Freescale MC68HC908QY4, MC68HC908QY2, MC68HC908QT2, MC68HC908QY1, MC68HC908QT1 DATA SHEET

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Data Sheet

M68HC08 Microcontrollers

MC68HC908QY4/D Rev. 5

07/2005

freescale.com

MC68HC908QY4 MC68HC908QT4 MC68HC908QY2 MC68HC908QT2 MC68HC908QY1 MC68HC908QT1

Data Sheet

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Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. This product incorporates SuperFlash® technology licensed from SST.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 3

Revision History

The following revision history table summarizes changes contained in this document. For your convenience, the page number designators have been linked to the appropriate location.

Revision History (Sheet 1 of 3)

Date

September,

2002

December,

2002

January,

2003

Revision

Level

N/A Initial release N/A

1.2 Features — Added 8-pin dual flat no lead (DFN) packages to features list. 19

Figure 1-2. MCU Pin Assignments — Figure updated to include DFN packages. 21

Figure 2-1. Memory Map — Clarified illegal address and unimplemented memory.

Figure 2-2. Control, Status, and Data Registers — Corrected bit definitions for Port A Data Register (PTA) and Data Direction Register A (DDRA).

Table 13-3. Interrupt Sources — Corrected vector addresses for keyboard interrupt and ADC conversion complete interrupt.

Chapter 13 System Integration Module (SIM) — Removed reference to break status register as it is duplicated in break module.

11.3.1 Internal Oscillator and 11.3.1.1 Internal Oscillator Trimming — Clarified oscillator trim option ordering information and what to expect with untrimmed device.

Figure 11-5. Oscillator Trim Register (OSCTRIM) — Bit 1 designation corrected. 98

Figure 15-13. Monitor Mode Circuit (Internal Clock, No High Voltage) —

0.1

0.2 4.2 Features — Corrected third bulleted item. 49

Diagram updated for clarity.

Figure 12-1. I/O Port Register Summary — Corrected bit definitions for PTA7, DDRA7, and DDRA6.

Figure 12-2. Port A Data Register (PTA) — Corrected bit definition for PTA7. 100

Figure 12-3. Data Direction Register A (DDRA) — Corrected bit definitions for DDRA7 and DDRA6.

Figure 12-6. Port B Data Register (PTB) — Corrected bit definition for PTB1 103

Chapter 9 Keyboard Interrupt Module (KBI) — Section reworked after deletion of auto wakeup for clarity.

Chapter 4 Auto Wakeup Module (AWU) — New section added for clarity. 49

Figure 10-1. LVI Module Block Diagram — Corrected LVI stop representation. 87

Chapter 16 Electrical Specifications — Extensive changes made to electrical specifications.

17.5 8-Pin Dual Flat No Lead (DFN) Package (Case #1452) — Added case outline drawing for DFN package.

Chapter 17 Ordering Information and Mechanical Specifications — Added ordering information for DFN package.

Description

Page

Number(s)

118

113

150

101

169

177

185

MC68HC908QY/QT Family Data Sheet, Rev. 5

4 Freescale Semiconductor

Revision History (Sheet 2 of 3)

Date

August,

2003

October,

2003

January,

2004

Revision

Level

1.0

2.0

3.0

Description

Reformatted to meet latest M68HC08 documentation standards N/A

Figure 1-1. Block Diagram — Diagram redrawn to include keyboard interrupt module and TCLK pin designator.

Figure 1-2. MCU Pin Assignments — Added TCLK pin designator. 21

Table 1-2. Pin Functions — Added TCLK pin description. 22

Table 1-3. Function Priority in Shared Pins — Revised table for clarity and to add TCLK.

Figure 2-1. Memory Map — Corrected names for the IRQ status and control register (INTSCR) bits 3–0.

3.7.3 ADC Input Clock Register — Clarified bit description for the ADC clock prescaler bits.

4.3 Functional Description — Updated periodic wakeup request values. 51

Figure 6-1. COP Block Diagram — Reworked for clarity 59

Chapter 8 External Interrupt (IRQ) — Corrected bit names for MODE, IRQF, ACK, and IMASK

Chapter 14 Timer Interface Module (TIM) — Added TCLK function. 131–139

15.3 Monitor Module (MON) — Updated with additional data. 147

Chapter 16 Electrical Specifications — Updated with additional data. 169–173

Figure 2-2. Control, Status, and Data Registers — Deleted unimplemented areas from $FFB0–$FFBD and $FFC2–$FFCF as they are actually available. Also corrected $FFBF designation from unimplemented to reserved.

Figure 6-1. COP Block Diagram — Reworked for clarity 59

6.3.2 STOP Instruction — Added subsection 60

13.4.2 Active Resets from Internal Sources — Reworked notes for clarity. 111

Table 13-2. Reset Recovery Timing — Replaced previous table with new information.

Chapter 14 Timer Interface Module (TIM) — Updated with additional data. 131

Figure 15-3. Break I/O Register Summary — Corrected bit designators for the BRKAR register

15.3 Monitor Module (MON) — Clarified seventh bullet. 147

Table 17-1. MC Order Numbers — Corrected temperature and package designators.

Figure 2-2. Control, Status, and Data Registers — Corrected reset state for the FLASH Block Protect Register at address location $FFBE and the Internal Oscillator Trim Value at $FFC0.

Figure 2-5. FLASH Block Protect Register (FLBPR) — Restated reset state for clarity.

Page

Number(s)

77–79

112

143

175

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 5

Revision History

Revision History (Sheet 3 of 3)

Date

November,

2004

July,

2005

Revision

Level

4.0

5.0

Description

Reformatted to meet current documentation standards Throughout

6.3.1 BUSCLKX4 — Clarified description of BUSCLKX4 58

Chapter 7 Central Processor Unit (CPU) — In 7.7 Instruction Set Summary:

Reworked definitions for STOP instruction Added WAIT instruction

13.8.1 SIM Reset Status Register — Clarified SRSR flag setting 117

14.9.1 TIM Status and Control Register — Added information to TSTOP note 127

16.8 5-V Oscillator Characteristics — Added values for deviation from trimmed inernal oscillator

16.12 3-V Oscillator Characteristics — Added values for deviation from trimmed inernal oscillator

Figure 5-2. Configuration Register 1 (CONFIG1) — Clarified bit definitions for

COPRS.

Chapter 8 External Interrupt (IRQ) — Reworked for clarification. 73

11.3.4 RC Oscillator — Improved RC oscillator wording. 93

12.1 Introduction — Added note pertaining to non-bonded port pins. 97

17.3 Package Dimensions — Updated package information. 165

Page

Number(s)

70 71

155

158

MC68HC908QY/QT Family Data Sheet, Rev. 5

6 Freescale Semiconductor

List of Chapters

Chapter 1 General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Chapter 2 Memory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

Chapter 3 Analog-to-Digital Converter (ADC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Chapter 4 Auto Wakeup Module (AWU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49

Chapter 5 Configuration Register (CONFIG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53

Chapter 6 Computer Operating Properly (COP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57

Chapter 7 Central Processor Unit (CPU). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61

Chapter 8 External Interrupt (IRQ). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73

Chapter 9 Keyboard Interrupt Module (KBI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79

Chapter 10 Low-Voltage Inhibit (LVI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Chapter 11 Oscillator Module (OSC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89

Chapter 12 Input/Output Ports (PORTS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97

Chapter 13 System Integration Module (SIM). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103

Chapter 14 Timer Interface Module (TIM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119

Chapter 15 Development Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133

Chapter 16 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .149

Chapter 17 Ordering Information and Mechanical Specifications . . . . . . . . . . . . . . . . . .165

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 7

List of Chapters

MC68HC908QY/QT Family Data Sheet, Rev. 5

8 Freescale Semiconductor

Table of Contents

Chapter 1

General Description

1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

1.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

1.3 MCU Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

1.4 Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

1.5 Pin Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

1.6 Pin Function Priority. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Chapter 2

Memory

2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

2.2 Unimplemented Memory Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

2.3 Reserved Memory Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

2.4 Input/Output (I/O) Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

2.5 Random-Access Memory (RAM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2.6 FLASH Memory (FLASH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

2.6.1 FLASH Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

2.6.2 FLASH Page Erase Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2.6.3 FLASH Mass Erase Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.6.4 FLASH Program Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.6.5 FLASH Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

