area of RAM is preferred.
The RAM retains data when the MCU is in low-power wait, stop2, or stop3 mode. At power-on or after
wakeup from stop1, the contents of RAM are uninitialized. RAM data is unaffected by any reset provided
that the supply voltage does not drop below the minimum value for RAM retention.
For compatibility with older M68HC05 MCUs, the HCS08 resets the stack pointer to $00FF. In the
MC9S08GB/GT, it is usually best to re-initialize the stack pointer to the top of the RAM so the direct page
RAM can be used for frequently accessed RAM variables and bit-addressable program variables. Include
the following 2-instruction sequence in your reset initialization routine (where RamLast is equated to the
highest address of the RAM in the Freescale-provided equate file).
LDHX #RamLast+1 ;point one past RAM
TXS ;SP<-(H:X-1)
When security is enabled, the RAM is considered a secure memory resource and is not accessible through
BDM or through code executing from non-secure memory. See Section 4.5, “Security” for a detailed
description of the security feature.
4.4 FLASH
The FLASH memory is intended primarily for program storage. In-circuit programming allows the
operating program to be loaded into the FLASH memory after final assembly of the application product.
MC9S08GB/GT Data Sheet, Rev. 2.3
46 Freescale Semiconductor
FLASH
It is possible to program the entire array through the single-wire background debug interface. Because no
special voltages are needed for FLASH erase and programming operations, in-application programming
is also possible through other software-controlled communication paths. For a more detailed discussion of
in-circuit and in-application programming, refer to the HCS08 Family Reference Manual, Volume I,
Freescale Semiconductor document order number HCS08RMv1/D.
4.4.1 Features
Features of the FLASH memory include:
• FLASH Size
— MC9S08GB60/MC9S08GT60 — 61268 bytes (120 pages of 512 bytes each)
— MC9S08GB32/MC9S08GT32— 32768 bytes (64 pages of 512 bytes each)
— MC9S08GT16 — 16384 bytes (32 pages of 512 bytes each)
• Single power supply program and erase
• Command interface for fast program and erase operation
• Up to 100,000 program/erase cycles at typical voltage and temperature
• Flexible block protection
• Security feature for FLASH and RAM
• Auto power-down for low-frequency read accesses
4.4.2 Program and Erase Times
Before any program or erase command can be accepted, the FLASH clock divider register (FCDIV) must
be written to set the internal clock for the FLASH module to a frequency (f
200 kHz (see Table 4.6.1). This register can be written only once, so normally this write is done during
reset initialization. FCDIV cannot be written if the access error flag, FACCERR in FSTAT, is set. The user
must ensure that FACCERR is not set before writing to the FCDIV register. One period of the resulting
clock (1/f
) is used by the command processor to time program and erase pulses. An integer number
FCLK
of these timing pulses is used by the command processor to complete a program or erase command.
Table 4-5 shows program and erase times. The bus clock frequency and FCDIV determine the frequency
of FCLK (f
). The time for one cycle of FCLK is t
FCLK
of cycles of FCLK and as an absolute time for the case where t
FCLK
= 1/f
FCLK
. The times are shown as a number
FCLK
=5µs. Program and erase times
shown include overhead for the command state machine and enabling and disabling of program and erase
voltages.
Table 4-5. Program and Erase Times
Parameter Cycles of FCLK Time if FCLK = 200 kHz
Byte program 9 45 µs
Byte program (burst) 4
Page erase 4000 20 ms
Mass erase 20,000 100 ms
1
Excluding start/end overhead
) between 150 kHz and
FCLK
1
20 µs
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 47
Chapter 4 Memory
4.4.3 Program and Erase Command Execution
The steps for executing any of the commands are listed below. The FCDIV register must be initialized and
any error flags cleared before beginning command execution. The command execution steps are:
1. Write a data value to an address in the FLASH array. The address and data information from this
write is latched into the FLASH interface. This write is a required first step in any command
sequence. For erase and blank check commands, the value of the data is not important. For page
erase commands, the address may be any address in the 512-byte page of FLASH to be erased. For
mass erase and blank check commands, the address can be any address in the FLASH memory.
Whole pages of 512 bytes are the smallest blocks of FLASH that may be erased. In the 60K
version, there are two instances where the size of a block that is accessible to the user is less than
512 bytes: the first page following RAM, and the first page following the high page registers. These
pages are overlapped by the RAM and high page registers, respectively.
NOTE
Do not program any byte in the FLASH more than once after a successful
erase operation. Reprogramming bits in a byte which is already
programmed is not allowed without first erasing the page in which the byte
resides or mass erasing the entire FLASH memory. Programming without
first erasing may disturb data stored in the FLASH.
2. Write the command code for the desired command to FCMD. The five valid commands are blank
check ($05), byte program ($20), burst program ($25), page erase ($40), and mass erase ($41).
The command code is latched into the command buffer.
3. Write a 1 to the FCBEF bit in FSTAT to clear FCBEF and launch the command (including its
address and data information).
A partial command sequence can be aborted manually by writing a 0 to FCBEF any time after the write to
the memory array and before writing the 1 that clears FCBEF and launches the complete command.
Aborting a command in this way sets the FACCERR access error flag which must be cleared before
starting a new command.
A strictly monitored procedure must be adhered to, or the command will not be accepted. This minimizes
the possibility of any unintended change to the FLASH memory contents. The command complete flag
(FCCF) indicates when a command is complete. The command sequence must be completed by clearing
FCBEF to launch the command. Figure 4-2 is a flowchart for executing all of the commands except for
burst programming. The FCDIV register must be initialized before using any FLASH commands. This
must be done only once following a reset.
MC9S08GB/GT Data Sheet, Rev. 2.3
48 Freescale Semiconductor
START
FLASH
FACCERR ?
CLEAR ERROR
WRITE TO FCDIV
WRITE TO FLASH
TO BUFFER ADDRESS AND DATA
WRITE COMMAND TO FCMD
WRITE 1 TO FCBEF
TO LAUNCH COMMAND
AND CLEAR FCBEF
FPVIO OR
FACCERR ?
NO
0
FCCF ?
1
DONE
0
(1)
(2)
YES
(1)
Only required once
after reset.
(2)
Wait at least four bus cycles before
checking FCBEF or FCCF.
ERROR EXIT
Figure 4-2. FLASH Program and Erase Flowchart
4.4.4 Burst Program Execution
The burst program command is used to program sequential bytes of data in less time than would be
required using the standard program command. This is possible because the high voltage to the FLASH
array does not need to be disabled between program operations. Ordinarily, when a program or erase
command is issued, an internal charge pump associated with the FLASH memory must be enabled to
supply high voltage to the array. Upon completion of the command, the charge pump is turned off. When
a burst program command is issued, the charge pump is enabled and then remains enabled after completion
of the burst program operation if the following two conditions are met:
1. The next burst program command has been queued before the current program operation has
completed.
2. The next sequential address selects a byte on the same physical row as the current byte being
programmed. A row of FLASH memory consists of 64 bytes. A byte within a row is selected by
addresses A5 through A0. A new row begins when addresses A5 through A0 are all zero.
The first byte of a series of sequential bytes being programmed in burst mode will take the same amount
of time to program as a byte programmed in standard mode. Subsequent bytes will program in the burst
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 49
Chapter 4 Memory
program time provided that the conditions above are met. In the case the next sequential address is the
beginning of a new row, the program time for that byte will be the standard time instead of the burst time.
This is because the high voltage to the array must be disabled and then enabled again. If a new burst
command has not been queued before the current command completes, then the charge pump will be
disabled and high voltage removed from the array.
START
FACCERR ?
CLEAR ERROR
WRITE TO FCDIV
FCBEF ?
WRITE TO FLASH
TO BUFFER ADDRESS AND DATA
WRITE COMMAND TO FCMD
WRITE 1 TO FCBEF
TO LAUNCH COMMAND
AND CLEAR FCBEF
FPVIO OR
FACCERR ?
YES
NEW BURST COMMAND ?
NO
NO
0
1
(1)
1
(2)
(1)
Only required once
after reset.
0
(2)
Wait at least four bus cycles before
checking FCBEF or FCCF.
YES
ERROR EXIT
0
FCCF ?
1
DONE
Figure 4-3. FLASH Burst Program Flowchart
4.4.5 Access Errors
An access error occurs whenever the command execution protocol is violated.
• Any of the following specific actions will cause the access error flag (FACCERR) in FSTAT to be
set. FACCERR must be cleared by writing a 1 to FACCERR in FSTAT before any command can
be processed.
MC9S08GB/GT Data Sheet, Rev. 2.3
50 Freescale Semiconductor
FLASH
• Writing to a FLASH address before the internal FLASH clock frequency has been set by writing
to the FCDIV register
• Writing to a FLASH address while FCBEF is not set (A new command cannot be started until the
command buffer is empty.)
• Writing a second time to a FLASH address before launching the previous command (There is only
one write to FLASH for every command.)
• Writing a second time to FCMD before launching the previous command (There is only one write
to FCMD for every command.)
• Writing to any FLASH control register other than FCMD after writing to a FLASH address
• Writing any command code other than the five allowed codes ($05, $20, $25, $40, or $41) to
FCMD
• Accessing (read or write) any FLASH control register other than the write to FSTAT (to clear
FCBEF and launch the command) after writing the command to FCMD
• The MCU enters stop mode while a program or erase command is in progress (The command is
aborted.)
• Writing the byte program, burst program, or page erase command code ($20, $25, or $40) with a
background debug command while the MCU is secured (The background debug controller can
only do blank check and mass erase commands when the MCU is secure.)
• Writing 0 to FCBEF to cancel a partial command
4.4.6 FLASH Block Protection
Block protection prevents program or erase changes for FLASH memory locations in a designated address
range. Mass erase is disabled when any block of FLASH is protected. The MC9S08GB/GT allows a block
of memory at the end of FLASH, and/or the entire FLASH memory to be block protected. A disable
control bit and a 3-bit control field, allows the user to set the size of this block. A separate control bit allows
block protection of the entire FLASH memory array. All seven of these control bits are located in the
FPROT register (see Section 4.6.4, “FLASH Protection Register (FPROT and NVPROT)”).
At reset, the high-page register (FPROT) is loaded with the contents of the NVPROT location which is in
the nonvolatile register block of the FLASH memory. The value in FPROT cannot be changed directly
from application software so a runaway program cannot alter the block protection settings. If the last 512
bytes of FLASH which includes the NVPROT register is protected, the application program cannot alter
the block protection settings (intentionally or unintentionally). The FPROT control bits can be written by
background debug commands to allow a way to erase a protected FLASH memory.
One use for block protection is to block protect an area of FLASH memory for a bootloader program. This
bootloader program then can be used to erase the rest of the FLASH memory and reprogram it. Because
the bootloader is protected, it remains intact even if MCU power is lost in the middle of an erase and
reprogram operation.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 51
Chapter 4 Memory
4.4.7 Vector Redirection
Whenever any block protection is enabled, the reset and interrupt vectors will be protected. Vector
redirection allows users to modify interrupt vector information without unprotecting bootloader and reset
vector space. Vector redirection is enabled by programming the FNORED bit in the NVOPT register
located at address $FFBF to zero. For redirection to occur, at least some portion but not all of the FLASH
memory must be block protected by programming the NVPROT register located at address $FFBD. All of
the interrupt vectors (memory locations $FFC0–$FFFD) are redirected, while the reset vector
($FFFE:FFFF) is not. When more than 32K of memory is protected, vector redirection must not be
enabled.
For example, if 512 bytes of FLASH are protected, the protected address region is from $FE00 through
$FFFF. The interrupt vectors ($FFC0–$FFFD) are redirected to the locations $FDC0–$FDFD. Now, if an
SPI interrupt is taken for instance, the values in the locations $FDE0:FDE1 are used for the vector instead
of the values in the locations $FFE0:FFE1. This allows the user to reprogram the unprotected portion of
the FLASH with new program code including new interrupt vector values while leaving the protected area,
which includes the default vector locations, unchanged.
4.5 Security
The MC9S08GB/GT includes circuitry to prevent unauthorized access to the contents of FLASH and
RAM memory. When security is engaged, FLASH and RAM are considered secure resources. Direct-page
registers, high-page registers, and the background debug controller are considered unsecured resources.
Programs executing within secure memory have normal access to any MCU memory locations and
resources. Attempts to access a secure memory location with a program executing from an unsecured
memory space or through the background debug interface are blocked (writes are ignored and reads return
all 0s).
Security is engaged or disengaged based on the state of two nonvolatile register bits (SEC01:SEC00) in
the FOPT register. During reset, the contents of the nonvolatile location NVOPT are copied from FLASH
into the working FOPT register in high-page register space. A user engages security by programming the
NVOPT location which can be done at the same time the FLASH memory is programmed. The 1:0 state
disengages security while the other three combinations engage security. Notice the erased state (1:1)
makes the MCU secure. During development, whenever the FLASH is erased, it is good practice to
immediately program the SEC00 bit to 0 in NVOPT so SEC01:SEC00 = 1:0. This would allow the MCU
to remain unsecured after a subsequent reset.
The on-chip debug module cannot be enabled while the MCU is secure. The separate background debug
controller can still be used for background memory access commands, but the MCU cannot enter active
background mode except by holding BKGD/MS low at the rising edge of reset.
A user can choose to allow or disallow a security unlocking mechanism through an 8-byte backdoor
security key. If the nonvolatile KEYEN bit in NVOPT/FOPT is 0, the backdoor key is disabled and there
MC9S08GB/GT Data Sheet, Rev. 2.3
52 Freescale Semiconductor
FLASH Registers and Control Bits
is no way to disengage security without completely erasing all FLASH locations. If KEYEN is 1, a secure
user program can temporarily disengage security by:
1. Writing 1 to KEYACC in the FCNFG register. This makes the FLASH module interpret writes to
the backdoor comparison key locations (NVBACKKEY through NVBACKKEY+7) as values to
be compared against the key rather than as the first step in a FLASH program or erase command.