2.6.6 FLASH Block Protect Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

2.6.7 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

2.6.8 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Chapter 3

Analog-to-Digital Converter (ADC)

3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

3.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

3.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

3.3.1 ADC Port I/O Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

3.3.2 Voltage Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

3.3.3 Conversion Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

3.3.4 Continuous Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

3.3.5 Accuracy and Precision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

3.4 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

3.5 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

3.5.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

3.5.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 9

Table of Contents

3.6 Input/Output Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.7 Input/Output Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.7.1 ADC Status and Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.7.2 ADC Data Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

3.7.3 ADC Input Clock Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Chapter 4

Auto Wakeup Module (AWU)

4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

4.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

4.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

4.4 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

4.5 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

4.6 Input/Output Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

4.6.1 Port A I/O Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

4.6.2 Keyboard Status and Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

4.6.3 Keyboard Interrupt Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Chapter 5

Configuration Register (CONFIG)

5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

5.2 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Chapter 6

Computer Operating Properly (COP)

6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

6.2 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

6.3 I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.3.1 BUSCLKX4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.3.2 STOP Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.3.3 COPCTL Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.3.4 Power-On Reset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.3.5 Internal Reset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.3.6 COPD (COP Disable). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.3.7 COPRS (COP Rate Select) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6.4 COP Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6.6 Monitor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6.7 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6.7.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6.7.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6.8 COP Module During Break Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

MC68HC908QY/QT Family Data Sheet, Rev. 5

10 Freescale Semiconductor

Chapter 7

Central Processor Unit (CPU)

7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

7.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

7.3 CPU Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

7.3.1 Accumulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

7.3.2 Index Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

7.3.3 Stack Pointer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

7.3.4 Program Counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

7.3.5 Condition Code Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

7.4 Arithmetic/Logic Unit (ALU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

7.5 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

7.5.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

7.5.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

7.6 CPU During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

7.7 Instruction Set Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

7.8 Opcode Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Chapter 8

External Interrupt (IRQ)

8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

8.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

8.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

8.3.1 MODE = 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

8.3.2 MODE = 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

8.4 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

8.5 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

8.5.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

8.5.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

8.6 IRQ Module During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

8.7 I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

8.7.1 IRQ Input Pins (IRQ

8.8 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Chapter 9

Keyboard Interrupt Module (KBI)

9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

9.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

9.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

9.3.1 Keyboard Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

9.3.2 Keyboard Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

9.4 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

9.5 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

9.6 Keyboard Module During Break Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

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9.7 Input/Output Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

9.7.1 Keyboard Status and Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

9.7.2 Keyboard Interrupt Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Chapter 10

Low-Voltage Inhibit (LVI)

10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

10.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

10.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

10.3.1 Polled LVI Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

10.3.2 Forced Reset Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

10.3.3 Voltage Hysteresis Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

10.3.4 LVI Trip Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

10.4 LVI Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

10.5 LVI Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

10.6 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

10.6.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

10.6.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Chapter 11

Oscillator Module (OSC)

11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

11.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

11.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

11.3.1 Internal Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

11.3.1.1 Internal Oscillator Trimming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

11.3.1.2 Internal to External Clock Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

11.3.2 External Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

11.3.3 XTAL Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

11.3.4 RC Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

11.4 Oscillator Module Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

11.4.1 Crystal Amplifier Input Pin (OSC1). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

11.4.2 Crystal Amplifier Output Pin (OSC2/PTA4/BUSCLKX4) . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

11.4.3 Oscillator Enable Signal (SIMOSCEN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

11.4.4 XTAL Oscillator Clock (XTALCLK). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

11.4.5 RC Oscillator Clock (RCCLK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

11.4.6 Internal Oscillator Clock (INTCLK). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

11.4.7 Oscillator Out 2 (BUSCLKX4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

11.4.8 Oscillator Out (BUSCLKX2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

11.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

11.5.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

11.5.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

11.6 Oscillator During Break Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

11.7 CONFIG2 Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

11.8 Input/Output (I/O) Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

11.8.1 Oscillator Status Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

11.8.2 Oscillator Trim Register (OSCTRIM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

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Chapter 12

Input/Output Ports (PORTS)

12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

12.2 Port A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

12.2.1 Port A Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

12.2.2 Data Direction Register A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

12.2.3 Port A Input Pullup Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

12.3 Port B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

12.3.1 Port B Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

12.3.2 Data Direction Register B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

12.3.3 Port B Input Pullup Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Chapter 13

System Integration Module (SIM)

13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

13.2 RST

13.3 SIM Bus Clock Control and Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

13.3.1 Bus Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

13.3.2 Clock Start-Up from POR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

13.3.3 Clocks in Stop Mode and Wait Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

13.4 Reset and System Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

13.4.1 External Pin Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

13.4.2 Active Resets from Internal Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

13.4.2.1 Power-On Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

13.4.2.2 Computer Operating Properly (COP) Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

13.4.2.3 Illegal Opcode Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

13.4.2.4 Illegal Address Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

13.4.2.5 Low-Voltage Inhibit (LVI) Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

13.5 SIM Counter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

13.5.1 SIM Counter During Power-On Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

13.5.2 SIM Counter During Stop Mode Recovery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

13.5.3 SIM Counter and Reset States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

13.6 Exception Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

13.6.1 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

13.6.1.1 Hardware Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

13.6.1.2 SWI Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

13.6.2 Interrupt Status Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

13.6.2.1 Interrupt Status Register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

13.6.2.2 Interrupt Status Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

13.6.2.3 Interrupt Status Register 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

13.6.3 Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

13.6.4 Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

13.6.5 Status Flag Protection in Break Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

13.7 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

13.7.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

13.7.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

and IRQ Pins Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

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13.8 SIM Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

13.8.1 SIM Reset Status Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

13.8.2 Break Flag Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Chapter 14

Timer Interface Module (TIM)

14.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

14.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

14.3 Pin Name Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

14.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

14.4.1 TIM Counter Prescaler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

14.4.2 Input Capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

14.4.3 Output Compare. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

14.4.3.1 Unbuffered Output Compare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

14.4.3.2 Buffered Output Compare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

14.4.4 Pulse Width Modulation (PWM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

14.4.4.1 Unbuffered PWM Signal Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

14.4.4.2 Buffered PWM Signal Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

14.4.4.3 PWM Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

14.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

14.6 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

14.7 TIM During Break Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

14.8 Input/Output Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

14.8.1 TIM Clock Pin (PTA2/TCLK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

14.8.2 TIM Channel I/O Pins (PTA0/TCH0 and PTA1/TCH1). . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

14.9 Input/Output Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

14.9.1 TIM Status and Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

14.9.2 TIM Counter Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

14.9.3 TIM Counter Modulo Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

14.9.4 TIM Channel Status and Control Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

14.9.5 TIM Channel Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

Chapter 15

Development Support

15.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

15.2 Break Module (BRK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

15.2.1 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

15.2.1.1 Flag Protection During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

15.2.1.2 TIM During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

15.2.1.3 COP During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

15.2.2 Break Module Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

15.2.2.1 Break Status and Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

15.2.2.2 Break Address Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

15.2.2.3 Break Auxiliary Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

15.2.2.4 Break Status Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

15.2.2.5 Break Flag Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

15.2.3 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

MC68HC908QY/QT Family Data Sheet, Rev. 5

14 Freescale Semiconductor

15.3 Monitor Module (MON) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

15.3.1 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

15.3.1.1 Normal Monitor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

15.3.1.2 Forced Monitor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

15.3.1.3 Monitor Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

15.3.1.4 Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

15.3.1.5 Break Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

15.3.1.6 Baud Rate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

15.3.1.7 Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

15.3.2 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

Chapter 16

Electrical Specifications

16.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

16.2 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

16.3 Functional Operating Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

16.4 Thermal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

16.5 5-V DC Electrical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

16.6 Typical 5-V Output Drive Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

16.7 5-V Control Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

16.8 5-V Oscillator Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

16.9 3-V DC Electrical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

16.10 Typical 3.0-V Output Drive Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

16.11 3-V Control Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

16.12 3-V Oscillator Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

16.13 Supply Current Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

16.14 Analog-to-Digital Converter Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

16.15 Timer Interface Module Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

16.16 Memory Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

Chapter 17

Ordering Information and Mechanical Specifications

17.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

17.2 MC Order Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

17.3 Package Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 15

Table of Contents

MC68HC908QY/QT Family Data Sheet, Rev. 5

16 Freescale Semiconductor

Chapter 1 General Description

1.1 Introduction

The MC68HC908QY4 is a member of the low-cost, high-performance M68HC08 Family of 8-bit microcontroller units (MCUs). The M68HC08 Family is a Complex Instruction Set Computer (CISC) with a Von Neumann architecture. All MCUs in the family use the enhanced M68HC08 central processor unit (CPU08) and are available with a variety of modules, memory sizes and types, and package types.