2. Writing the user-entered key values to the NVBACKKEY through NVBACKKEY+7 locations.
These writes must be done in order, starting with the value for NVBACKKEY and ending with
NVBACKKEY+7. STHX should not be used for these writes because these writes cannot be done
on adjacent bus cycles. User software normally would get the key codes from outside the MCU
system through a communication interface such as a serial I/O.
3. Writing 0 to KEYACC in the FCNFG register. If the 8-byte key that was just written matches the
key stored in the FLASH locations, SEC01:SEC00 are automatically changed to 1:0 and security
will be disengaged until the next reset.
The security key can be written only from RAM, so it cannot be entered through background commands
without the cooperation of a secure user program. The FLASH memory cannot be accessed by read
operations while KEYACC is set.
The backdoor comparison key (NVBACKKEY through NVBACKKEY+7) is located in FLASH memory
locations in the nonvolatile register space so users can program these locations just as they would program
any other FLASH memory location. The nonvolatile registers are in the same 512-byte block of FLASH
as the reset and interrupt vectors, so block protecting that space also block protects the backdoor
comparison key. Block protects cannot be changed from user application programs, so if the vector space
is block protected, the backdoor security key mechanism cannot permanently change the block protect,
security settings, or the backdoor key.
Security can always be disengaged through the background debug interface by performing these steps:
1. Disable any block protections by writing FPROT. FPROT can be written only with background
debug commands, not from application software.
2. Mass erase FLASH, if necessary.
3. Blank check FLASH. Provided FLASH is completely erased, security is disengaged until the next
reset.
To avoid returning to secure mode after the next reset, program NVOPT so SEC01:SEC00 = 1:0.
4.6 FLASH Registers and Control Bits
The FLASH module has nine 8-bit registers in the high-page register space, three locations in the
nonvolatile register space in FLASH memory that are copied into three corresponding high-page control
registers at reset. There is also an 8-byte comparison key in FLASH memory. Refer to Table 4-3 and
Table 4-4 for the absolute address assignments for all FLASH registers. This section refers to registers and
control bits only by their names. A Freescale-provided equate or header file normally is used to translate
these names into the appropriate absolute addresses.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 53
Chapter 4 Memory
4.6.1 FLASH Clock Divider Register (FCDIV)
Bit 7 of this register is a read-only status flag. Bits 6 through 0 may be read at any time but can be written
only one time. Before any erase or programming operations are possible, write to this register to set the
frequency of the clock for the nonvolatile memory system within acceptable limits.
Bit 7 6 54321Bit 0
Read: DIVLD
PRDIV8 DIV5 DIV4 DIV3 DIV2 DIV1 DIV0
Write:
Reset: 0 0 000000
= Unimplemented or Reserved
Figure 4-4. FLASH Clock Divider Register (FCDIV)
DIVLD — Divisor Loaded Status Flag
When set, this read-only status flag indicates that the FCDIV register has been written since reset.
Reset clears this bit and the first write to this register causes this bit to become set regardless of the
data written.
1 = FCDIV has been written since reset; erase and program operations enabled for FLASH.
0 = FCDIV has not been written since reset; erase and program operations disabled for FLASH.
PRDIV8 — Prescale (Divide) FLASH Clock by 8
1 = Clock input to the FLASH clock divider is the bus rate clock divided by 8.
0 = Clock input to the FLASH clock divider is the bus rate clock.
DIV5:DIV0 — Divisor for FLASH Clock Divider
The FLASH clock divider divides the bus rate clock (or the bus rate clock divided by 8 if PRDIV8 = 1)
by the value in the 6-bit DIV5:DIV0 field plus one. The resulting frequency of the internal FLASH
clock must fall within the range of 200 kHz to 150 kHz for proper FLASH operations. Program/erase
timing pulses are one cycle of this internal FLASH clock, which corresponds to a range of 5 µs to
6.7 µs. The automated programming logic uses an integer number of these pulses to complete an erase
or program operation.
if PRDIV8 = 0 — f
if PRDIV8 = 1 — f
FCLK
FCLK
= f
= f
Bus
÷ ([DIV5:DIV0] + 1) Eqn. 4-1
Bus
÷ (8 × ([DIV5:DIV0] + 1)) Eqn. 4-2
Table 4-6 shows the appropriate values for PRDIV8 and DIV5:DIV0 for selected bus frequencies.
MC9S08GB/GT Data Sheet, Rev. 2.3
54 Freescale Semiconductor
Table 4-6. FLASH Clock Divider Settings
FLASH Registers and Control Bits
f
Bus
20 MHz 1 12 192.3 kHz 5.2 µs
10 MHz 0 49 200 kHz 5 µs
8 MHz 0 39 200 kHz 5 µs
4 MHz 0 19 200 kHz 5 µs
2 MHz 0 9 200 kHz 5 µs
1 MHz 0 4 200 kHz 5 µs
200 kHz 0 0 200 kHz 5 µs
150 kHz 0 0 150 kHz 6.7 µs
PRDIV8
(Binary)
DIV5:DIV0
(Decimal)
f
FCLK
Program/Erase Timing Pulse
(5 µs Min, 6.7 µs Max)
4.6.2 FLASH Options Register (FOPT and NVOPT)
During reset, the contents of the nonvolatile location NVOPT are copied from FLASH into FOPT. Bits 5
through 2 are not used and always read 0. This register may be read at any time, but writes have no meaning
or effect. To change the value in this register, erase and reprogram the NVOPT location in FLASH memory
as usual and then issue a new MCU reset.
Bit 7 6 54321Bit 0
Read: KEYEN FNORED 0000SEC01 SEC00
Write:
Reset: This register is loaded from nonvolatile location NVOPT during reset.
= Unimplemented or Reserved
Figure 4-5. FLASH Options Register (FOPT)
KEYEN — Backdoor Key Mechanism Enable
When this bit is 0, the backdoor key mechanism cannot be used to disengage security. The backdoor
key mechanism is accessible only from user (secured) firmware. BDM commands cannot be used to
write key comparison values that would unlock the backdoor key. For more detailed information about
the backdoor key mechanism, refer to Section 4.5, “Security.”
1 = If user firmware writes an 8-byte value that matches the nonvolatile backdoor key
(NVBACKKEY through NVBACKKEY+7, in that order), security is temporarily disengaged
until the next MCU reset.
0 = No backdoor key access allowed.
FNORED — Vector Redirection Disable
When this bit is 1, vector redirection is disabled.
1 = Vector redirection disabled.
0 = Vector redirection enabled.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 55
Chapter 4 Memory
SEC01:SEC00 — Security State Code
This 2-bit field determines the security state of the MCU as shown in Table 4-7. When the MCU is
secure, the contents of RAM and FLASH memory cannot be accessed by instructions from any
unsecured source including the background debug interface. For more detailed information about
security, refer to Section 4.5, “Security.”
Table 4-7. Security States
SEC01:SEC00 Description
0:0 secure
0:1 secure
1:0 unsecured
1:1 secure
SEC01:SEC00 changes to 1:0 after successful backdoor key entry or a successful blank check of FLASH.
4.6.3 FLASH Configuration Register (FCNFG)
Bits 7 through 5 may be read or written at any time. Bits 4 through 0 always read 0 and cannot be written.
Bit 7 6 54321Bit 0
Read: 0 0
KEYACC
Write:
Reset: 0 0 000000
= Unimplemented or Reserved
Figure 4-6. FLASH Configuration Register (FCNFG)
00000
KEYACC — Enable Writing of Access Key
This bit enables writing of the backdoor comparison key. For more detailed information about the
backdoor key mechanism, refer to Section 4.5, “Security.”
1 = Writes to NVBACKKEY ($FFB0–$FFB7) are interpreted as comparison key writes.
Reads of the FLASH return invalid data.
0 = Writes to $FFB0–$FFB7 are interpreted as the start of a FLASH programming or erase
command.
4.6.4 FLASH Protection Register (FPROT and NVPROT)
During reset, the contents of the nonvolatile location NVPROT is copied from FLASH into FPROT. Bits 0,
1, and 2 are not used and each always reads as 0. This register may be read at any time, but user program
writes have no meaning or effect. Background debug commands can write to FPROT.
MC9S08GB/GT Data Sheet, Rev. 2.3
56 Freescale Semiconductor
Bit 7 6 54321Bit 0
Read: FPOPEN FPDIS FPS2 FPS1 FPS0 000
Write:
1
(1)
(1) (1) (1)
Reset: This register is loaded from nonvolatile location NVPROT during reset.
= Unimplemented or Reserved
1
Background commands can be used to change the contents of these bits in FPROT.
Figure 4-7. FLASH Protection Register (FPROT)
FPOPEN — Open Unprotected FLASH for Program/Erase
1 = Any FLASH location, not otherwise block protected or secured, may be erased or programmed.
0 = Entire FLASH memory is block protected (no program or erase allowed).
FPDIS — FLASH Protection Disable
1 = No FLASH block is protected.
0 = FLASH block specified by FPS2:FPS0 is block protected (program and erase not allowed).
FPS2:FPS1:FPS0 — FLASH Protect Size Selects
FLASH Registers and Control Bits
When FPDIS = 0, this 3-bit field determines the size of a protected block of FLASH locations at the
high address end of the FLASH (see Table 4-8). Protected FLASH locations cannot be erased or
programmed.
Table 4-8. High Address Protected Block
FPS2:FPS1:FPS0 Protected Address Range Protected Block Size Redirected Vectors
0:0:0 $FE00–$FFFF 512 bytes
0:0:1 $FC00–$FFFF 1024 bytes $FBC0–$FBFD
0:1:0 $F800–$FFFF 2048 bytes $F7C0–$F7FD
0:1:1 $F000–$FFFF 4096 bytes $EFC0–$EFFD
1:0:0 $E000–$FFFF 8192 bytes $DFC0–$DFFD
1:0:1 $C000–$FFFF 16384 bytes
1:1:0 $8000–$FFFF 32768 bytes
1:1:1 $8000–$FFFF 32768 bytes
1
No redirection if FPOPEN = 0, or FNORED = 1.
2
Reset vector is not redirected.
3
32K and 60K devices only.
4
60K devices only.
$FDC0–$FDFD
$BFC0–$BFFD
$7FC0–$7FFD
$7FC0–$7FFD
1
2
3
4
4
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 57
Chapter 4 Memory
4.6.5 FLASH Status Register (FSTAT)
Bits 3, 1, and 0 always read 0 and writes have no meaning or effect. The remaining five bits are status bits
that can be read at any time. Writes to these bits have special meanings that are discussed in the bit
descriptions.
Bit 7 6 54321Bit 0
Read:
FCBEF
Write:
Reset: 1 1 000000
Figure 4-8. FLASH Status Register (FSTAT)
FCCF
FPVIOL FACCERR
= Unimplemented or Reserved
0 FBLANK 00
FCBEF — FLASH Command Buffer Empty Flag
The FCBEF bit is used to launch commands. It also indicates that the command buffer is empty so that
a new command sequence can be executed when performing burst programming. The FCBEF bit is
cleared by writing a 1 to it or when a burst program command is transferred to the array for
programming. Only burst program commands can be buffered.
1 = A new burst program command may be written to the command buffer.
0 = Command buffer is full (not ready for additional commands).
FCCF — FLASH Command Complete Flag
FCCF is set automatically when the command buffer is empty and no command is being processed.
FCCF is cleared automatically when a new command is started (by writing 1 to FCBEF to register a
command). Writing to FCCF has no meaning or effect.
1 = All commands complete
0 = Command in progress
FPVIOL — Protection Violation Flag
FPVIOL is set automatically when FCBEF is cleared to register a command that attempts to erase or
program a location in a protected block (the erroneous command is ignored). FPVIOL is cleared by
writing a 1 to FPVIOL.
1 = An attempt was made to erase or program a protected location.
0 = No protection violation.
FACCERR — Access Error Flag
FACCERR is set automatically when the proper command sequence is not followed exactly (the
erroneous command is ignored), if a program or erase operation is attempted before the FCDIV register
has been initialized, or if the MCU enters stop while a command was in progress. For a more detailed
discussion of the exact actions that are considered access errors, see Section 4.4.5, “Access Errors.”
FACCERR is cleared by writing a 1 to FACCERR. Writing a 0 to FACCERR has no meaning or effect.
1 = An access error has occurred.
0 = No access error has occurred.
MC9S08GB/GT Data Sheet, Rev. 2.3
58 Freescale Semiconductor
FLASH Registers and Control Bits
FBLANK — FLASH Verified as All Blank (Erased) Flag
FBLANK is set automatically at the conclusion of a blank check command if the entire FLASH array
was verified to be erased. FBLANK is cleared by clearing FCBEF to write a new valid command.
Writing to FBLANK has no meaning or effect.
1 = After a blank check command is completed and FCCF = 1, FBLANK = 1 indicates the FLASH
array is completely erased (all $FF).
0 = After a blank check command is completed and FCCF = 1, FBLANK = 0 indicates the FLASH
array is not completely erased.
4.6.6 FLASH Command Register (FCMD)
Only five command codes are recognized in normal user modes as shown in Table 4-9. Refer to
Section 4.4.3, “Program and Erase Command Execution” for a detailed discussion of FLASH
programming and erase operations.
Bit 7 6 54321Bit 0
Read: 0 0 000000
Write: FCMD7 FCMD6 FCMD5 FCMD4 FCMD3 FCMD2 FCMD1 FCMD0
Reset: 0 0 000000
= Unimplemented or Reserved
Figure 4-9. FLASH Command Register (FCMD)
Table 4-9. FLASH Commands
Command FCMD Equate File Label
Blank check $05 mBlank
Byte program $20 mByteProg
Byte program — burst mode $25 mBurstProg
Page erase (512 bytes/page) $40 mPageErase
Mass erase (all FLASH) $41 mMassErase
All other command codes are illegal and generate an access error.
It is not necessary to perform a blank check command after a mass erase operation. Only blank check is
required as part of the security unlocking mechanism.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 59
Chapter 4 Memory
MC9S08GB/GT Data Sheet, Rev. 2.3
60 Freescale Semiconductor
Chapter 5 Resets, Interrupts, and System Configuration
5.1 Introduction
This section discusses basic reset and interrupt mechanisms and the various sources of reset and interrupts
in the MC9S08GB/GT. Some interrupt sources from peripheral modules are discussed in greater detail
within other sections of this data manual. This section gathers basic information about all reset and
interrupt sources in one place for easy reference. A few reset and interrupt sources, including the computer
operating properly (COP) watchdog and real-time interrupt (RTI), are not part of on-chip peripheral
systems with their own sections but are part of the system control logic.
5.2 Features
Reset and interrupt features include:
• Multiple sources of reset for flexible system configuration and reliable operation:
— Power-on detection (POR)
— Low voltage detection (LVD) with enable
— External
— COP watchdog with enable and two timeout choices
— Illegal opcode
RESET pin with enable
— Serial command from a background debug host
• Reset status register (SRS) to indicate source of most recent reset
• Separate interrupt vectors for each module (reduces polling overhead) (see Table 5-1)
5.3 MCU Reset
Resetting the MCU provides a way to start processing from a known set of initial conditions. During reset,
most control and status registers are forced to initial values and the program counter is loaded from the
reset vector ($FFFE:$FFFF). On-chip peripheral modules are disabled and I/O pins are initially configured
as general-purpose high-impedance inputs with pullup devices disabled. The I bit in the condition code
register (CCR) is set to block maskable interrupts so the user program has a chance to initialize the stack
pointer (SP) and system control settings. SP is forced to $00FF at reset.
The MC9S08GB/GT has seven sources for reset:
• Power-on reset (POR)
• Low-voltage detect (LVD)
• Computer operating properly (COP) timer
• Illegal opcode detect
• Background debug forced reset
• The reset pin (
• Clock generator loss of lock and loss of clock reset
RESET)
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 61
Chapter 5 Resets, Interrupts, and System Configuration
Each of these sources, with the exception of the background debug forced reset, has an associated bit in
the system reset status register. Whenever the MCU enters reset, the internal clock generator (ICG) module
switches to self-clocked mode with the frequency of f
Self_reset
selected. The reset pin is driven low for 34
internal bus cycles where the internal bus frequency is half the ICG frequency. After the 34 cycles are
completed, the pin is released and will be pulled up by the internal pullup resistor, unless it is held low
externally. After the pin is released, it is sampled after another 38 cycles to determine whether the reset pin
is the cause of the MCU reset.
5.4 Computer Operating Properly (COP) Watchdog
The COP watchdog is intended to force a system reset when the application software fails to execute as
expected. To prevent a system reset from the COP timer (when it is enabled), application software must
reset the COP timer periodically. If the application program gets lost and fails to reset the COP before it
times out, a system reset is generated to force the system back to a known starting point. The COP
watchdog is enabled by the COPE bit in SOPT (see Section 5.8.4, “System Options Register (SOPT)” for
additional information). The COP timer is reset by writing any value to the address of SRS. This write does
not affect the data in the read-only SRS. Instead, the act of writing to this address is decoded and sends a
reset signal to the COP timer.
After any reset, the COP timer is enabled. This provides a reliable way to detect code that is not executing
as intended. If the COP watchdog is not used in an application, it can be disabled by clearing the COPE
bit in the write-once SOPT register. Also, the COPT bit can be used to choose one of two timeout periods
18
or 213cycles of the bus rate clock). Even if the application will use the reset default settings in COPE
(2
and COPT, the user should still write to write-once SOPT during reset initialization to lock in the settings.
That way, they cannot be changed accidentally if the application program gets lost.
The write to SRS that services (clears) the COP timer should not be placed in an interrupt service routine
(ISR) because the ISR could continue to be executed periodically even if the main application program
fails.
When the MCU is in active background mode, the COP timer is temporarily disabled.
5.5 Interrupts
Interrupts provide a way to save the current CPU status and registers, execute an interrupt service routine
(ISR), and then restore the CPU status so processing resumes where it left off before the interrupt. Other
than the software interrupt (SWI), which is a program instruction, interrupts are caused by hardware events
such as an edge on the IRQ pin or a timer-overflow event. The debug module can also generate an SWI
under certain circumstances.
If an event occurs in an enabled interrupt source, an associated read-only status flag will become set. The
CPU will not respond until and unless the local interrupt enable is set to 1 to enable the interrupt. The I bit
in the CCR is 0 to allow interrupts. The global interrupt mask (I bit) in the CCR is initially set after reset
which masks (prevents) all maskable interrupt sources. The user program initializes the stack pointer and
performs other system setup before clearing the I bit to allow the CPU to respond to interrupts.
MC9S08GB/GT Data Sheet, Rev. 2.3
62 Freescale Semiconductor
Interrupts
When the CPU receives a qualified interrupt request, it completes the current instruction before responding
to the interrupt. The interrupt sequence follows the same cycle-by-cycle sequence as the SWI instruction
and consists of:
• Saving the CPU registers on the stack
• Setting the I bit in the CCR to mask further interrupts
• Fetching the interrupt vector for the highest-priority interrupt that is currently pending
• Filling the instruction queue with the first three bytes of program information starting from the
address fetched from the interrupt vector locations
While the CPU is responding to the interrupt, the I bit is automatically set to avoid the possibility of another
interrupt interrupting the ISR itself (this is called nesting of interrupts). Normally, the I bit is restored to 0
when the CCR is restored from the value stacked on entry to the ISR. In rare cases, the I bit may be cleared
inside an ISR (after clearing the status flag that generated the interrupt) so that other interrupts can be
serviced without waiting for the first service routine to finish. This practice is not recommended for anyone
other than the most experienced programmers because it can lead to subtle program errors that are difficult
to debug.
The interrupt service routine ends with a return-from-interrupt (RTI) instruction which restores the CCR,
A, X, and PC registers to their pre-interrupt values by reading the previously saved information off the
stack.
NOTE
For compatibility with the M68HC08, the H register is not automatically
saved and restored. It is good programming practice to push H onto the stack
at the start of the interrupt service routine (ISR) and restore it just before the
RTI that is used to return from the ISR.
When two or more interrupts are pending when the I bit is cleared, the highest priority source is serviced
first (see Table 5-1).
5.5.1 Interrupt Stack Frame
Figure 5-1 shows the contents and organization of a stack frame. Before the interrupt, the stack pointer
(SP) points at the next available byte location on the stack. The current values of CPU registers are stored
on the stack starting with the low-order byte of the program counter (PCL) and ending with the CCR. After
stacking, the SP points at the next available location on the stack which is the address that is one less than
the address where the CCR was saved. The PC value that is stacked is the address of the instruction in the
main program that would have executed next if the interrupt had not occurred.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 63
Chapter 5 Resets, Interrupts, and System Configuration
UNSTACKING
ORDER
TOWARD LOWER ADDRESSES
5
4
3
2
1
STACKING
ORDER
70
1
2
3
4
5
CONDITION CODE REGISTER
ACCUMULATOR
INDEX REGISTER (LOW BYTE X)
PROGRAM COUNTER HIGH
PROGRAM COUNTER LOW
* High byte (H) of index register is not automatically stacked.
*
TOWARD HIGHER ADDRESSES
SP AFTER
INTERRUPT STACKING
SP BEFORE
THE INTERRUPT
Figure 5-1. Interrupt Stack Frame
When an RTI instruction is executed, these values are recovered from the stack in reverse order. As part of
the RTI sequence, the CPU fills the instruction pipeline by reading three bytes of program information,
starting from the PC address just recovered from the stack.
The status flag causing the interrupt must be acknowledged (cleared) before returning from the ISR.
Typically, the flag should be cleared at the beginning of the ISR so that if another interrupt is generated by
this same source, it will be registered so it can be serviced after completion of the current ISR.
5.5.2 External Interrupt Request (IRQ) Pin
External interrupts are managed by the IRQSC status and control register. When the IRQ function is
enabled, synchronous logic monitors the pin for edge-only or edge-and-level events. When the MCU is in
stop mode and system clocks are shut down, a separate asynchronous path is used so the IRQ (if enabled)
can wake the MCU.
5.5.2.1 Pin Configuration Options
The IRQ pin enable (IRQPE) control bit in the IRQSC register must be 1 for the IRQ pin to act as the
interrupt request (IRQ) input. When the pin is configured as an IRQ input, the user can choose the polarity
of edges or levels detected (IRQEDG), whether the pin detects edges-only or edges and levels (IRQMOD),
and whether an event causes an interrupt or only sets the IRQF flag (which can be polled by software).
When the IRQ pin is configured to detect rising edges, an optional pulldown resistor is available rather than
a pullup resistor. BIH and BIL instructions may be used to detect the level on the IRQ pin when the pin is
configured to act as the IRQ input.
MC9S08GB/GT Data Sheet, Rev. 2.3
64 Freescale Semiconductor
Interrupts
NOTE
The voltage measured on the pulled up IRQ pin may be as low as V
V. The internal gates connected to this pin are pulled all the way to V
DD
DD
– 0.7
. All
other pins with enabled pullup resistors will have an unloaded measurement
DD
.
of V
5.5.2.2 Edge and Level Sensitivity
The IRQMOD control bit re-configures the detection logic so it detects edge events and pin levels. In this
edge detection mode, the IRQF status flag becomes set when an edge is detected (when the IRQ pin
changes from the deasserted to the asserted level), but the flag is continuously set (and cannot be cleared)
as long as the IRQ pin remains at the asserted level.
5.5.3 Interrupt Vectors, Sources, and Local Masks
Table 5-1 provides a summary of all interrupt sources. Higher-priority sources are located toward the
bottom of the table. The high-order byte of the address for the interrupt service routine is located at the
first address in the vector address column, and the low-order byte of the address for the interrupt service
routine is located at the next higher address.
When an interrupt condition occurs, an associated flag bit becomes set. If the associated local interrupt
enable is 1, an interrupt request is sent to the CPU. Within the CPU, if the global interrupt mask (I bit in
the CCR) is 0, the CPU will finish the current instruction, stack the PCL, PCH, X, A, and CCR CPU
registers, set the I bit, and then fetch the interrupt vector for the highest priority pending interrupt.
Processing then continues in the interrupt service routine.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 65
Chapter 5 Resets, Interrupts, and System Configuration
Table 5-1. Vector Summary
Vector
Priority
Lower
Higher
Vector
Number
26
through
31
25 $FFCC/FFCD Vrti
24 $FFCE/FFCF Viic1 IIC IICIS IICIE IIC control
23 $FFD0/FFD1 Vatd1 ATD COCO AIEN
22 $FFD2/FFD3 Vkeyboard1 KBI KBF KBIE Keyboard pins
21 $FFD4/FFD5 Vsci2tx SCI2
20 $FFD6/FFD7 Vsci2rx SCI2
19 $FFD8/FFD9 Vsci2err SCI2
18 $FFDA/FFDB Vsci1tx SCI1
17 $FFDC/FFDD Vsci1rx SCI1
16 $FFDE/FFDF Vsci1err SCI1
15 $FFE0/FFE1 Vspi1 SPI
14 $FFE2/FFE3 Vtpm2ovf TPM2 TOF TOIE TPM2 overflow
13 $FFE4/FFE5 Vtpm2ch4 TPM2 CH4F CH4IE TPM2 channel 4
12 $FFE6/FFE7 Vtpm2ch3 TPM2 CH3F CH3IE TPM2 channel 3
11 $FFE8/FFE9 Vtpm2ch2 TPM2 CH2F CH2IE TPM2 channel 2
10 $FFEA/FFEB Vtpm2ch1 TPM2 CH1F CH1IE TPM2 channel 1
9 $FFEC/FFED Vtpm2ch0 TPM2 CH0F CH0IE TPM2 channel 0
8 $FFEE/FFEF Vtpm1ovf TPM1 TOF TOIE TPM1 overflow
7 $FFF0/FFF1 Vtpm1ch2 TPM1 CH2F CH2IE TPM1 channel 2
6 $FFF2/FFF3 Vtpm1ch1 TPM1 CH1F CH1IE TPM1 channel 1
5 $FFF4/FFF5 Vtpm1ch0 TPM1 CH0F CH0IE TPM1 channel 0
4 $FFF6/FFF7 Vicg ICG
3 $FFF8/FFF9 Vlvd
2 $FFFA/FFFB Virq IRQ IRQF IRQIE IRQ pin
1 $FFFC/FFFD Vswi Core
0 $FFFE/FFFF Vreset
Address
(High/Low)
$FFC0/FFC1
through
$FFCA/FFCB
Vector Name Module Source Enable Description
Unused Vector Space
(available for user program)
System
control
System
control
System
control
RTIF RTIE Real-time interrupt
AD conversion
complete
TDRE
TC
IDLE
RDRF
OR
NF
FE
PF
TDRE
TC
IDLE
RDRF
OR
NF
FE
PF
SPIF
MODF
SPTEF
ICGIF
(LOLS/LOCS)
LVDF LVDIE Low-voltage detect
SWI
Instruction
COP
LV D
RESET pin
Illegal opcode
TIE
TCIE
ILIE
RIE
ORIE
NFIE
FEIE
PFIE
TIE
TCIE
ILIE
RIE
ORIE
NFIE
FEIE
PFIE
SPIE
SPIE
SPTIE
LOLRE/LOCRE ICG
— Software interrupt
COPE
LVDRE
—
—
SCI2 transmit
SCI2 receive
SCI2 error
SCI1 transmit
SCI1 receive
SCI1 error
SPI
Watchdog timer
Low-voltage detect
External pin
Illegal opcode
MC9S08GB/GT Data Sheet, Rev. 2.3
66 Freescale Semiconductor
Low-Voltage Detect (LVD) System
5.6 Low-Voltage Detect (LVD) System
The MC9S08GB/GT includes a system to protect against low voltage conditions to protect memory
contents and control MCU system states during supply voltage variations. The system comprises a
power-on reset (POR) circuit and an LVD circuit with a user selectable trip voltage, either high (V
or low (V
). The LVD circuit is enabled when LVDE in SPMSC1 is high and the trip voltage is selected
LVDL
by LVDV in SPMSC2. The LVD is disabled upon entering any of the stop modes unless the LVDSE bit is
set. If LVDSE and LVDE are both set, then the MCU cannot enter stop1 or stop2, and the current
consumption in stop3 with the LVD enabled will be greater.