0.4

Table 1-1. Summary of Device Variations

Device

MC68HC908QT1 1536 bytes — 8 pins

MC68HC908QT2 1536 bytes 4 ch, 8 bit 8 pins

MC68HC908QT4 4096 bytes 4 ch, 8 bit 8 pins

MC68HC908QY1 1536 bytes — 16 pins

MC68HC908QY2 1536 bytes 4 ch, 8 bit 16 pins

MC68HC908QY4 4096 bytes 4 ch, 8 bit 16 pins

FLASH

Memory Size

Analog-to-Digital

Converter

1.2 Features

Features include:

• High-performance M68HC08 CPU core

• Fully upward-compatible object code with M68HC05 Family

• 5-V and 3-V operating voltages (V

• 8-MHz internal bus operation at 5 V, 4-MHz at 3 V

• Trimmable internal oscillator – 3.2 MHz internal bus operation – 8-bit trim capability allows 0.4% accuracy – ± 25% untrimmed

• Auto wakeup from STOP capability

• Configuration (CONFIG) register for MCU configuration options, including: – Low-voltage inhibit (LVI) trip point

• In-system FLASH programming

• FLASH security

(2)

)

(1)

Count

1. The oscillator frequency is guaranteed to ±5% over temperature and voltage range after trimming.

2. No security feature is absolutely secure. However, Freescale’s strategy is to make reading or copying the FLASH difficult for unauthorized users.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 17

General Description

• On-chip in-application programmable FLASH memory (with internal program/erase voltage generation) – MC68HC908QY4 and MC68HC908QT4 — 4096 bytes – MC68HC908QY2, MC68HC908QY1, MC68HC908QT2, and MC68HC908QT1 — 1536 bytes

• 128 bytes of on-chip random-access memory (RAM)

• 2-channel, 16-bit timer interface module (TIM)

• 4-channel, 8-bit analog-to-digital converter (ADC) on MC68HC908QY2, MC68HC908QY4, MC68HC908QT2, and MC68HC908QT4

• 5 or 13 bidirectional input/output (I/O) lines and one input only: – Six shared with keyboard interrupt function and ADC – Two shared with timer channels – One shared with external interrupt (IRQ) – Eight extra I/O lines on 16-pin package only – High current sink/source capability on all port pins – Selectable pullups on all ports, selectable on an individual bit basis – Three-state ability on all port pins

• 6-bit keyboard interrupt with wakeup feature (KBI)

• Low-voltage inhibit (LVI) module features: – Software selectable trip point in CONFIG register

• System protection features: – Computer operating properly (COP) watchdog – Low-voltage detection with reset – Illegal opcode detection with reset – Illegal address detection with reset

• External asynchronous interrupt pin with internal pullup (IRQ

) shared with general-purpose input

• Master asynchronous reset pin (RST

) shared with general-purpose input/output (I/O) pin

• Power-on reset

• Internal pullups on IRQ

and RST to reduce external components

• Memory mapped I/O registers

• Power saving stop and wait modes

• MC68HC908QY4, MC68HC908QY2, and MC68HC908QY1 are available in these packages: – 16-pin plastic dual in-line package (PDIP) – 16-pin small outline integrated circuit (SOIC) package – 16-pin thin shrink small outline package (TSSOP)

• MC68HC908QT4, MC68HC908QT2, and MC68HC908QT1 are available in these packages: – 8-pin PDIP – 8-pin SOIC – 8-pin dual flat no lead (DFN) package

MC68HC908QY/QT Family Data Sheet, Rev. 5

18 Freescale Semiconductor

MCU Block Diagram

Features of the CPU08 include the following:

• Enhanced HC05 programming model

• Extensive loop control functions

• 16 addressing modes (eight more than the HC05)

• 16-bit index register and stack pointer

• Memory-to-memory data transfers

• Fast 8 × 8 multiply instruction

• Fast 16/8 divide instruction

• Binary-coded decimal (BCD) instructions

• Optimization for controller applications

• Efficient C language support

1.3 MCU Block Diagram

Figure 1-1 shows the structure of the MC68HC908QY4.

1.4 Pin Assignments

The MC68HC908QT4, MC68HC908QT2, and MC68HC908QT1 are available in 8-pin packages and the MC68HC908QY4, MC68HC908QY2, and MC68HC908QY1 in 16-pin packages. Figure 1-2 shows the pin assignment for these packages.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 19

General Description

PTA0/AD0/TCH0/KBI0

PTA1/AD1/TCH1/KBI1

PTA2/IRQ

/KBI2/TCLK

PTA3/RST

PTA4/OSC2/AD2/KBI4

PTA5/OSC1/AD3/KBI5

/KBI3

PTB0 PTB1 PTB2 PTB3 PTB4 PTB5 PTB6 PTB7

POWER SUPPLY

PTA

PTB

8-BIT ADC

128 BYTES RAM

DDRA

DDRB

M68HC08 CPU

MC68HC908QY4 AND MC68HC908QT4

4096 BYTES

MC68HC908QY2, MC68HC908QY1,

MC68HC908QT2, AND MC68HC908QT1:

1536 BYTES

USER FLASH

CLOCK

GENERATOR

(OSCILLATOR)

SYSTEM INTEGRATION

MODULE

SINGLE INTERRUPT

MODULE

BREAK

MODULE

POWER-ON RESET

MODULE

KEYBOARD INTERRUPT

MODULE

16-BIT TIMER

MODULE

COP

MODULE

MONITOR ROM

RST, IRQ: Pins have internal (about 30K Ohms) pull up PTA[0:5]: High current sink and source capability PTA[0:5]: Pins have programmable keyboard interrupt and pull up PTB[0:7]: Not available on 8-pin devices – MC68HC908QT1, MC68HC908QT2, and MC68HC908QT4 (see note in