5.6.1 Power-On Reset Operation
LVDH
)
When power is initially applied to the MCU, or when the supply voltage drops below the V
POR
level, the
POR circuit will cause a reset condition. As the supply voltage rises, the LVD circuit will hold the chip in
reset until the supply has risen above the V
level. Both the POR bit and the LVD bit in SRS are set
LVDL
following a POR.
5.6.2 LVD Reset Operation
The LVD can be configured to generate a reset upon detection of a low voltage condition by setting
LVDRE to 1. After an LVD reset has occurred, the LVD system will hold the MCU in reset until the supply
voltage has risen above the level determined by LVDV. The LVD bit in the SRS register is set following
either an LVD reset or POR.
5.6.3 LVD Interrupt Operation
When a low voltage condition is detected and the LVD circuit is configured for interrupt operation (LVDE
set, LVDIE set, and LVDRE clear), then LVDF will be set and an LVD interrupt will occur.
5.6.4 Low-Voltage Warning (LVW)
The LVD system has a low voltage warning flag to indicate to the user that the supply voltage is
approaching, but is still above, the LVD voltage. The LVW does not have an interrupt associated with it.
There are two user selectable trip voltages for the LVW, one high (V
voltage is selected by LVWV in SPMSC2.
) and one low (V
LVWH
LVWL
). The trip
5.7 Real-Time Interrupt (RTI)
The real-time interrupt function can be used to generate periodic interrupts based on a multiple of the
source clock's period. The RTI has two source clock choices, the external clock input (ICGERCLK) to the
ICG or the RTI's own internal clock. The RTI can be used in run, wait, stop2 and stop3 modes. It is not
available in stop1 mode.
In run and wait modes, only the external clock can be used as the RTI's clock source. In stop2 mode, only
the internal RTI clock can be used. In stop3, either the external clock or internal RTI clock can be used.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 67
Chapter 5 Resets, Interrupts, and System Configuration
When using the external oscillator in stop3 mode, it must be enabled in stop (OSCSTEN = 1) and
configured for low bandwidth operation (RANGE = 0).
The SRTISC register includes a read-only status flag, a write-only acknowledge bit, and a 3-bit control
value (RTIS2:RTIS1:RTIS0) used to select one of seven RTI periods. The RTI has a local interrupt enable,
RTIE, to allow masking of the real-time interrupt. The module can be disabled by writing 0:0:0 to
RTIS2:RTIS1:RTIS0 in which case the clock source input is disabled and no interrupts will be generated.
See Section 5.8.6, “System Real-Time Interrupt Status and Control Register (SRTISC),” for detailed
information about this register.
5.8 Reset, Interrupt, and System Control Registers and Control Bits
One 8-bit register in the direct page register space and eight 8-bit registers in the high-page register space
are related to reset and interrupt systems.
Refer to the direct-page register summary in Chapter 4, “Memory,” of this data sheet for the absolute
address assignments for all registers. This section refers to registers and control bits only by their names.
A Freescale-provided equate or header file is used to translate these names into the appropriate absolute
addresses.
Some control bits in the SOPT and SPMSC2 registers are related to modes of operation. Although brief
descriptions of these bits are provided here, the related functions are discussed in greater detail in
Chapter 3, “Modes of Operation.”
5.8.1 Interrupt Pin Request Status and Control Register (IRQSC)
This direct page register includes two unimplemented bits which always read 0, four read/write bits, one
read-only status bit, and one write-only bit. These bits are used to configure the IRQ function, report status,
and acknowledge IRQ events.
Bit 7 654321Bit 0
Read: 0 0
IRQEDG IRQPE
Write: IRQACK
Reset: 00000000
= Unimplemented or Reserved
Figure 5-2. Interrupt Request Status and Control Register (IRQSC)
IRQEDG — Interrupt Request (IRQ) Edge Select
This read/write control bit is used to select the polarity of edges or levels on the IRQ pin that cause
IRQF to be set. The IRQMOD control bit determines whether the IRQ pin is sensitive to both edges
and levels or only edges. When the IRQ pin is enabled as the IRQ input and is configured to detect
rising edges, the optional pullup resistor is re-configured as an optional pulldown resistor.
1 = IRQ is rising edge or rising edge/high-level sensitive.
0 = IRQ is falling edge or falling edge/low-level sensitive.
IRQF 0
IRQIE IRQMOD
MC9S08GB/GT Data Sheet, Rev. 2.3
68 Freescale Semiconductor
Reset, Interrupt, and System Control Registers and Control Bits
IRQPE — IRQ Pin Enable
This read/write control bit enables the IRQ pin function. When this bit is set, the IRQ pin can be used
as an interrupt request. Also, when this bit is set, either an internal pull-up or an internal pull-down
resistor is enabled depending on the state of the IRQMOD bit.
1 = IRQ pin function is enabled.
0 = IRQ pin function is disabled.
IRQF — IRQ Flag
This read-only status bit indicates when an interrupt request event has occurred.
1 = IRQ event detected.
0 = No IRQ request.
IRQACK — IRQ Acknowledge
This write-only bit is used to acknowledge interrupt request events (write 1 to clear IRQF). Writing 0
has no meaning or effect. Reads always return 0. If edge-and-level detection is selected
(IRQMOD = 1), IRQF cannot be cleared while the IRQ pin remains at its asserted level.
IRQIE — IRQ Interrupt Enable
This read/write control bit determines whether IRQ events generate a hardware interrupt request.
1 = Hardware interrupt requested whenever IRQF = 1.
0 = Hardware interrupt requests from IRQF disabled (use polling).
IRQMOD — IRQ Detection Mode
This read/write control bit selects either edge-only detection or edge-and-level detection. The
IRQEDG control bit determines the polarity of edges and levels that are detected as interrupt request
events. See Section 5.5.2.2, “Edge and Level Sensitivity” for more details.
1 = IRQ event on falling edges and low levels or on rising edges and high levels.
0 = IRQ event on falling edges or rising edges only.
5.8.2 System Reset Status Register (SRS)
This register includes six read-only status flags to indicate the source of the most recent reset. When a
debug host forces reset by writing 1 to BDFR in the SBDFR register, none of the status bits in SRS will be
set. Writing any value to this register address clears the COP watchdog timer without affecting the contents
of this register. The reset state of these bits depends on what caused the MCU to reset.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 69
Chapter 5 Resets, Interrupts, and System Configuration
Bit 7 6 54321Bit 0
Read: POR PIN COP ILOP 0 ICG LVD 0
Write:
Power-on reset: 1 0 000010
Low-voltage reset: U 0 000010
Any other reset: 0
U = Unaffected by reset
1
Any of these reset sources that are active at the time of reset will cause the corresponding bit(s) to be set; bits
corresponding to sources that are not active at the time of reset will be cleared.
Writing any value to SIMRS address clears COP watchdog timer.
1
Figure 5-3. System Reset Status (SRS)
(1) (1)
0
(1)
00
POR — Power-On Reset
Reset was caused by the power-on detection logic. Because the internal supply voltage was ramping
up at the time, the low-voltage reset (LVD) status bit is also set to indicate that the reset occurred while
the internal supply was below the LVD threshold.
1 = POR caused reset.
0 = Reset not caused by POR.
PIN — External Reset Pin
Reset was caused by an active-low level on the external reset pin.
1 = Reset came from external reset pin.
0 = Reset not caused by external reset pin.
COP — Computer Operating Properly (COP) Watchdog
Reset was caused by the COP watchdog timer timing out. This reset source may be blocked by
COPE = 0.
1 = Reset caused by COP timeout.
0 = Reset not caused by COP timeout.
ILOP — Illegal Opcode
Reset was caused by an attempt to execute an unimplemented or illegal opcode. The STOP instruction
is considered illegal if stop is disabled by STOPE = 0 in the SOPT register. The BGND instruction is
considered illegal if active background mode is disabled by ENBDM = 0 in the BDCSC register.
1 = Reset caused by an illegal opcode.
0 = Reset not caused by an illegal opcode.
ICG — Internal Clock Generation Module Reset
Reset was caused by an ICG module reset.
1 = Reset caused by ICG module.
0 = Reset not caused by ICG module.
MC9S08GB/GT Data Sheet, Rev. 2.3
70 Freescale Semiconductor
Reset, Interrupt, and System Control Registers and Control Bits
LVD — Low Voltage Detect
If the LVD reset is enabled (LVDE = LVDRE = 1) and the supply drops below the LVD trip voltage,
an LVD reset occurs. The LVD function is disabled when the MCU enters stop. To maintain LVD
operation in stop, the LVDSE bit must be set.
1 = Reset caused by LVD trip or POR.
0 = Reset not caused by LVD trip or POR.
5.8.3 System Background Debug Force Reset Register (SBDFR)
This register contains a single write-only control bit. A serial background command such as
WRITE_BYTE must be used to write to SBDFR. Attempts to write this register from a user program are
ignored. Reads always return $00.
Bit 7 654321Bit 0
Read: 00000000
Write: BDFR
Reset: 00000000
= Unimplemented or Reserved
1
BDFR is writable only through serial background debug commands, not from user programs.
1
Figure 5-4. System Background Debug Force Reset Register (SBDFR)
BDFR — Background Debug Force Reset
A serial background mode command such as WRITE_BYTE allows an external debug host to force a
target system reset. Writing 1 to this bit forces an MCU reset. This bit cannot be written from a user
program.
5.8.4 System Options Register (SOPT)
This register may be read at any time. Bits 3 and 2 are unimplemented and always read 0. This is a
write-once register so only the first write after reset is honored. Any subsequent attempt to write to SOPT
(intentionally or unintentionally) is ignored to avoid accidental changes to these sensitive settings. SOPT
should be written during the user’s reset initialization program to set the desired controls even if the desired
settings are the same as the reset settings.
Bit 7 654321Bit 0
Read:
COPE COPT STOPE
Write:
Reset: 11010011
= Unimplemented or Reserved
Figure 5-5. System Options Register (SOPT)
00
BKGDPE
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 71
Chapter 5 Resets, Interrupts, and System Configuration
COPE — COP Watchdog Enable
This write-once bit defaults to 1 after reset.
1 = COP watchdog timer enabled (force reset on timeout).
0 = COP watchdog timer disabled.
COPT — COP Watchdog Timeout
This write-once bit defaults to 1 after reset.
18
1 = Long timeout period selected (2
0 = Short timeout period selected (2
cycles of BUSCLK).
13
cycles of BUSCLK).
STOPE — Stop Mode Enable
This write-once bit defaults to 0 after reset, which disables stop mode. If stop mode is disabled and a
user program attempts to execute a STOP instruction, an illegal opcode reset is forced.
1 = Stop mode enabled.
0 = Stop mode disabled.
BKGDPE — Background Debug Mode Pin Enable
The BKGDPE bit enables the PTG0/BKGD/MS pin to function as BKGD/MS. When the bit is clear,
the pin will function as PTG0, which is an output-only general-purpose I/O. This pin always defaults
to BKGD/MS function after any reset.
1 = BKGD pin enabled.
0 = BKGD pin disabled.
5.8.5 System Device Identification Register (SDIDH, SDIDL)
This read-only register is included so host development systems can identify the HCS08 derivative and
revision number. This allows the development software to recognize where specific memory blocks,
registers, and control bits are located in a target MCU.
Bit 7 6 5 4321Bit 0
Read: REV3 REV2 REV1 REV0 ID11 ID10 ID9 ID8
Reset: 0
Read: ID7 ID6 ID5 ID4 ID3 ID2 ID1 ID0
Reset: 0 0 0 00010
1
The revision number that is hard coded into these bits reflects the current silicon revision level.
Figure 5-6. System Device Identification Register (SDIDH, SDIDL)
1
REV[3:0] — Revision Number
The high-order 4 bits of address $1806 are hard coded to reflect the current mask set revision number
(0–F).
(1)
0
= Unimplemented or Reserved
(1)
0
(1)
0
0000
MC9S08GB/GT Data Sheet, Rev. 2.3
72 Freescale Semiconductor
Reset, Interrupt, and System Control Registers and Control Bits
ID[11:0] — Part Identification Number
Each derivative in the HCS08 Family has a unique identification number. The MC9S08GB/GT is hard
coded to the value $002.
5.8.6 System Real-Time Interrupt Status and Control Register (SRTISC)
This register contains one read-only status flag, one write-only acknowledge bit, three read/write delay
selects, and three unimplemented bits, which always read 0.
Bit 7 6 5 4321Bit 0
Read: RTIF 0
RTICLKS RTIE
Write: RTIACK
Reset: 0 0 0 00000
= Unimplemented or Reserved
Figure 5-7. System RTI Status and Control Register (SRTISC)
0
RTIS2 RTIS1 RTIS0
RTIF — Real-Time Interrupt Flag
This read-only status bit indicates the periodic wakeup timer has timed out.
1 = Periodic wakeup timer timed out.
0 = Periodic wakeup timer not timed out.
RTIACK — Real-Time Interrupt Acknowledge
This write-only bit is used to acknowledge real-time interrupt request (write 1 to clear RTIF). Writing
0 has no meaning or effect. Reads always return 0.
RTICLKS — Real-Time Interrupt Clock Select
This read/write bit selects the clock source for the real-time interrupt.
1 = Real-time interrupt request clock source is external clock.
0 = Real-time interrupt request clock source is internal oscillator.
RTIE — Real-Time Interrupt Enable
This read-write bit enables real-time interrupts.
1 = Real-time interrupts enabled.
0 = Real-time interrupts disabled.
RTIS2:RTIS1:RTIS0 — Real-Time Interrupt Period Selects
These read/write bits select the wakeup period for the RTI. The clock source for the real-time interrupt
is its own clock source, which oscillates with a period of approximately 1/f
, and it is independent of
ext
other MCU clock sources. Using an external clock source, the delays will be crystal frequency divided
by value in RTIS2:RTIS1:RTIS0.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 73
Chapter 5 Resets, Interrupts, and System Configuration
Table 5-2. Real-Time Interrupt Period
RTIS2:RTIS1:RTIS0
0:0:0 Disable periodic wakeup timer Disable periodic wakeup timer
0:0:1 8 ms
0:1:0 32 ms
0:1:1 64 ms
1:0:0 128 ms
1:0:1 256 ms
1:1:0 512 ms
1:1:1 1.024 s
1
See Table A-10 t
2
t
is based on the external clock source, resonator, or crystal selected by the ICG configuration. See Table A-9 for details.
ext
in Appendix A, “Electrical Characteristics” for the tolerance on these values.
RTI
Internal Clock Source
(t
= 1 ms, Nominal)
RTI
1
External Clock Source
Period = t
t
ext
t
ex
t
ex
t
ex
t
ext
t
ext
t
ex
ext
x 256
x 1024
x 2048
x 4096
x 8192
x 16384
x 32768
2
5.8.7 System Power Management Status and Control 1 Register (SPMSC1)
Bit 7 6 54321Bit 0
Read: LVDF 0
Write: LVDACK
LVDIE LVDRE
1
LVDSE
(1)
LVDE
(1)
00
Reset: 0 0 011100
= Unimplemented or Reserved
1
This bit can be written only one time after reset. Additional writes are ignored.
Figure 5-8. System Power Management Status and Control 1 Register (SPMSC1)
LVDF — Low-Voltage Detect Flag
Provided LVDE = 1, this read-only status bit indicates a low-voltage detect event.
LVDACK — Low-Voltage Detect Acknowledge
This write-only bit is used to acknowledge low voltage detection errors (write 1 to clear LVDF). Reads
always return 0.
LVDIE — Low-Voltage Detect Interrupt Enable
This read/write bit enables hardware interrupt requests for LVDF.
1 = Request a hardware interrupt when LVDF = 1.
0 = Hardware interrupt disabled (use polling).
MC9S08GB/GT Data Sheet, Rev. 2.3
74 Freescale Semiconductor
Reset, Interrupt, and System Control Registers and Control Bits
LVDRE — Low-Voltage Detect Reset Enable
This read/write bit enables LVDF events to generate a hardware reset (provided LVDE = 1).
1 = Force an MCU reset when LVDF = 1.
0 = LVDF does not generate hardware resets.
LVDSE — Low-Voltage Detect Stop Enable
Provided LVDE = 1, this read/write bit determines whether the low-voltage detect function operates
when the MCU is in stop mode.
1 = Low-voltage detect enabled during stop mode.
0 = Low-voltage detect disabled during stop mode.
LVDE — Low-Voltage Detect Enable
This read/write bit enables low-voltage detect logic and qualifies the operation of other bits in this
register.
1 = LVD logic enabled.
0 = LVD logic disabled.
5.8.8 System Power Management Status and Control 2 Register (SPMSC2)
This register is used to report the status of the low voltage warning function, and to configure the stop mode
behavior of the MCU.
Bit 7 6 54321Bit 0
Read: LVWF 0
Write: LVWACK PPDACK
Power-on reset:
LVD reset:
Any other reset:
1
LVWF will be set in the case when V
V
.
LV W
Figure 5-9. System Power Management Status and Control 2 Register (SPMSC2)
LVDV LVWV
1
0
(1)
0
(1)
0
0
0 UU0000
0 UU0000
= Unimplemented or Reserved U = Unaffected by reset
transitions below the trip point or after reset and V
Supply
00
PPDF 0
PDC PPDC
0000
is already below
Supply
LVWF — Low-Voltage Warning Flag
The LVWF bit indicates the low-voltage warning status.
1 = Low voltage warning is present or was present.
0 = Low voltage warning not present.
LVWACK — Low-Voltage Warning Acknowledge
The LVWACK bit indicates the low-voltage warning acknowledge.
Writing a 1 to LVWACK clears LVWF to 0 if a low voltage warning is not present.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 75
Chapter 5 Resets, Interrupts, and System Configuration
LVDV — Low-Voltage Detect Voltage Select
The LVDV bit selects the LVD trip point voltage (V
1 = High trip point selected (V
0 = Low trip point selected (V
LVD
LVD
= V
= V
LVDH
LVDL
).
).
LVD
).
LVWV — Low-Voltage Warning Voltage Select
The LVWV bit selects the LVW trip point voltage (V
1 = High trip point selected (V
0 = Low trip point selected (V
LVW
LVW
= V
= V
LVWH
LVWL
).
).
LVW
).
PPDF — Partial Power Down Flag
The PPDF bit indicates that the MCU has exited the stop2 mode.
1 = Stop2 mode recovery.
0 = Not stop2 mode recovery.
PPDACK — Partial Power Down Acknowledge
Writing a 1 to PPDACK clears the PPDF bit.
PDC — Power Down Control
The write-once PDC bit controls entry into the power down (stop2 and stop1) modes.
1 = Power down modes are enabled.
0 = Power down modes are disabled.
PPDC — Partial Power Down Control
The write-once PPDC bit controls which power down mode, stop1 or stop2, is selected.
1 = Stop2, partial power down, mode enabled if PDC set.
0 = Stop1, full power down, mode enabled if PDC set.
MC9S08GB/GT Data Sheet, Rev. 2.3
76 Freescale Semiconductor
Chapter 6 Parallel Input/Output
6.1 Introduction
This section explains software controls related to parallel input/output (I/O). The MC9S08GBxx has seven
I/O ports which include a total of 56 general-purpose I/O pins (one of these pins is output only). The
MC9S08GTxx has six I/O ports which include a total of up to 39 general-purpose I/O pins, depending on
the package (one pin, PTG0, is output only). See Chapter 2, “Pins and Connections,” for more information
about the logic and hardware aspects of these pins.
Many of these pins are shared with on-chip peripherals such as timer systems, external interrupts, or
keyboard interrupts. When these other modules are not controlling the port pins, they revert to
general-purpose I/O control. For each I/O pin, a port data bit provides access to input (read) and output
(write) data, a data direction bit controls the direction of the pin, and a pullup enable bit enables an internal
pullup device (provided the pin is configured as an input), and a slew rate control bit controls the rise and
fall times of the pins.
NOTE
Not all general-purpose I/O pins are available on all packages. To avoid
extra current drain from floating input pins, the user’s reset initialization
routine in the application program should either enable on-chip pullup
devices or change the direction of unconnected pins to outputs so the pins
do not float.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 77
Chapter 6 Parallel Input/Output
RESET
NOTE 4
IRQ
NOTES 2, 3
V
DDAD
V
SSAD
V
REFH
V
REFL
HCS08 CORE
BDC
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION
POWER MANAGEMENT
RTI
IRQ LVD
USER FLASH
(GB60 = 61,268 BYTES)
(GB32 = 32,768 BYTES)
USER RAM
(GB60 = 4096 BYTES)
(GB32 = 2048 BYTES)
ANALOG-TO-DIGITAL
CONVERTER (ATD1)
INTERNAL CLOCK
GENERATOR (ICG)
LOW-POWER OSCILLATOR
CPU
COP
10-BIT
INTERNAL BUS
DEBUG
MODULE (DBG)
8-BIT KEYBOARD
INTERRUPT MODULE (KBI1)
IIC MODULE (IIC1)
SERIAL COMMUNICATIONS
INTERFACE MODULE (SCI1)
SERIAL COMMUNICATIONS
INTERFACE MODULE (SCI2)
3-CHANNEL TIMER/PWM
MODULE (TPM1)
5-CHANNEL TIMER/PWM
MODULE (TPM2)
SERIAL PERIPHERAL
INTERFACE MODULE (SPI1)
PORT A
PORT B
PORT C
PORT D
PORT E
PORT F
8
PTA7/KBI1P7–
PTA0/KBI1P0
8
PTB7/AD1P7–
PTB0/AD1P0
PTC7
PTC6
PTC5
PTC4
PTC3/SCL1
PTC2/SDA1
PTC1/RxD2
PTC0/TxD2
PTD7/TPM2CH4
PTD6/TPM2CH3
PTD5/TPM2CH2
PTD4/TPM2CH1
PTD3/TPM2CH0
PTD2/TPM1CH2
PTD1/TPM1CH1
PTD0/TPM1CH0
PTE7
PTE6
PTE5/SPSCK1
PTE4/MOSI1
PTE3/MISO1
PTE2/SS1
PTE1/RxD1
PTE0/TxD1
8
PTF7–PTF0
NOTES 1, 6
NOTE 1
NOTES 1, 5
NOTE 1
NOTE 1
NOTES 1, 5
V
DD
V
SS
VOLTAGE
REGULATOR
NOTES:
1. Port pins are software configurable with pullup device if input port.
2. Pin contains software configurable pullup/pulldown device if IRQ enabled
(IRQPE = 1).
3. IRQ does not have a clamp diode to V
4. Pin contains integrated pullup device.
. IRQ should not be driven above VDD.
DD
PORT G
PTG7
PTG6
PTG5
PTG4
PTG3
PTG2/EXTAL
PTG1/XTAL
PTG0/BKGD/MS
NOTE 1
5. High current drive
6. Pins PTA[7:4] contain both pullup and pulldown devices. Pulldown
available when KBI enabled (KBIPn = 1).
Figure 6-1. Block Diagram Highlighting Parallel Input/Output Pins
MC9S08GB/GT Data Sheet, Rev. 2.3
78 Freescale Semiconductor
6.2 Features
Parallel I/O features, depending on package choice, include:
• A total of 56 general-purpose I/O pins in seven ports (PTG0 is output only)
• High-current drivers on port C and port F pins
• Hysteresis input buffers
• Software-controlled pullups on each input pin
• Software-controlled slew rate output buffers
• Eight port A pins shared with KBI1
• Eight port B pins shared with ATD1
• Eight high-current port C pins shared with SCI2 and IIC1
• Eight port D pins shared with TPM1 and TPM2
• Eight port E pins shared with SCI1 and SPI1
• Eight high-current port F pins
• Eight port G pins shared with EXTAL, XTAL, and BKGD/MS
6.3 Pin Descriptions
Features
The MC9S08GB/GT has a total of 56 parallel I/O pins (one is output only) in seven 8-bit ports
(PTA–PTG). Not all pins are bonded out in all packages. Consult the pin assignment in Chapter 2, “Pins
and Connections,” for available parallel I/O pins. All of these pins are available for general-purpose I/O
when they are not used by other on-chip peripheral systems.
After reset, BKGD/MS is enabled and therefore is not usable as an output pin until BKGDPE in SOPT is
cleared. The rest of the peripheral functions are disabled. After reset, all data direction and pullup enable
controls are set to 0s. These pins default to being high-impedance inputs with on-chip pullup devices
disabled.
The following paragraphs discuss each port and the software controls that determine each pin’s use.
6.3.1 Port A and Keyboard Interrupts
Port A Bit 7 654321Bit 0
MCU Pin:
PTA7/
KBI1P7
Port A is an 8-bit port shared among the KBI keyboard interrupt inputs and general-purpose I/O. Any pins
enabled as KBI inputs will be forced to act as inputs.
PTA6/
KBI1P6
Figure 6-2. Port A Pin Names
PTA5/
KBI1P5
PTA4/
KBI1P4
PTA3/
KBI1P3
PTA2/
KBI1P2
PTA1/
KBI1P1
PTA0/
KBI1P0
Port A pins are available as general-purpose I/O pins controlled by the port A data (PTAD), data direction
(PTADD), pullup enable (PTAPE), and slew rate control (PTASE) registers. Refer to Section 6.4, “Parallel
I/O Controls,” for more information about general-purpose I/O control.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 79
Chapter 6 Parallel Input/Output
Port A can be configured to be keyboard interrupt input pins. Refer to Chapter 9, “Keyboard Interrupt
(KBI) Module,” for more information about using port A pins as keyboard interrupts pins.
6.3.2 Port B and Analog to Digital Converter Inputs
Port B Bit 7 654321Bit 0
MCU Pin:
PTB7/
AD1P7
PTB6/
AD1P6
Figure 6-3. Port B Pin Names
PTB5/
AD1P5
PTB4/
AD1P4
PTB3/
AD1P3
PTB2/
AD1P2
PTB1/
AD1P1
PTB0/
AD1P0
Port B is an 8-bit port shared among the ATD inputs and general-purpose I/O. Any pin enabled as an ATD
input will be forced to act as an input.
Port B pins are available as general-purpose I/O pins controlled by the port B data (PTBD), data direction
(PTBDD), pullup enable (PTBPE), and slew rate control (PTBSE) registers. Refer to Section 6.4, “Parallel
I/O Controls,” for more information about general-purpose I/O control.