12.1 Introduction)

ADC: Not available on the MC68HC908QY1 and MC68HC908QT1

Figure 1-1. Block Diagram

MC68HC908QY/QT Family Data Sheet, Rev. 5

20 Freescale Semiconductor

Pin Assignments

PTA5/OSC1/KBI5

PTA4/OSC2/KBI4

PTA3/RST

/KBI3

PTB7

PTB6

PTA5/OSC1/KBI5

PTA4/OSC2/KBI4

PTB5

PTB4

PTA3/RST

/KBI3

8-PIN ASSIGNMENT

MC68HC908QT1 PDIP/SOIC

16-PIN ASSIGNMENT

MC68HC908QY1 PDIP/SOIC

PTA0/TCH0/KBI0

PTA1/TCH1/KBI1

PTA2/IRQ/KBI2/TCLK

PTB0

PTB1

PTA0/TCH0/KBI0

PTA1/TCH1/KBI1

PTB2

PTB3

PTA2/IRQ

/KBI2/TCLK

PTA5/OSC1/AD3/KBI5

PTA4/OSC2/AD2/KBI4

PTA3/RST

/KBI3

8-PIN ASSIGNMENT

MC68HC908QT2 AND MC68HC908QT4 PDIP/SOIC

PTB7

PTB6

PTA5/OSC1/AD3/KBI5

PTA4/OSC2/AD2/KBI4

PTB5

PTB4

PTA3/RST

/KBI3

16-PIN ASSIGNMENT

MC68HC908QY2 AND MC68HC908QY4 PDIP/SOIC

PTA0/AD0/TCH0/KBI0

PTA1/AD1/TCH1/KBI1

PTA2/IRQ/KBI2/TCLK

PTB0

PTB1

PTA0/AD0/TCH0/KBI0

PTA1/AD1/TCH1/KBI1

PTB2

PTB3

PTA2/IRQ

/KBI2/TCLK

PTA0/TCH0/KBI0

PTB1 PTB0

V V

PTB7 PTB6

PTA5/OSC1/KBI5

PTA0/TCH0/KBI0

PTA5/OSC1/KB15

1 2 3 4

6 7 8

16-PIN ASSIGNMENT

MC68HC908QY1 TSSOP

8-PIN ASSIGNMENT

MC68HC908QT1 DFN

PTA1/TCH1/KBI1

PTB2

PTB3

PTA2/IRQ

PTA3/RST

12 11

PTB4

PTB5

PTA4/OSC2/KBI4

PTA1/TCH1/KBI1

PTA2/IRQ/KBI2/TCLK

PTA3/RST

PTA4/OSC2/KBI4

/KBI2/TCLK

/KBI3

PTA0/AD0/TCH0/KBI0

PTA5/OSC1/AD3/KBI5

PTA0/AD0/TCH0/KBI0

PTA5//OSC1/AD3/KB15

Figure 1-2. MCU Pin Assignments

PTB1 PTB0

PTB7 PTB6

1 2 3 4

6 7 8

PTA1/AD1/TCH1/KBI1

PTB2

PTB3

PTA2/IRQ

PTA3/RST

12 11

PTB4

PTB5

PTA4/OSC2/AD2/KBI4

16-PIN ASSIGNMENT

MC68HC908QY2 AND MC68HC908QY4 TSSOP

PTA1/AD1/TCH1/KBI1

PTA2/IRQ/KBI2/TCLK

PTA3/RST

PTA4/OSC2/AD2/KBI4

8-PIN ASSIGNMENT

MC68HC908QT2 AND MC68HC908QT4 DFN

/KBI2/TCLK

/KBI3

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 21

General Description

1.5 Pin Functions

Table 1-2 provides a description of the pin functions.

Table 1-2. Pin Functions

Name

PTA0

PTA1

PTA2

PTA3

Description Input/Output

Power supply Power

Power supply ground Power

PTA0 — General purpose I/O port Input/Output

AD0 — A/D channel 0 input Input

TCH0 — Timer Channel 0 I/O Input/Output

KBI0 — Keyboard interrupt input 0 Input

PTA1 — General purpose I/O port Input/Output

AD1 — A/D channel 1 input Input

TCH1 — Timer Channel 1 I/O Input/Output

KBI1 — Keyboard interrupt input 1 Input

PTA2 — General purpose input-only port Input

— External interrupt with programmable pullup and Schmitt trigger input Input

IRQ

KBI2 — Keyboard interrupt input 2 Input

TCLK — Timer clock input Input

PTA3 — General purpose I/O port Input/Output

RST — Reset input, active low with internal pullup and Schmitt trigger Input

KBI3 — Keyboard interrupt input 3 Input

PTA4 — General purpose I/O port Input/Output

OSC2 —XTAL oscillator output (XTAL option only)

PTA4

PTA5

PTB[0:7]

1. The PTB pins are not available on the 8-pin packages (see note in 12.1 Introduction).

22 Freescale Semiconductor

RC or internal oscillator output (OSC2EN = 1 in PTAPUE register)

AD2 — A/D channel 2 input Input

KBI4 — Keyboard interrupt input 4 Input

PTA5 — General purpose I/O port Input/Output

OSC1 — XTAL, RC, or external oscillator input Input

AD3 — A/D channel 3 input Input

KBI5 — Keyboard interrupt input 5 Input

(1)

8 general-purpose I/O ports Input/Output

MC68HC908QY/QT Family Data Sheet, Rev. 5

Output Output

Pin Function Priority

1.6 Pin Function Priority

Table 1-3 is meant to resolve the priority if multiple functions are enabled on a single pin.

NOTE

Upon reset all pins come up as input ports regardless of the priority table.

Table 1-3. Function Priority in Shared Pins

Pin Name Highest-to-Lowest Priority Sequence

PTA0 AD0 → TCH0 → KBI0 → PTA0

PTA1 AD1 →TCH1 → KBI1 → PTA1

PTA2 IRQ

PTA3 RST

PTA4 OSC2 → AD2 → KBI4 → PTA4

PTA5 OSC1 → AD3 → KBI5 → PTA5

→ KBI2 → TCLK → PTA2

→ KBI3 → PTA3

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 23

General Description

MC68HC908QY/QT Family Data Sheet, Rev. 5

24 Freescale Semiconductor

Chapter 2 Memory

2.1 Introduction

The central processor unit (CPU08) can address 64 Kbytes of memory space. The memory map, shown in Figure 2-1, includes:

• 4096 bytes of user FLASH for MC68HC908QT4 and MC68HC908QY4

• 1536 bytes of user FLASH for MC68HC908QT2, MC68HC908QT1, MC68HC908QY2, and MC68HC908QY1

• 128 bytes of random access memory (RAM)

• 48 bytes of user-defined vectors, located in FLASH

• 416 bytes of monitor read-only memory (ROM)

• 1536 bytes of FLASH program and erase routines, located in ROM

2.2 Unimplemented Memory Locations

Accessing an unimplemented location can have unpredictable effects on MCU operation. In Figure 2-1 and in register figures in this document, unimplemented locations are shaded.

2.3 Reserved Memory Locations

Accessing a reserved location can have unpredictable effects on MCU operation. In Figure 2-1 and in register figures in this document, reserved locations are marked with the word Reserved or with the letter R.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 25

Memory

$0000

↓

$003F

$0040

↓

$007F

$0080

↓

$00FF

$0100

↓

$27FF

$2800

↓

$2DFF

$2E00

↓

$EDFF

$EE00

↓

$FDFF

$FE00 BREAK STATUS REGISTER (BSR)

$FE01 RESET STATUS REGISTER (SRSR)

$FE02 BREAK AUXILIARY REGISTER (BRKAR)

$FE03 BREAK FLAG CONTROL REGISTER (BFCR)

$FE04 INTERRUPT STATUS REGISTER 1 (INT1)

$FE05 INTERRUPT STATUS REGISTER 2 (INT2)

$FE06 INTERRUPT STATUS REGISTER 3 (INT3)

$FE07

$FE08

$FE09 BREAK ADDRESS HIGH REGISTER (BRKH)

$FE0A BREAK ADDRESS LOW REGISTER (BRKL)

$FE0B BREAK STATUS AND CONTROL REGISTER (BRKSCR)

$FE0C LVISR

$FE0D

↓

$FE0F

$FE10

↓

$FFAF

$FFB0

↓

$FFBD

$FFBE FLASH BLOCK PROTECT REGISTER (FLBPR)

$FFBF

$FFC0 INTERNAL OSCILLATOR TRIM VALUE

$FFC1

$FFC2

↓

$FFCF

$FFD0

↓

$FFFF

RESERVED FOR FLASH TEST CONTROL REGISTER (FLTCR)

MC68HC908QT4 AND MC68HC908QY4

FLASH CONTROL REGISTER (FLCR)

I/O REGISTERS

64 BYTES

RESERVED

64 BYTES

128 BYTES

UNIMPLEMENTED

9984 BYTES

AUXILIARY ROM

1536 BYTES

UNIMPLEMENTED

49152 BYTES

FLASH MEMORY

4096 BYTES

RESERVED FOR FLASH TEST

MONITOR ROM 416 BYTES

14 BYTES

RESERVED FLASH

14 BYTES

USER VECTORS

48 BYTES

(1)

RAM

(1)

3 BYTES

FLASH

Note 1.

Attempts to execute code from addresses in this range will generate an illegal address reset.

UNIMPLEMENTED

51712 BYTES

FLASH MEMORY

1536 BYTES

MC68HC908QT1, MC68HC908QT2,

MC68HC908QY1, and MC68HC908QY2

Memory Map

$2E00

↓

$F7FF

$F800

↓

$FDFF

Figure 2-1. Memory Map

MC68HC908QY/QT Family Data Sheet, Rev. 5

26 Freescale Semiconductor

Input/Output (I/O) Section

2.4 Input/Output (I/O) Section

Addresses $0000–$003F, shown in Figure 2-2, contain most of the control, status, and data registers. Additional I/O registers have these addresses:

• $FE00 — Break status register, BSR

• $FE01 — Reset status register, SRSR

• $FE02 — Break auxiliary register, BRKAR

• $FE03 — Break flag control register, BFCR

• $FE04 — Interrupt status register 1, INT1

• $FE05 — Interrupt status register 2, INT2

• $FE06 — Interrupt status register 3, INT3

•$FE07 — Reserved

• $FE08 — FLASH control register, FLCR

• $FE09 — Break address register high, BRKH

• $FE0A — Break address register low, BRKL

• $FE0B — Break status and control register, BRKSCR

• $FE0C — LVI status register, LVISR

•$FE0D — Reserved

• $FFBE — FLASH block protect register, FLBPR

• $FFC0 — Internal OSC trim value — Optional

• $FFFF — COP control register, COPCTL

Addr.Register Name Bit 7654321Bit 0

Port A Data Register

$0000

Port B Data Register

$0001

$0002 Unimplemented

$0003 Unimplemented

Data Direction Register A

$0004

Data Direction Register B

$0005

(PTA)

See page 98.