When the ATD module is enabled, analog pin enables are used to specify which pins on port B will be used
as ATD inputs. Refer to Chapter 14, “Analog-to-Digital Converter (ATD) Module,” for more information
about using port B pins as ATD pins.
6.3.3 Port C and SCI2, IIC, and High-Current Drivers
Port C Bit 7 653321Bit 0
MCU Pin: PTC7 PTC6 PTC5 PTC4
Figure 6-4. Port C Pin Names
PTC3/
SCL1
PTC2/
SDA1
PTC1/
RxD2
PTC0/
TxD2
Port C is an 8-bit port which is shared among the SCI2 and IIC1 modules, and general-purpose I/O. When
SCI2 or IIC1 modules are enabled, the pin direction will be controlled by the module or function. Port C
has high current output drivers.
Port C pins are available as general-purpose I/O pins controlled by the port C data (PTCD), data direction
(PTCDD), pullup enable (PTCPE), and slew rate control (PTCSE) registers. Refer to Section 6.4, “Parallel
I/O Controls,” for more information about general-purpose I/O control.
When the SCI2 module is enabled, PTC0 serves as the SCI2 module’s transmit pin (TxD2) and PTC1
serves as the receive pin (RxD2). Refer to Chapter 11, “Serial Communications Interface (SCI) Module,”
for more information about using PTC0 and PTC1 as SCI pins
When the IIC module is enabled, PTC2 serves as the IIC modules’s serial data input/output pin (SDA1)
and PTC3 serves as the clock pin (SCL1). Refer to Chapter 13, “Inter-Integrated Circuit (IIC) Module,”
for more information about using PTC2 and PTC3 as IIC pins.
MC9S08GB/GT Data Sheet, Rev. 2.3
80 Freescale Semiconductor
6.3.4 Port D, TPM1 and TPM2
Port D Bit 7 654321Bit 0
Pin Descriptions
MCU Pin:
PTD7/
TPM2CH4
PTD6/
TPM2CH3
Figure 6-5. Port D Pin Names
PTD5/
TPM2CH2
PTD4/
TPM2CH1
PTD3/
TPM2CH0
PTD2/
TPM1CH2
PTD1/
TPM1CH1
PTD0/
TPM1CH0
Port D is an 8-bit port shared with the two TPM modules, TPM1 and TPM2, and general-purpose I/O.
When the TPM1 or TPM2 modules are enabled in output compare or input capture modes of operation,
the pin direction will be controlled by the module function.
Port D pins are available as general-purpose I/O pins controlled by the port D data (PTDD), data direction
(PTDDD), pullup enable (PTDPE), and slew rate control (PTDSE) registers. Refer to Section 6.4, “Parallel
I/O Controls” for more information about general-purpose I/O control.
The TPM2 module can be configured to use PTD7–PTD3 as either input capture, output compare, PWM,
or external clock input pins (PTD3 only). Refer to Chapter 10, “Timer/PWM (TPM) Module” for more
information about using PTD7–PTD3 as timer pins.
The TPM1 module can be configured to use PTD2–PTD0 as either input capture, output compare, PWM,
or external clock input pins (PTD0 only). Refer to Chapter 10, “Timer/PWM (TPM) Module” for more
information about using PTD2–PTD0 as timer pins.
6.3.5 Port E, SCI1, and SPI
Port E Bit 7 654321Bit 0
MCU Pin: PTE7 PTE6
Figure 6-6. Port E Pin Names
PTE5/
SPSCK1
PTE4/
MOSI1
PTE3/
MISO1
PTE2/
SS1
PTE1/
RxD1
PTE0/
TxD1
Port E is an 8-bit port shared with the SCI1 module, SPI1 module, and general-purpose I/O. When the SCI
or SPI modules are enabled, the pin direction will be controlled by the module function.
Port E pins are available as general-purpose I/O pins controlled by the port E data (PTED), data direction
(PTEDD), pullup enable (PTEPE), and slew rate control (PTESE) registers. Refer to Section 6.4, “Parallel
I/O Controls” for more information about general-purpose I/O control.
When the SCI1 module is enabled, PTE0 serves as the SCI1 module’s transmit pin (TxD1) and PTE1
serves as the receive pin (RxD1). Refer to Chapter 11, “Serial Communications Interface (SCI) Module”
for more information about using PTE0 and PTE1 as SCI pins.
When the SPI module is enabled, PTE2 serves as the SPI module’s slave select pin (
SS1), PTE3 serves as
the master-in slave-out pin (MISO1), PTE4 serves as the master-out slave-in pin (MOSI1), and PTE5
serves as the SPI clock pin (SPSCK1). Refer to Chapter 12, “Serial Peripheral Interface (SPI) Module for
more information about using PTE5–PTE2 as SPI pins.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 81
Chapter 6 Parallel Input/Output
6.3.6 Port F and High-Current Drivers
Port F Bit 7 654321Bit 0
MCU Pin: PTF7 PTF6 PTF5 PTF4 PTF3 PTF2 PTF1 PTF0
Figure 6-7. Port F Pin Names
Port F is an 8-bit port general-purpose I/O that is not shared with any peripheral module. Port F has high
current output drivers.
Port F pins are available as general-purpose I/O pins controlled by the port F data (PTFD), data direction
(PTFDD), pullup enable (PTFPE), and slew rate control (PTFSE) registers. Refer to Section 6.4, “Parallel
I/O Controls” for more information about general-purpose I/O control.
6.3.7 Port G, BKGD/MS, and Oscillator
Port G Bit 7 654321Bit 0
MCU Pin: PTG7 PTG6 PTG5 PTG4 PTG3
Figure 6-8. Port G Pin Names
PTG2/
EXTAL
PTG1/
XTAL
PTG0/
BKGD/MS
Port G is an 8-bit port which is shared among the background/mode select function, oscillator, and
general-purpose I/O. When the background/mode select function or oscillator is enabled, the pin direction
will be controlled by the module function.
Port G pins are available as general-purpose I/O pins controlled by the port G data (PTGD), data direction
(PTGDD), pullup enable (PTGPE), and slew rate control (PTGSE) registers. Refer to Section 6.4, “Parallel
I/O Controls” for more information about general-purpose I/O control.
The internal pullup for PTG0 is enabled when the background/mode select function is enabled, regardless
of the state of PTGPE0. During reset, the BKGD/MS pin functions as a mode select pin. After the MCU
is out of reset, the BKGD/MS pin becomes the background communications input/output pin. The PTG0
can be configured to be a general-purpose output pin. Refer to Chapter 3, “Modes of Operation”,
Chapter 5, “Resets, Interrupts, and System Configuration”, and Chapter 15, “Development Support” for
more information about using this pin.
The ICG module can be configured to use PTG2–PTG1 ports as crystal oscillator or external clock pins.
Refer to Chapter 13, “Inter-Integrated Circuit (IIC) Module” for more information about using these pins
as oscillator pins.
6.4 Parallel I/O Controls
Provided no on-chip peripheral is controlling a port pin, the pins operate as general-purpose I/O pins that
are accessed and controlled by a data register (PTxD), a data direction register (PTxDD), a pullup enable
register (PTxPE), and a slew rate control register (PTxSE) where x is A, B, C, D, E, F, or G.
MC9S08GB/GT Data Sheet, Rev. 2.3
82 Freescale Semiconductor
Parallel I/O Controls
Reads of the data register return the pin value (if PTxDDn = 0) or the contents of the port data register (if
PTxDDn = 1). Writes to the port data register are latched into the port register whether the pin is controlled
by an on-chip peripheral or the pin is configured as an input. If the corresponding pin is not controlled by
a peripheral and is configured as an output, this level will be driven out the port pin.
6.4.1 Data Direction Control
The data direction control bits determine whether the pin output driver is enabled, and they control what
is read for port data register reads. Each port pin has a data direction control bit. When PTxDDn = 0, the
corresponding pin is an input and reads of PTxD return the pin value. When PTxDDn = 1, the
corresponding pin is an output and reads of PTxD return the last value written to the port data register.
When a peripheral module or system function is in control of a port pin, the data direction control still
controls what is returned for reads of the port data register, even though the peripheral system has
overriding control of the actual pin direction.
For the MC9S08GB/GT MCU, reads of PTG0/BKGD/MS will return the value on the output pin.
It is a good programming practice to write to the port data register before changing the direction of a port
pin to become an output. This ensures that the pin will not be driven momentarily with an old data value
that happened to be in the port data register.
6.4.2 Internal Pullup Control
An internal pullup device can be enabled for each port pin that is configured as an input (PTxDDn = 0).
The pullup device is available for a peripheral module to use, provided the peripheral is enabled and is an
input function as long as the PTxDDn = 0.
For the four configurable KBI module inputs on PTA7–PTA4, when a pin is configured to detect rising
edges, the port pullup enable associated with the pin (PTAPEn) selects a pulldown rather than a pullup
device.
6.4.3 Slew Rate Control
Slew rate control can be enabled for each port pin that is configured as an output (PTxDDn = 1) or if a
peripheral module is enabled and its function is an output. Not all peripheral modules’ outputs have slew
rate control; refer to Chapter 2, “Pins and Connections” for more information about which pins have slew
rate control.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 83
Chapter 6 Parallel Input/Output
6.5 Stop Modes
Depending on the stop mode, I/O functions differently as the result of executing a STOP instruction. An
explanation of I/O behavior for the various stop modes follows:
• When the MCU enters stop1 mode, all internal registers including general-purpose I/O control and
data registers are powered down. All of the general-purpose I/O pins assume their reset state:
output buffers and pullups turned off. Upon exit from stop1, all I/O must be initialized as if the
MCU had been reset.
• When the MCU enters stop2 mode, the internal registers are powered down as in stop1 but the I/O
pin states are latched and held. For example, a port pin that is an output driving low continues to
function as an output driving low even though its associated data direction and output data registers
are powered down internally. Upon exit from stop2, the pins continue to hold their states until a 1
is written to the PPDACK bit. To avoid discontinuity in the pin state following exit from stop2, the
user must restore the port control and data registers to the values they held before entering stop2.
These values can be stored in RAM before entering stop2 because the RAM is maintained during
stop2.
• In stop3 mode, all I/O is maintained because internal logic circuity stays powered up. Upon
recovery, normal I/O function is available to the user.
6.6 Parallel I/O Registers and Control Bits
This section provides information about all registers and control bits associated with the parallel I/O ports.
Refer to tables in Chapter 4, “Memory” for the absolute address assignments for all parallel I/O registers.
This section refers to registers and control bits only by their names. A Freescale-provided equate or header
file normally is used to translate these names into the appropriate absolute addresses.
6.6.1 Port A Registers (PTAD, PTAPE, PTASE, and PTADD)
Port A includes eight pins shared between general-purpose I/O and the KBI module. Port A pins used as
general-purpose I/O pins are controlled by the port A data (PTAD), data direction (PTADD), pullup enable
(PTAPE), and slew rate control (PTASE) registers.
If the KBI takes control of a port A pin, the corresponding PTASE bit is ignored since the pin functions as
an input. As long as PTADD is 0, the PTAPE controls the pullup enable for the KBI function. Reads of
PTAD will return the logic value of the corresponding pin, provided PTADD is 0.
MC9S08GB/GT Data Sheet, Rev. 2.3
84 Freescale Semiconductor
Parallel I/O Registers and Control Bits
PTAD Bit 7 654321Bit 0
Read:
PTAD7 PTAD6 PTAD5 PTAD4 PTAD3 PTAD2 PTAD1 PTAD0
Write:
Reset: 00000000
PTAPE
Read:
PTAPE7 PTAPE6 PTAPE5 PTAPE4 PTAPE3 PTAPE2 PTAPE1 PTAPE0
Write:
Reset: 00000000
PTASE
Read:
PTASE7 PTASE6 PTASE5 PTASE4 PTASE3 PTASE2 PTASE1 PTASE0
Write:
Reset: 00000000
PTADD
Read:
PTADD7 PTADD6 PTADD5 PTADD4 PTADD3 PTADD2 PTADD1 PTADD0
Write:
Reset: 00000000
Figure 6-9. Port A Registers
PTADn — Port A Data Register Bit n (n = 0–7)
For port A pins that are inputs, reads return the logic level on the pin. For port A pins that are
configured as outputs, reads return the last value written to this register.
Writes are latched into all bits of this register. For port A pins that are configured as outputs, the logic
level is driven out the corresponding MCU pin.
Reset forces PTAD to all 0s, but these 0s are not driven out the corresponding pins because reset also
configures all port pins as high-impedance inputs with pullups disabled.
PTAPEn — Pullup Enable for Port A Bit n (n = 0–7)
For port A pins that are inputs, these read/write control bits determine whether internal pullup devices
are enabled provided the corresponding PTADDn is 0. For port A pins that are configured as outputs,
these bits are ignored and the internal pullup devices are disabled. When any of bits 7 through 4 of port
A are enabled as KBI inputs and are configured to detect rising edges/high levels, the pullup enable
bits enable pulldown rather than pullup devices.
1 = Internal pullup device enabled.
0 = Internal pullup device disabled.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 85
Chapter 6 Parallel Input/Output
PTASEn — Slew Rate Control Enable for Port A Bit n (n = 0–7)
For port A pins that are outputs, these read/write control bits determine whether the slew rate
controlled outputs are enabled. For port A pins that are configured as inputs, these bits are ignored.
1 = Slew rate control enabled.
0 = Slew rate control disabled.
PTADDn — Data Direction for Port A Bit n (n = 0–7)
These read/write bits control the direction of port A pins and what is read for PTAD reads.
1 = Output driver enabled for port A bit n and PTAD reads return the contents of PTADn.
0 = Input (output driver disabled) and reads return the pin value.