(PTB)

See page 100.

(DDRA)

See page 98.

(DDRB)

See page 101.

Read:

Write:

Reset: Unaffected by reset

Read:

Write:

Reset: Unaffected by reset

Read:

Write:

Reset:00000000

Read:

Write:

Reset:00000000

PTB7 PTB6 PTB5 PTB4 PTB3 PTB2 PTB1 PTB0

R R DDRA5 DDRA4 DDRA3

DDRB7 DDRB6 DDRB5 DDRB4 DDRB3 DDRB2 DDRB1 DDRB0

AWUL

= Unimplemented R = Reserved U = Unaffected

PTA5 PTA4 PTA3

PTA2

DDRA1 DDRA0

PTA1 PTA0

Figure 2-2. Control, Status, and Data Registers (Sheet 1 of 5)

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 27

Memory

Addr.Register Name Bit 7654321Bit 0

$0006

Unimplemented

↓

$000A

Unimplemented

Port A Input Pullup Enable

$000B

See page 99.

Port B Input Pullup Enable

$000C

See page 102.

$000D

↓

Unimplemented

$0019

Keyboard Status and

$001A

Control Register (KBSCR)

See page 83.

Keyboard Interrupt

$001B

Enable Register (KBIER)

See page 84.

$001C Unimplemented

IRQ Status and Control

$001D

See page 77.

Configuration Register 2

$001E

(CONFIG2)

See page 53.

Read:

Write:

OSC2EN

PTAPUE5 PTAPUE4 PTAPUE3 PTAPUE2 PTAPUE1 PTAPUE0

Reset:00000000

Read:

PTBPUE7 PTBPUE6 PTBPUE5 PTBPUE4 PTBPUE3 PTBPUE2 PTBPUE1 PTBPUE0

Write:

Reset:00000000

Read: 0 0 0 0 KEYF 0

Write: ACKK

IMASKK MODEK

Reset:00000000

Write:

AWUIE KBIE5 KBIE4 KBIE3 KBIE2 KBIE1 KBIE0

Reset:00000000

Read: 0 0 0 0 IRQF 0

Write: ACK

IMASK MODE

Reset:00000000

Read:

(1)

Reset:00000000

IRQPUD IRQEN R OSCOPT1 OSCOPT0 R R RSTEN

Write:

(2)

1. One-time writable register after each reset.

2. RSTEN reset to 0 by a power-on reset (POR) only.

Read:

(1)

Write:

COPRS LVISTOP LVIRSTD LVIPWRD LVI5OR3 SSREC STOP COPD

Reset:00000

(2)

000

$001F

Configuration Register 1

(CONFIG1)

See page 54.

1. One-time writable register after each reset.

2. LVI5OR3 reset to 0 by a power-on reset (POR) only.

$0020

$0021

TIM Status and Control

See page 127.

TIM Counter Register High

(TCNTH)

See page 128.

Read: TOF

Write: 0 TRST

TOIE TSTOP

Reset:00100000

Read: Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8

Write:

Reset:00000000

PS2 PS1 PS0

= Unimplemented R = Reserved U = Unaffected

Figure 2-2. Control, Status, and Data Registers (Sheet 2 of 5)

MC68HC908QY/QT Family Data Sheet, Rev. 5

28 Freescale Semiconductor

Input/Output (I/O) Section

Addr.Register Name Bit 7654321Bit 0

Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Write:

Reset:00000000

Read:

Write:

Reset:11111111

Read:

Write:

Reset:11111111

Read: CH0F

Write: 0

Reset:00000000

Read:

Write:

Reset: Indeterminate after reset

Read:

Write:

Reset: Indeterminate after reset

Read: CH1F

Write: 0

Reset:00000000

Read:

Write:

Reset: Indeterminate after reset

Read:

Write:

Reset: Indeterminate after reset

Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

CH0IE MS0B MS0A ELS0B ELS0A TOV0 CH0MAX

Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

CH1IE

Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

MS1A ELS1B ELS1A TOV1 CH1MAX

$0022

$0023

$0024

$0025

$0026

$0027

$0028

$0029

$002A

$002B

↓

$0035

TIM Counter Register Low

(TCNTL)

See page 128.

TIM Counter Modulo

See page 129.

TIM Counter Modulo

See page 129.

TIM Channel 0 Status and

Control Register (TSC0)

See page 130.

TIM Channel 0

See page 132.

TIM Channel 0

See page 132.

TIM Channel 1 Status and

Control Register (TSC1)

See page 130.

TIM Channel 1

See page 132.

TIM Channel 1

See page 132.

Unimplemented

Oscillator Status Register

$0036

$0037 Unimplemented Read:

Oscillator Trim Register

$0038

(OSCSTAT)

See page 96.

(OSCTRIM)

See page 96.

Read:

Write:

Reset:00000000

Read:

Write:

Reset:10000000

RRRRRRECGON

TRIM7 TRIM6 TRIM5 TRIM4 TRIM3 TRIM2 TRIM1 TRIM0

= Unimplemented R = Reserved U = Unaffected

ECGST

Figure 2-2. Control, Status, and Data Registers (Sheet 3 of 5)

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 29

Memory

Addr.Register Name Bit 7654321Bit 0

$0039

↓

$003B

Unimplemented

ADC Status and Control

$003C

$003D Unimplemented

$003E

$003F

$FE00

$FE01

$FE02

$FE03

$FE04

$FE05

$FE06

$FE07 Reserved RRRRRRRR

See page 45.

ADC Data Register

(ADR)

See page 47.

ADC Input Clock Register

(ADICLK)

See page 47.

Break Status Register

(BSR)

See page 137.

SIM Reset Status Register

(SRSR)

See page 117.

Break Auxiliary

See page 137.

Break Flag Control

See page 138.

Interrupt Status Register 1

(INT1)

See page 77.

Interrupt Status Register 2

(INT2)

See page 77.

Interrupt Status Register 3

(INT3)

See page 77.

Read: COCO

Write: R

Reset:00011111

Read:

Write:

Reset: Indeterminate after reset

Read:

Write:

Reset:00000000

Read:

Write: See note 1

Reset: 0

Read: POR PIN COP ILOP ILAD MODRST LVI 0

Write:

POR:10000000

Write:

Reset:00000000

Read:

Write:

Reset: 0

Read: 0 IF5 IF4 IF3 0 IF1 0 0

Write:RRRRRRRR

Reset:00000000

Read:IF140000000

Write:RRRRRRRR

Reset:00000000

Read:0000000IF15

Write:RRRRRRRR

Reset:00000000

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

ADIV2 ADIV1 ADIV0

RRRRRR

1. Writing a 0 clears SBSW.

BCFERRRRRRR

AIEN ADCO CH4 CH3 CH2 CH1 CH0

00000

SBSW

BDCOP

= Unimplemented R = Reserved U = Unaffected

Figure 2-2. Control, Status, and Data Registers (Sheet 4 of 5)

MC68HC908QY/QT Family Data Sheet, Rev. 5

30 Freescale Semiconductor

Input/Output (I/O) Section

Addr.Register Name Bit 7654321Bit 0

Write:

Reset:00000000

Read:

Write:

Reset:00000000

Read:

Write:

Reset:00000000

Read:

Write:

Reset:00000000

Read:LVIOUT000000R

Write:

Reset:00000000

Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

BRKE BRKA

000000

HVEN MASS ERASE PGM

$FE08

$FE09

$FE0A

$FE0B

$FE0C

$FE0D

↓

$FE0F

FLASH Control Register

(FLCR)

See page 33.

Break Address High

See page 136.

Break Address low

See page 136.

Break Status and Control

See page 136.

LVI Status Register

(LVISR)

See page 87.

Reserved for FLASH Test RRRRRRRR

FLASH Block Protect

$FFBE

$FFBF Reserved RRRRRRRR

$FFC0

$FFC1 Reserved RRRRRRRR

$FFFF

See page 38.

Internal Oscillator Trim

Value (Optional)

COP Control Register

(COPCTL)

See page 59.

Read:

Write:

Reset: Unaffected by reset

Read:

Write:

Reset: Unaffected by reset

Read: LOW BYTE OF RESET VECTOR

Write: WRITING CLEARS COP COUNTER (ANY VALUE)

Reset: Unaffected by reset

BPR7 BPR6 BPR5 BPR4 BPR3 BPR2 BPR1 BPR0

TRIM7 TRIM6 TRIM5 TRIM4 TRIM3 TRIM2 TRIM1 TRIM0

= Unimplemented R = Reserved U = Unaffected

Figure 2-2. Control, Status, and Data Registers (Sheet 5 of 5)

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 31

Memory

Table 2-1. Vector Addresses

Vector Priority Vector Address Vector

Lowest

Highest

IF15

IF14

IF13

↓

IF6

IF5

IF4

IF3

IF2 — Not used

IF1

—

$FFDE ADC conversion complete vector (high)

$FFDF ADC conversion complete vector (low)

$FFE0 Keyboard vector (high)

$FFE1 Keyboard vector (low)

— Not used

$FFF2 TIM overflow vector (high)

$FFF3 TIM overflow vector (low)

$FFF4 TIM Channel 1 vector (high)

$FFF5 TIM Channel 1 vector (low)

$FFF6 TIM Channel 0 vector (high)

$FFF7 TIM Channel 0 vector (low)

$FFFA IRQ

$FFFB IRQ

$FFFC SWI vector (high)

$FFFD SWI vector (low)

$FFFE Reset vector (high)

$FFFF Reset vector (low)

vector (high)

vector (low)

2.5 Random-Access Memory (RAM)

Addresses $0080–$00FF are RAM locations. The location of the stack RAM is programmable. The 16-bit stack pointer allows the stack to be anywhere in the 64-Kbyte memory space.

NOTE

For correct operation, the stack pointer must point only to RAM locations.

Before processing an interrupt, the central processor unit (CPU) uses five bytes of the stack to save the contents of the CPU registers.

NOTE

For M6805, M146805, and M68HC05 compatibility, the H register is not stacked.

During a subroutine call, the CPU uses two bytes of the stack to store the return address. The stack pointer decrements during pushes and increments during pulls.

NOTE

Be careful when using nested subroutines. The CPU may overwrite data in the RAM during a subroutine or during the interrupt stacking operation.

MC68HC908QY/QT Family Data Sheet, Rev. 5

32 Freescale Semiconductor

FLASH Memory (FLASH)

2.6 FLASH Memory (FLASH)

This subsection describes the operation of the embedded FLASH memory. The FLASH memory can be read, programmed, and erased from a single external supply. The program and erase operations are enabled through the use of an internal charge pump.

The FLASH memory consists of an array of 4096 or 1536 bytes with an additional 48 bytes for user vectors. The minimum size of FLASH memory that can be erased is 64 bytes; and the maximum size of FLASH memory that can be programmed in a program cycle is 32 bytes (a row). Program and erase operations are facilitated through control bits in the FLASH control register (FLCR). Details for these operations appear later in this section. The address ranges for the user memory and vectors are:

• $EE00 – $FDFF; user memory, 4096 bytes: MC68HC908QY4 and MC68HC908QT4

• $F800 – $FDFF; user memory, 1536 bytes: MC68HC908QY2, MC68HC908QT2, MC68HC908QY1 and MC68HC908QT1

• $FFD0 – $FFFF; user interrupt vectors, 48 bytes.

NOTE

An erased bit reads as a 1 and a programmed bit reads as a 0. A security feature prevents viewing of the FLASH contents.

2.6.1 FLASH Control Register

(1)

The FLASH control register (FLCR) controls FLASH program and erase operations.

Address: $FE08

Bit 7654321Bit 0

Write:

Reset:00000000

= Unimplemented

HVEN MASS ERASE PGM

Figure 2-3. FLASH Control Register (FLCR)

HVEN — High Voltage Enable Bit

This read/write bit enables high voltage from the charge pump to the memory for either program or erase operation. It can only be set if either PGM =1 or ERASE = 1 and the proper sequence for program or erase is followed.

1 = High voltage enabled to array and charge pump on 0 = High voltage disabled to array and charge pump off

MASS — Mass Erase Control Bit

This read/write bit configures the memory for mass erase operation.

1 = Mass erase operation selected 0 = Mass erase operation unselected

1. No security feature is absolutely secure. However, Freescale’s strategy is to make reading or copying the FLASH difficult for unauthorized users.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 33

Memory

ERASE — Erase Control Bit

This read/write bit configures the memory for erase operation. ERASE is interlocked with the PGM bit such that both bits cannot be equal to 1 or set to 1 at the same time.

1 = Erase operation selected 0 = Erase operation unselected

PGM — Program Control Bit

This read/write bit configures the memory for program operation. PGM is interlocked with the ERASE bit such that both bits cannot be equal to 1 or set to 1 at the same time.

1 = Program operation selected 0 = Program operation unselected

2.6.2 FLASH Page Erase Operation

Use the following procedure to erase a page of FLASH memory. A page consists of 64 consecutive bytes starting from addresses $XX00, $XX40, $XX80, or $XXC0. The 48-byte user interrupt vectors area also forms a page. Any FLASH memory page can be erased alone.

1. Set the ERASE bit and clear the MASS bit in the FLASH control register.

2. Read the FLASH block protect register.

3. Write any data to any FLASH location within the address range of the block to be erased.

4. Wait for a time, t

5. Set the HVEN bit.

6. Wait for a time, t

7. Clear the ERASE bit.

8. Wait for a time, t

9. Clear the HVEN bit.

10. After time, t

RCV

Programming and erasing of FLASH locations cannot be performed by code being executed from the FLASH memory. While these operations must be performed in the order as shown, but other unrelated operations may occur between the steps.

(minimum 10 µs).

NVS

(minimum 1 ms or 4 ms).

Erase

(minimum 5 µs).

NVH

(typical 1 µs), the memory can be accessed in read mode again.

NOTE

CAUTION A page erase of the vector page will erase the internal oscillator trim value at $FFC0.

In applications that require more than 1000 program/erase cycles, use the 4 ms page erase specification to get improved long-term reliability. Any application can use this 4 ms page erase specification. However, in applications where a FLASH location will be erased and reprogrammed less than 1000 times, and speed is important, use the 1 ms page erase specification to get a shorter cycle time.

MC68HC908QY/QT Family Data Sheet, Rev. 5

34 Freescale Semiconductor

2.6.3 FLASH Mass Erase Operation

Use the following procedure to erase the entire FLASH memory to read as a 1:

1. Set both the ERASE bit and the MASS bit in the FLASH control register.

2. Read the FLASH block protect register.

3. Write any data to any FLASH address

4. Wait for a time, t

(minimum 10 µs).

NVS

5. Set the HVEN bit.

6. Wait for a time, t

(minimum 4 ms).

MErase

7. Clear the ERASE and MASS bits.

Mass erase is disabled whenever any block is protected (FLBPR does not equal $FF).

(1)

within the FLASH memory address range.

NOTE

FLASH Memory (FLASH)

8. Wait for a time, t

(minimum 100 µs).

NVHL

9. Clear the HVEN bit.

10. After time, t

(typical 1 µs), the memory can be accessed in read mode again.

RCV

NOTE

CAUTION A mass erase will erase the internal oscillator trim value at $FFC0.

2.6.4 FLASH Program Operation

Programming of the FLASH memory is done on a row basis. A row consists of 32 consecutive bytes starting from addresses $XX00, $XX20, $XX40, $XX60, $XX80, $XXA0, $XXC0, or $XXE0. Use the following step-by-step procedure to program a row of FLASH memory

Figure 2-4 shows a flowchart of the programming algorithm.

NOTE

Only bytes which are currently $FF may be programmed.

1. Set the PGM bit. This configures the memory for program operation and enables the latching of address and data for programming.

2. Read the FLASH block protect register.

3. Write any data to any FLASH location within the address range desired.

4. Wait for a time, t

5. Set the HVEN bit.

6. Wait for a time, t

7. Write data to the FLASH address being programmed

(minimum 10 µs).

NVS

(minimum 5 µs).

PGS

(2)

1. When in monitor mode, with security sequence failed (see 15.3.2 Security), write to the FLASH block protect register instead of any FLASH address.