6.6.2 Port B Registers (PTBD, PTBPE, PTBSE, and PTBDD)
Port B includes eight general-purpose I/O pins that share with the ATD function. Port B pins used as
general-purpose I/O pins are controlled by the port B data (PTBD), data direction (PTBDD), pullup enable
(PTBPE), and slew rate control (PTBSE) registers.
If the ATD takes control of a port B pin, the corresponding PTBDD, PTBSE, and PTBPE bits are ignored.
When a port B pin is being used as an ATD pin, reads of PTBD will return a 0 of the corresponding pin,
provided PTBDD is 0.
PTBD Bit 7 654321Bit 0
Read:
PTBD7 PTBD6 PTBD5 PTBD4 PTBD3 PTBD2 PTBD1 PTBD0
Write:
Reset: 00000000
PTBPE
Read:
PTBPE7 PTBPE6 PTBPE5 PTBPE4 PTBPE3 PTBPE2 PTBPE1 PTBPE0
Write:
Reset: 00000000
PTBSE
Read:
PTBSE7 PTBSE6 PTBSE5 PTBSE4 PTBSE3 PTBSE2 PTBSE1 PTBSE0
Write:
Reset: 00000000
PTBDD
Read:
PTBDD7 PTBDD6 PTBDD5 PTBDD4 PTBDD3 PTBDD2 PTBDD1 PTBDD0
Write:
Reset: 00000000
Figure 6-10. Port B Registers
MC9S08GB/GT Data Sheet, Rev. 2.3
86 Freescale Semiconductor
Parallel I/O Registers and Control Bits
PTBDn — Port B Data Register Bit n (n = 0–7)
For port B pins that are inputs, reads return the logic level on the pin. For port B pins that are configured
as outputs, reads return the last value written to this register.
Writes are latched into all bits of this register. For port B pins that are configured as outputs, the logic
level is driven out the corresponding MCU pin.
Reset forces PTBD to all 0s, but these 0s are not driven out on the corresponding pins because reset
also configures all port pins as high-impedance inputs with pullups disabled.
PTBPEn — Pullup Enable for Port B Bit n (n = 0–7)
For port B pins that are inputs, these read/write control bits determine whether internal pullup devices
are enabled. For port B pins that are configured as outputs, these bits are ignored and the internal pullup
devices are disabled.
1 = Internal pullup device enabled.
0 = Internal pullup device disabled.
PTBSEn — Slew Rate Control Enable for Port B Bit n (n = 0–7)
For port B pins that are outputs, these read/write control bits determine whether the slew rate controlled
outputs are enabled. For port B pins that are configured as inputs, these bits are ignored.
1 = Slew rate control enabled.
0 = Slew rate control disabled.
PTBDDn — Data Direction for Port B Bit n (n = 0–7)
These read/write bits control the direction of port B pins and what is read for PTBD reads.
1 = Output driver enabled for port B bit n and PTBD reads return the contents of PTBDn.
0 = Input (output driver disabled) and reads return the pin value.
6.6.3 Port C Registers (PTCD, PTCPE, PTCSE, and PTCDD)
Port C includes eight general-purpose I/O pins that share with the SCI2 and IIC modules. Port C pins used
as general-purpose I/O pins are controlled by the port C data (PTCD), data direction (PTCDD), pullup
enable (PTCPE), and slew rate control (PTCSE) registers.
If the SCI2 takes control of a port C pin, the corresponding PTCDD bit is ignored. PTCSE can be used to
provide slew rate on the SCI2 transmit pin, TxD2. PTCPE can be used, provided the corresponding
PTCDD bit is 0, to provide a pullup device on the SCI2 receive pin, RxD2.
If the IIC takes control of a port C pin, the corresponding PTCDD bit is ignored. PTCSE can be used to
provide slew rate on the IIC serial data pin (SDA1), when in output mode and the IIC clock pin (SCL1).
PTCPE can be used, provided the corresponding PTCDD bit is 0, to provide a pullup device on the IIC
serial data pin, when in receive mode.
Reads of PTCD will return the logic value of the corresponding pin, provided PTCDD is 0.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 87
Chapter 6 Parallel Input/Output
PTCD Bit 7 654321Bit 0
PTCPE
PTCSE
PTCDD
Read:
PTCD7 PTCD6 PTCD5 PTCD4 PTCD3 PTCD2 PTCD1 PTCD0
Write:
Reset: 00000000
Read:
PTCPE7 PTCPE6 PTCPE5 PTCPE4 PTCPE3 PTCPE2 PTCPE1 PTCPE0
Write:
Reset: 00000000
Read:
PTCSE7 PTCSE6 PTCSE5 PTCSE4 PTCSE3 PTCSE2 PTCSE1 PTCSE0
Write:
Reset: 00000000
Read:
PTCDD7 PTCDD6 PTCDD5 PTCDD4 PTCDD3 PTCDD2 PTCDD1 PTCDD0
Write:
Reset: 00000000
Figure 6-11. Port C Registers
PTCDn — Port C Data Register Bit n (n = 0–7)
For port C pins that are inputs, reads return the logic level on the pin. For port C pins that are configured
as outputs, reads return the last value written to this register.
Writes are latched into all bits of this register. For port C pins that are configured as outputs, the logic
level is driven out the corresponding MCU pin.
Reset forces PTCD to all 0s, but these 0s are not driven out the corresponding pins because reset also
configures all port pins as high-impedance inputs with pullups disabled.
PTCPEn — Pullup Enable for Port C Bit n (n = 0–7)
For port C pins that are inputs, these read/write control bits determine whether internal pullup devices
are enabled. For port C pins that are configured as outputs, these bits are ignored and the internal pullup
devices are disabled.
1 = Internal pullup device enabled.
0 = Internal pullup device disabled.
PTCSEn — Slew Rate Control Enable for Port C Bit n (n = 0–7)
For port C pins that are outputs, these read/write control bits determine whether the slew rate controlled
outputs are enabled. For port B pins that are configured as inputs, these bits are ignored.
1 = Slew rate control enabled.
0 = Slew rate control disabled.
MC9S08GB/GT Data Sheet, Rev. 2.3
88 Freescale Semiconductor
Parallel I/O Registers and Control Bits
PTCDDn — Data Direction for Port C Bit n (n = 0–7)
These read/write bits control the direction of port C pins and what is read for PTCD reads.
1 = Output driver enabled for port C bit n and PTCD reads return the contents of PTCDn.
0 = Input (output driver disabled) and reads return the pin value.
6.6.4 Port D Registers (PTDD, PTDPE, PTDSE, and PTDDD)
Port D includes eight pins shared between general-purpose I/O, TPM1, and TPM2. Port D pins used as
general-purpose I/O pins are controlled by the port D data (PTDD), data direction (PTDDD), pullup enable
(PTDPE), and slew rate control (PTDSE) registers.
If a TPM takes control of a port D pin, the corresponding PTDDD bit is ignored. When the TPM is in
output compare mode, the corresponding PTDSE can be used to provide slew rate on the pin. When the
TPM is in input capture mode, the corresponding PTDPE can be used, provided the corresponding
PTDDD bit is 0, to provide a pullup device on the pin.
Reads of PTDD will return the logic value of the corresponding pin, provided PTDDD is 0.
PTDD Bit 7 654321Bit 0
Read:
PTDD7 PTDD6 PTDD5 PTDD4 PTDD3 PTDD2 PTDD1 PTDD0
Write:
PTDPE
PTDSE
PTDDD
Reset: 00000000
Read:
PTDPE7 PTDPE6 PTDPE5 PTDPE4 PTDPE3 PTDPE2 PTDPE1 PTDPE0
Write:
Reset: 00000000
Read:
PTDSE7 PTDSE6 PTDSE5 PTDSE4 PTDSE3 PTDSE2 PTDSE1 PTDSE0
Write:
Reset: 00000000
Read:
PTDDD7 PTDDD6 PTDDD5 PTDDD4 PTDDD3 PTDDD2 PTDDD1 PTDDD0
Write:
Reset: 00000000
Figure 6-12. Port D Registers
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 89
Chapter 6 Parallel Input/Output
PTDDn — Port D Data Register Bit n (n = 0–7)
For port D pins that are inputs, reads return the logic level on the pin. For port D pins that are
configured as outputs, reads return the last value written to this register.
Writes are latched into all bits of this register. For port D pins that are configured as outputs, the logic
level is driven out the corresponding MCU pin.
Reset forces PTDD to all 0s, but these 0s are not driven out the corresponding pins because reset also
configures all port pins as high-impedance inputs with pullups disabled.
PTDPEn — Pullup Enable for Port D Bit n (n = 0–7)
For port D pins that are inputs, these read/write control bits determine whether internal pullup devices
are enabled. For port D pins that are configured as outputs, these bits are ignored and the internal pullup
devices are disabled.
1 = Internal pullup device enabled.
0 = Internal pullup device disabled.
PTDSEn — Slew Rate Control Enable for Port D Bit n (n = 0–7)
For port D pins that are outputs, these read/write control bits determine whether the slew rate
controlled outputs are enabled. For port D pins that are configured as inputs, these bits are ignored.
1 = Slew rate control enabled.
0 = Slew rate control disabled.
PTDDDn — Data Direction for Port D Bit n (n = 0–7)
These read/write bits control the direction of port D pins and what is read for PTDD reads.
1 = Output driver enabled for port D bit n and PTDD reads return the contents of PTDDn.
0 = Input (output driver disabled) and reads return the pin value.
6.6.5 Port E Registers (PTED, PTEPE, PTESE, and PTEDD)
Port E includes eight general-purpose I/O pins that share with the SCI1 and SPI modules. Port E pins used
as general-purpose I/O pins are controlled by the port E data (PTED), data direction (PTEDD), pullup
enable (PTEPE), and slew rate control (PTESE) registers.
If the SCI1 takes control of a port E pin, the corresponding PTEDD bit is ignored. PTESE can be used to
provide slew rate on the SCI1 transmit pin, TxD1. PTEPE can be used, provided the corresponding
PTEDD bit is 0, to provide a pullup device on the SCI1 receive pin, RxD1.
If the SPI takes control of a port E pin, the corresponding PTEDD bit is ignored. PTESE can be used to
provide slew rate on the SPI serial output pin (MOSI1 or MISO1) and serial clock pin (SPSCK1)
depending on the SPI operational mode. PTEPE can be used, provided the corresponding PTEDD bit is 0,
to provide a pullup device on the SPI serial input pins (MOSI1 or MISO1) and slave select pin (
depending on the SPI operational mode.
Reads of PTED will return the logic value of the corresponding pin, provided PTEDD is 0.
SS1)
MC9S08GB/GT Data Sheet, Rev. 2.3
90 Freescale Semiconductor
Parallel I/O Registers and Control Bits
PTED Bit 7 654321Bit 0
PTEPE
PTESE
PTEDD
Read:
PTED7 PTED6 PTED5 PTED4 PTED3 PTED2 PTED1 PTED0
Write:
Reset: 00000000
Read:
PTEPE7 PTEPE6 PTEPE5 PTEPE4 PTEPE3 PTEPE2 PTEPE1 PTEPE0
Write:
Reset: 00000000
Read:
PTESE7 PTESE6 PTESE5 PTESE4 PTESE3 PTESE2 PTESE1 PTESE0
Write:
Reset: 00000000
Read:
PTEDD7 PTEDD6 PTEDD5 PTEDD4 PTEDD3 PTEDD2 PTEDD1 PTEDD0
Write:
Reset: 00000000
Figure 6-13. Port E Registers
PTEDn — Port E Data Register Bit n (n = 0–7)
For port E pins that are inputs, reads return the logic level on the pin. For port E pins that are configured
as outputs, reads return the last value written to this register.
Writes are latched into all bits in this register. For port E pins that are configured as outputs, the logic
level is driven out the corresponding MCU pin.
Reset forces PTED to all 0s, but these 0s are not driven out the corresponding pins because reset also
configures all port pins as high-impedance inputs with pullups disabled.
PTEPEn — Pullup Enable for Port E Bit n (n = 0–7)
For port E pins that are inputs, these read/write control bits determine whether internal pullup devices
are enabled. For port E pins that are configured as outputs, these bits are ignored and the internal pullup
devices are disabled.
1 = Internal pullup device enabled.
0 = Internal pullup device disabled.
PTESEn — Slew Rate Control Enable for Port E Bit n (n = 0–7)
For port E pins that are outputs, these read/write control bits determine whether the slew rate controlled
outputs are enabled. For port E pins that are configured as inputs, these bits are ignored.
1 = Slew rate control enabled.
0 = Slew rate control disabled.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 91
Chapter 6 Parallel Input/Output
PTEDDn — Data Direction for Port E Bit n (n = 0–7)
These read/write bits control the direction of port E pins and what is read for PTED reads.
1 = Output driver enabled for port E bit n and PTED reads return the contents of PTEDn.
0 = Input (output driver disabled) and reads return the pin value.
6.6.6 Port F Registers (PTFD, PTFPE, PTFSE, and PTFDD)
Port F includes eight general-purpose I/O pins that are not shared with any peripheral module. Port F pins
used as general-purpose I/O pins are controlled by the port F data (PTFD), data direction (PTFDD), pullup
enable (PTFPE), and slew rate control (PTFSE) registers.
PTFD Bit 7 654321Bit 0
Read:
PTFD7 PTFD6 PTFD5 PTFD4 PTFD3 PTFD2 PTFD1 PTFD0
Write:
Reset: 00000000
PTFPE
Read:
PTFPE7 PTFPE6 PTFPE5 PTFPE4 PTFPE3 PTFPE2 PTFPE1 PTFPE0
Write:
Reset: 00000000
PTFSE
Read:
PTFSE7 PTFSE6 PTFSE5 PTFSE4 PTFSE3 PTFSE2 PTFSE1 PTFSE0
Write:
Reset: 00000000
PTFDD
Read:
PTFDD7 PTFDD6 PTFDD5 PTFDD4 PTFDD3 PTFDD2 PTFDD1 PTFDD0
Write:
Reset: 00000000
Figure 6-14. Port F Registers
PTFDn — Port PTF Data Register Bit n (n = 0–7)
For port F pins that are inputs, reads return the logic level on the pin. For port F pins that are configured
as outputs, reads return the last value written to this register.