2. The time between each FLASH address change, or the time between the last FLASH address programmed to clearing PGM bit, must not exceed the maximum programming time, t

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 35

PROG

maximum.

Memory

8. Wait for time, t

(minimum 30 µs).

PROG

9. Repeat step 7 and 8 until all desired bytes within the row are programmed.

10. Clear the PGM bit

11. Wait for time, t

(1)

(minimum 5 µs).

NVH

12. Clear the HVEN bit.

13. After time, t

(typical 1 µs), the memory can be accessed in read mode again.

RCV

NOTE

The COP register at location $FFFF should not be written between steps 5–12, when the HVEN bit is set. Since this register is located at a valid FLASH address, unpredictable behavior may occur if this location is written while HVEN is set.

This program sequence is repeated throughout the memory until all data is programmed.

NOTE

Programming and erasing of FLASH locations cannot be performed by code being executed from the FLASH memory. While these operations must be performed in the order shown, other unrelated operations may occur between the steps. Do not exceed t

maximum, see 16.16

PROG

Memory Characteristics.

2.6.5 FLASH Protection

Due to the ability of the on-board charge pump to erase and program the FLASH memory in the target application, provision is made to protect blocks of memory from unintentional erase or program operations due to system malfunction. This protection is done by use of a FLASH block protect register (FLBPR). The FLBPR determines the range of the FLASH memory which is to be protected. The range of the protected area starts from a location defined by FLBPR and ends to the bottom of the FLASH memory ($FFFF). When the memory is protected, the HVEN bit cannot be set in either ERASE or PROGRAM operations.

NOTE

In performing a program or erase operation, the FLASH block protect register must be read after setting the PGM or ERASE bit and before asserting the HVEN bit.

When the FLBPR is programmed with all 0 s, the entire memory is protected from being programmed and erased. When all the bits are erased (all 1’s), the entire memory is accessible for program and erase.

When bits within the FLBPR are programmed, they lock a block of memory. The address ranges are shown in 2.6.6 FLASH Block Protect Register. Once the FLBPR is programmed with a value other than $FF, any erase or program of the FLBPR or the protected block of FLASH memory is prohibited. Mass erase is disabled whenever any block is protected (FLBPR does not equal $FF). The FLBPR itself can be erased or programmed only with an external voltage, V

, present on the IRQ pin. This voltage also

TST

allows entry from reset into the monitor mode.

MC68HC908QY/QT Family Data Sheet, Rev. 5

36 Freescale Semiconductor

FLASH Memory (FLASH)

Algorithm for Programming a Row (32 Bytes) of FLASH Memory

READ THE FLASH BLOCK PROTECT REGISTER

WRITE ANY DATA TO ANY FLASH ADDRESS

WITHIN THE ROW ADDRESS RANGE DESIRED

WRITE DATA TO THE FLASH ADDRESS

SET PGM BIT

WAIT FOR A TIME, t

SET HVEN BIT

WAIT FOR A TIME, t

TO BE PROGRAMMED

WAIT FOR A TIME, t

PROG

NVS

PGS

NOTES:

The time between each FLASH address change (step 7 to step 7), or the time between the last FLASH address programmed to clearing PGM bit (step 7 to step 10) must not exceed the maximum programming

PROG

max.

time, t

This row program algorithm assumes the row/s to be programmed are initially erased.

Figure 2-4. FLASH Programming Flowchart

COMPLETED

PROGRAMMING

THIS ROW?

CLEAR PGM BIT

WAIT FOR A TIME, t

CLEAR HVEN BIT

WAIT FOR A TIME, t

END OF PROGRAMMING

NVH

RCV

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 37

Memory

2.6.6 FLASH Block Protect Register

The FLASH block protect register is implemented as a byte within the FLASH memory, and therefore can only be written during a programming sequence of the FLASH memory. The value in this register determines the starting address of the protected range within the FLASH memory.

Address: $FFBE

Bit 7654321Bit 0

Read:

Write:

Reset: Unaffected by reset. Initial value from factory is 1.

Write to this register is by a programming sequence to the FLASH memory.

BPR[7:0] — FLASH Protection Register Bits [7:0]

These eight bits in FLBPR represent bits [13:6] of a 16-bit memory address. Bits [15:14] are 1s and bits [5:0] are 0s.

The resultant 16-bit address is used for specifying the start address of the FLASH memory for block protection. The FLASH is protected from this start address to the end of FLASH memory, at $FFFF. With this mechanism, the protect start address can be XX00, XX40, XX80, or XXC0 within the FLASH memory. See Figure 2-6 and Table 2-2.

BPR7 BPR6 BPR5 BPR4 BPR3 BPR2 BPR1 BPR0

Figure 2-5. FLASH Block Protect Register (FLBPR)

16-BIT MEMORY ADDRESS

START ADDRESS OF

FLASH BLOCK PROTECT

FLBPR VALUE

Figure 2-6. FLASH Block Protect Start Address

Table 2-2. Examples of Protect Start Address

BPR[7:0] Start of Address of Protect Range

$00–$B8 The entire FLASH memory is protected.

$B9 (1011 1001) $EE40 (1110 1110 0100 0000)

$BA (1011 1010) $EE80 (1110 1110 1000 0000)

$BB (1011 1011) $EEC0 (1110 1110 1100 0000)

$BC (1011 1100) $EF00 (1110 1111 0000 0000)

and so on...

$DE (1101 1110)$F780 (1111 0111 1000 0000)

$DF (1101 1111)$F7C0 (1111 0111 1100 0000)

$FE (1111 1110)

$FF The entire FLASH memory is not protected.

$FF80 (1111 1111 1000 0000)

FLBPR, OSCTRIM, and vectors are protected

00011

MC68HC908QY/QT Family Data Sheet, Rev. 5

38 Freescale Semiconductor

FLASH Memory (FLASH)

2.6.7 Wait Mode

Putting the MCU into wait mode while the FLASH is in read mode does not affect the operation of the FLASH memory directly, but there will not be any memory activity since the CPU is inactive.

The WAIT instruction should not be executed while performing a program or erase operation on the FLASH, or the operation will discontinue and the FLASH will be on standby mode.

2.6.8 Stop Mode

Putting the MCU into stop mode while the FLASH is in read mode does not affect the operation of the FLASH memory directly, but there will not be any memory activity since the CPU is inactive.

The STOP instruction should not be executed while performing a program or erase operation on the FLASH, or the operation will discontinue and the FLASH will be on standby mode

NOTE

Standby mode is the power-saving mode of the FLASH module in which all internal control signals to the FLASH are inactive and the current consumption of the FLASH is at a minimum.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 39

Memory

MC68HC908QY/QT Family Data Sheet, Rev. 5

40 Freescale Semiconductor

Chapter 3 Analog-to-Digital Converter (ADC)

3.1 Introduction

This section describes the analog-to-digital converter (ADC). The ADC is an 8-bit, 4-channel analog-todigital converter. The ADC module is only available on the MC68HC908QY2, MC68HC908QT2, MC68HC908QY4, and MC68HC908QT4.

3.2 Features

Features of the ADC module include:

• 4 channels with multiplexed input

• Linear successive approximation with monotonicity

• 8-bit resolution

• Single or continuous conversion

• Conversion complete flag or conversion complete interrupt

• Selectable ADC clock frequency

3.3 Functional Description

Four ADC channels are available for sampling external sources at pins PTA0, PTA1, PTA4, and PTA5. An analog multiplexer allows the single ADC converter to select one of the four ADC channels as an ADC voltage input (ADCVIN). ADCVIN is converted by the successive approximation register-based counters. The ADC resolution is eight bits. When the conversion is completed, ADC puts the result in the ADC data register and sets a flag or generates an interrupt.

Figure 3-2 shows a block diagram of the ADC.