Writes are latched into all bits of this register. For port F pins that are configured as outputs, the logic
level is driven out the corresponding MCU pin.
Reset forces PTFD to all 0s, but these 0s are not driven out the corresponding pins because reset also
configures all port pins as high-impedance inputs with pullups disabled.
MC9S08GB/GT Data Sheet, Rev. 2.3
92 Freescale Semiconductor
Parallel I/O Registers and Control Bits
PTFPEn — Pullup Enable for Port F Bit n (n = 0–7)
For port F pins that are inputs, these read/write control bits determine whether internal pullup devices
are enabled. For port F pins that are configured as outputs, these bits are ignored and the internal pullup
devices are disabled.
1 = Internal pullup device enabled.
0 = Internal pullup device disabled.
PTFSEn — Slew Rate Control Enable for Port F Bit n (n = 0–7)
For port F pins that are outputs, these read/write control bits determine whether the slew rate controlled
outputs are enabled. For port F pins that are configured as inputs, these bits are ignored.
1 = Slew rate control enabled.
0 = Slew rate control disabled.
PTFDDn — Data Direction for Port F Bit n (n = 0–7)
These read/write bits control the direction of port F pins and what is read for PTFD reads.
1 = Output driver enabled for port F bit n and PTFD reads return the contents of PTFDn.
0 = Input (output driver disabled) and reads return the pin value.
6.6.7 Port G Registers (PTGD, PTGPE, PTGSE, and PTGDD)
Port G includes eight general-purpose I/O pins that are shared with BKGD/MS function and the oscillator
or external clock pins. Port G pins used as general-purpose I/O pins are controlled by the port G data
(PTGD), data direction (PTGDD), pullup enable (PTGPE), and slew rate control (PTGSE) registers.
Port pin PTG0, while in reset, defaults to the BKGD/MS pin. After the MCU is out of reset, PTG0 can be
configured to be a general-purpose output pin. When BKGD/MS takes control of PTG0, the corresponding
PTGDD, PTGPE, and PTGPSE bits are ignored.
Port pins PTG1 and PTG2 can be configured to be oscillator or external clock pins. When the oscillator
takes control of a port G pin, the corresponding PTGD, PTGDD, PTGSE, and PTGPE bits are ignored.
Reads of PTGD will return the logic value of the corresponding pin, provided PTGDD is 0.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 93
Chapter 6 Parallel Input/Output
PTGD Bit 7 654321Bit 0
PTGPE
PTGSE
PTGDD
Read:
PTGD7 PTGD6 PTGD5 PTGD4 PTGD3 PTGD2 PTGD1 PTGD0
Write:
Reset: 00000000
Read:
PTGPE7 PTGPE6 PTGPE5 PTGPE4 PTGPE3 PTGPE2 PTGPE1 PTGPE0
Write:
Reset: 00000000
Read:
PTGSE7 PTGSE6 PTGSE5 PTGSE4 PTGSE3 PTGSE2 PTGSE1 PTGSE0
Write:
Reset: 00000000
Read:
PTGDD7 PTGDD6 PTGDD5 PTGDD4 PTGDD3 PTGDD2 PTGDD1 PTGDD0
Write:
Reset: 00000000
Figure 6-15. Port G Registers
PTGDn — Port PTG Data Register Bit n (n = 0–7)
For port G pins that are inputs, reads return the logic level on the pin. For port G pins that are
configured as outputs, reads return the last value written to this register.
Writes are latched into all bits of this register. For port G pins that are configured as outputs, the logic
level is driven out the corresponding MCU pin.
Reset forces PTGD to all 0s, but these 0s are not driven out the corresponding pins because reset also
configures all port pins as high-impedance inputs with pullups disabled.
PTGPEn — Pullup Enable for Port G Bit n (n = 0–7)
For port G pins that are inputs, these read/write control bits determine whether internal pullup devices
are enabled. For port G pins that are configured as outputs, these bits are ignored and the internal pullup
devices are disabled.
1 = Internal pullup device enabled.
0 = Internal pullup device disabled.
PTGSEn — Slew Rate Control Enable for Port G Bit n (n = 0–7)
For port G pins that are outputs, these read/write control bits determine whether the slew rate
controlled outputs are enabled. For port G pins that are configured as inputs, these bits are ignored.
1 = Slew rate control enabled.
0 = Slew rate control disabled.
MC9S08GB/GT Data Sheet, Rev. 2.3
94 Freescale Semiconductor
Parallel I/O Registers and Control Bits
PTGDDn — Data Direction for Port G Bit n (n = 0–7)
These read/write bits control the direction of port G pins and what is read for PTGD reads.
1 = Output driver enabled for port G bit n and PTGD reads return the contents of PTGDn.
0 = Input (output driver disabled) and reads return the pin value.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 95
Chapter 6 Parallel Input/Output
MC9S08GB/GT Data Sheet, Rev. 2.3
96 Freescale Semiconductor
Chapter 7 Internal Clock Generator (ICG) Module
The MC9S08GB/GT microcontroller provides one internal clock generation (ICG) module to create the
system bus frequency. All functions described in this section are available on the MC9S08GB/GT
microcontroller. The EXTAL and XTAL pins share port G bits 2 and 1, respectively. Analog supply lines
DDA
and V
V
the ICG may be found in Appendix A, “Electrical Characteristics.”
are internally derived from the MCU’s VDDand VSSpins. Electrical parametric data for
SSA
ICG
ICGERCLK
FFE
SYSTEM
CONTROL
LOGIC
RTI
TPM1 TPM2 IIC1 SCI1 SCI2 SPI1
÷2
FIXED FREQ CLOCK (XCLK)
ICGOUT
ICGLCLK*
* ICGLCLK is the alternate BDC clock source for the MC9S08GB/GT.
÷2
CPU
BUSCLK
BDC
Figure 7-1. System Clock Distribution Diagram
NOTE
ATD1
ATD has min and max
frequency requirements.
See Chapter 1, “Introduction”
and Appendix A, “Electrical
Characteristics.
RAM FLASH
FLASH has frequency
requirements for program
and erase operation.
See Appendix A, “Electrical
Characteristics.
Freescale Semiconductor recommends that FLASH location $FFBE be
reserved to store a nonvolatile version of ICGTRM. This will allow
debugger and programmer vendors to perform a manual trim operation and
store the resultant ICGTRM value for users to access at a later time.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 97
Chapter 7 Internal Clock Generator (ICG) Module
RESET
NOTE 4
IRQ
NOTES 2, 3
V
DDAD
V
SSAD
V
REFH
V
REFL
HCS08 CORE
BDC
HCS08 SYSTEM CONTROL
RESETS AND INTERRUPTS
MODES OF OPERATION
POWER MANAGEMENT
RTI
IRQ LVD
USER FLASH
(GB60 = 61,268 BYTES)
(GB32 = 32,768 BYTES)
USER RAM
(GB60 = 4096 BYTES)
(GB32 = 2048 BYTES)
ANALOG-TO-DIGITAL
CONVERTER (ATD1)
INTERNAL CLOCK
GENERATOR (ICG)
LOW-POWER OSCILLATOR
CPU
COP
10-BIT
INTERNAL BUS
DEBUG
MODULE (DBG)
8-BIT KEYBOARD
INTERRUPT MODULE (KBI1)
IIC MODULE (IIC1)
SERIAL COMMUNICATIONS
INTERFACE MODULE (SCI1)
SERIAL COMMUNICATIONS
INTERFACE MODULE (SCI2)
3-CHANNEL TIMER/PWM
MODULE (TPM1)
5-CHANNEL TIMER/PWM
MODULE (TPM2)
SERIAL PERIPHERAL
INTERFACE MODULE (SPI1)
PORT A
PORT B
PORT C
PORT D
PORT E
PORT F
8
PTA7/KBI1P7–
PTA0/KBI1P0
8
PTB7/AD1P7–
PTB0/AD1P0
PTC7
PTC6
PTC5
PTC4
PTC3/SCL1
PTC2/SDA1
PTC1/RxD2
PTC0/TxD2
PTD7/TPM2CH4
PTD6/TPM2CH3
PTD5/TPM2CH2
PTD4/TPM2CH1
PTD3/TPM2CH0
PTD2/TPM1CH2
PTD1/TPM1CH1
PTD0/TPM1CH0
PTE7
PTE6
PTE5/SPSCK1
PTE4/MOSI1
PTE3/MISO1
PTE2/SS1
PTE1/RxD1
PTE0/TxD1
8
PTF7–PTF0
NOTES 1, 6
NOTE 1
NOTES 1, 5
NOTE 1
NOTE 1
NOTES 1, 5
V
DD
V
SS
VOLTAGE
REGULATOR
NOTES:
1. Port pins are software configurable with pullup device if input port.
2. Pin contains software configurable pullup/pulldown device if IRQ
enabled (IRQPE = 1).
3. IRQ does not have a clamp diode to V
above V
4. Pin contains integrated pullup device.
DD
.
. IRQ should not be driven
DD
PORT G
PTG7
PTG6
PTG5
PTG4
PTG3
PTG2/EXTAL
PTG1/XTAL
PTG0/BKGD/MS
NOTE 1
5. High current drive
6. Pins PTA[7:4] contain both pullup and pulldown devices. Pulldown
available when KBI enabled (KBIPn = 1).
Figure 7-2. Block Diagram Highlighting ICG Module
MC9S08GB/GT Data Sheet, Rev. 2.3
98 Freescale Semiconductor
Introduction
7.1 Introduction
Figure 7-3 is a top-level diagram that shows the functional organization of the internal clock generation
(ICG) module. This section includes a general description and a feature list.
EXTAL
ICG
DCO
ICGDCLK
CLOCK
SELECT
OUTPUT
CLOCK
SELECT
FIXED
CLOCK
SELECT
/R
FFE
ICGLCLK
ICGOUT
XTAL
V
DDA
(SEE NOTE 2)
V
SSA
(SEE NOTE 2)
OSCILLATOR (OSC)
WITH EXTERNAL REF
SELECT
INTERNAL
REFERENCE
GENERATORS
TYP 243 kHz
IRG
8 MHz
RG
ICGERCLK
FREQUENCY
REF
SELECT
LOCKED
LOOP (FLL)
LOSS OF LOCK
AND CLOCK DETECTOR
ICGIRCLK
LOCAL CLOCK FOR OPTIONAL USE WITH BDC
NOTES:
1. See Figure 7-1 for specific use of ICGOUT, FFE, ICGLCLK, ICGERCLK
2. Not all HCS08 microcontrollers have unique supply pins for the ICG. See the device pin assignments in
the Pins and Connections section for specifics.
Figure 7-3. ICG Block Diagram
The ICG provides multiple options for clock sources. This offers a user great flexibility when making
choices between cost, precision, current draw, and performance. As seen in Figure 7-3, the ICG consists
of four functional blocks. Each of these is briefly described here and then in more detail in a later section.
• Oscillator block — The oscillator block provides means for connecting an external crystal or
resonator. Two frequency ranges are software selectable to allow optimal startup and stability.
Alternatively, the oscillator block can be used to route an external square wave to the system clock.
External sources can provide a very precise clock source.
• Internal reference generator — The internal reference generator consists of two controlled clock
sources. One is designed to be approximately 8 MHz and can be selected as a local clock for the
background debug controller. The other internal reference clock source is typically 243 kHz and
can be trimmed for finer accuracy via software when a precise timed event is input to the MCU.
This provides a highly reliable, low-cost clock source.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor 99
Internal Clock Generator (ICG) Module
• Frequency-locked loop — A frequency-locked loop (FLL) stage takes either the internal or
external clock source and multiplies it to a higher frequency. Status bits provide information when
the circuit has achieved lock and when it falls out of lock. Additionally, this block can monitor the
external reference clock and signals whether the clock is valid or not.
• Clock select block — The clock select block provides several switch options for connecting
different clock sources to the system clock tree. ICGDCLK is the multiplied clock frequency out
of the FLL, ICGERCLK is the reference clock frequency from the crystal or external clock source,
and FFE (fixed frequency enable) is a control signal used to control the system fixed frequency
clock (XCLK). ICGLCLK is the clock source for the background debug controller (BDC).
The module is intended to be very user friendly with many of the features occurring automatically without
user intervention. To quickly configure the module, go to Section 7.4, “Initialization/Application
Information,” and pick an example that best suits the application needs.
7.1.1 Features
Features of the ICG and clock distribution system:
• Several options for the primary clock source allow a wide range of cost, frequency, and precision
choices:
— 32 kHz–100 kHz crystal or resonator
— 1 MHz–16 MHz crystal or resonator
— External clock
— Internal reference generator
• Defaults to self-clocked mode to minimize startup delays
• Frequency-locked loop (FLL) generates 8 MHz to 40 MHz (for bus rates up to 20 MHz)
— Uses external or internal clock as reference frequency
• Automatic lockout of non-running clock sources
• Reset or interrupt on loss of clock or loss of FLL lock
• Digitally-controlled oscillator (DCO) preserves previous frequency settings, allowing fast
frequency lock when recovering from stop3 mode
• DCO will maintain operating frequency during a loss or removal of reference clock
• Post-FLL divider selects 1 of 8 bus rate divisors (/1 through /128)
• Separate self-clocked source for real-time interrupt
• Trimmable internal clock source supports SCI communications without additional external
components
• Automatic FLL engagement after lock is acquired
MC9S08GB/GT Data Sheet, Rev. 2.3
100 Freescale Semiconductor
Loading...