3.3.1 ADC Port I/O Pins

PTA0, PTA1, PTA4, and PTA5 are general-purpose I/O pins that are shared with the ADC channels. The channel select bits (ADC status and control register (ADSCR), $003C), define which ADC channel/port pin will be used as the input signal. The ADC overrides the port I/O logic by forcing that pin as input to the ADC. The remaining ADC channels/port pins are controlled by the port I/O logic and can be used as general-purpose I/O. Writes to the port register or data direction register (DDR) will not have any affect on the port pin that is selected by the ADC. Read of a port pin which is in use by the ADC will return a 0 if the corresponding DDR bit is at 0. If the DDR bit is at 1, the value in the port data latch is read.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 41

Analog-to-Digital Converter (ADC)

PTA0/AD0/TCH0/KBI0

PTA1/AD1/TCH1/KBI1

PTA2/IRQ

/KBI2/TCLK

PTA3/RST

PTA4/OSC2/AD2/KBI4

PTA5/OSC1/AD3/KBI5

/KBI3

PTB0 PTB1 PTB2 PTB3 PTB4 PTB5 PTB6 PTB7

POWER SUPPLY

PTA

PTB

8-BIT ADC

128 BYTES RAM

DDRA

DDRB

M68HC08 CPU

MC68HC908QY4 AND MC68HC908QT4

4096 BYTES

MC68HC908QY2, MC68HC908QY1,

MC68HC908QT2, AND MC68HC908QT1:

1536 BYTES

USER FLASH

CLOCK

GENERATOR

(OSCILLATOR)

SYSTEM INTEGRATION

MODULE

SINGLE INTERRUPT

MODULE

BREAK

MODULE

POWER-ON RESET

MODULE

KEYBOARD INTERRUPT

MODULE

16-BIT TIMER

MODULE

COP

MODULE

MONITOR ROM

RST, IRQ: Pins have internal (about 30K Ohms) pull up

PTA[0:5]: High current sink and source capability PTA[0:5]: Pins have programmable keyboard interrupt and pull up

PTB[0:7]: Not available on 8-pin devices – MC68HC908QT1, MC68HC908QT2, and MC68HC908QT4 (see note in

12.1 Introduction)

ADC: Not available on the MC68HC908QY1 and MC68HC908QT1

Figure 3-1. Block Diagram Highlighting ADC Block and Pins

MC68HC908QY/QT Family Data Sheet, Rev. 5

42 Freescale Semiconductor

INTERNAL DATA BUS

Functional Description

READ DDRA

WRITE DDRA

WRITE PTA

READ PTA

INTERRUPT

LOGIC

AIEN COCO

CONVERSION COMPLETE

RESET

ADC DATA REGISTER

ADC

DDRAx

PTAx

ADC CLOCK

ADC VOLTAGE IN ADCVIN

DISABLE

ADC CHANNEL x

CHANNEL

SELECT

(1 OF 4 CHANNELS)

ADCx

CH[4:0]

BUS CLOCK

CLOCK

GENERATOR

ADIV[2:0]

Figure 3-2. ADC Block Diagram

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 43

Analog-to-Digital Converter (ADC)

3.3.2 Voltage Conversion

When the input voltage to the ADC equals VDD, the ADC converts the signal to $FF (full scale). If the input voltage equals V

the ADC converts it to $00. Input voltages between VDD and V

SS,

linear conversion. All other input voltages will result in $FF if greater than V

and $00 if less than VSS.

are a straight-line

NOTE

Input voltage should not exceed the analog supply voltages.

3.3.3 Conversion Time

Sixteen ADC internal clocks are required to perform one conversion. The ADC starts a conversion on the first rising edge of the ADC internal clock immediately following a write to the ADSCR. If the ADC internal clock is selected to run at 1 MHz, then one conversion will take 16 µs to complete. With a 1-MHz ADC internal clock the maximum sample rate is 62.5 kHz.

Conversion Time =

Number of Bus Cycles = Conversion Time × Bus Frequency

16 ADC Clock Cycles

ADC Clock Frequency

3.3.4 Continuous Conversion

In the continuous conversion mode (ADCO = 1), the ADC continuously converts the selected channel filling the ADC data register (ADR) with new data after each conversion. Data from the previous conversion will be overwritten whether that data has been read or not. Conversions will continue until the ADCO bit is cleared. The COCO bit (ADSCR, $003C) is set after each conversion and will stay set until the next read of the ADC data register.

When a conversion is in process and the ADSCR is written, the current conversion data should be discarded to prevent an incorrect reading.

3.3.5 Accuracy and Precision

The conversion process is monotonic and has no missing codes.

3.4 Interrupts

When the AIEN bit is set, the ADC module is capable of generating a central processor unit (CPU) interrupt after each ADC conversion. A CPU interrupt is generated if the COCO bit is at 0. The COCO bit is not used as a conversion complete flag when interrupts are enabled.

3.5 Low-Power Modes

The following subsections describe the ADC in low-power modes.

3.5.1 Wait Mode

The ADC continues normal operation during wait mode. Any enabled CPU interrupt request from the ADC can bring the microcontroller unit (MCU) out of wait mode. If the ADC is not required to bring the MCU out of wait mode, power down the ADC by setting the CH[4:0] bits in ADSCR to 1s before executing the WAIT instruction.

MC68HC908QY/QT Family Data Sheet, Rev. 5

44 Freescale Semiconductor

Input/Output Signals

3.5.2 Stop Mode

The ADC module is inactive after the execution of a STOP instruction. Any pending conversion is aborted. ADC conversions resume when the MCU exits stop mode. Allow one conversion cycle to stabilize the analog circuitry before using ADC data after exiting stop mode.

3.6 Input/Output Signals

The ADC module has four channels that are shared with I/O port A.

ADC voltage in (ADCVIN) is the input voltage signal from one of the four ADC channels to the ADC module.

3.7 Input/Output Registers

These I/O registers control and monitor ADC operation:

• ADC status and control register (ADSCR)

• ADC data register (ADR)

• ADC clock register (ADICLK)

3.7.1 ADC Status and Control Register

The following paragraphs describe the function of the ADC status and control register (ADSCR). When a conversion is in process and the ADSCR is written, the current conversion data should be discarded to prevent an incorrect reading.

Address: $003C

Bit 7654321Bit 0

Read: COCO

Write: R

Reset:00011111

R= Reserved

AIEN ADCO CH4 CH3 CH2 CH1 CH0

Figure 3-3. ADC Status and Control Register (ADSCR)

COCO — Conversions Complete Bit

In non-interrupt mode (AIEN = 0), COCO is a read-only bit that is set at the end of each conversion. COCO will stay set until cleared by a read of the ADC data register. Reset clears this bit.

In interrupt mode (AIEN = 1), COCO is a read-only bit that is not set at the end of a conversion. It always reads as a 0.

1 = Conversion completed (AIEN = 0) 0 = Conversion not completed (AIEN = 0) or CPU interrupt enabled (AIEN = 1)

NOTE

The write function of the COCO bit is reserved. When writing to the ADSCR register, always have a 0 in the COCO bit position.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 45

Analog-to-Digital Converter (ADC)

AIEN — ADC Interrupt Enable Bit

When this bit is set, an interrupt is generated at the end of an ADC conversion. The interrupt signal is cleared when ADR is read or ADSCR is written. Reset clears the AIEN bit.

1 = ADC interrupt enabled 0 = ADC interrupt disabled

ADCO — ADC Continuous Conversion Bit

When set, the ADC will convert samples continuously and update ADR at the end of each conversion. Only one conversion is allowed when this bit is cleared. Reset clears the ADCO bit.

1 = Continuous ADC conversion 0 = One ADC conversion

CH[4:0] — ADC Channel Select Bits

CH4, CH3, CH2, CH1, and CH0 form a 5-bit field which is used to select one of the four ADC channels. The five select bits are detailed in Table 3-1. Care should be taken when using a port pin as both an analog and a digital input simultaneously to prevent switching noise from corrupting the analog signal. The ADC subsystem is turned off when the channel select bits are all set to 1. This feature allows for reduced power consumption for the MCU when the ADC is not used. Reset sets all of these bits to 1.

NOTE

Recovery from the disabled state requires one conversion cycle to stabilize.

Table 3-1. MUX Channel Select

CH4 CH3 CH2 CH1 CH0

00000 ADC0 PTA0

00001 ADC1 PTA1

00010 ADC2 PTA4

00011 ADC3 PTA5

00100 — ↓↓↓↓↓ —

11010 —

11011 — Reserved

111 1 1—ADC power off

1. If any unused channels are selected, the resulting ADC conversion will be unknown.

2. The voltage levels supplied from internal reference nodes, as specified in the table, are used to verify the operation of the ADC converter both in production test and for user applications.

1 0 0 — Unused

1 0 1—

1 1 0—

ADC

Channel

Input Select

DDA

SSA

(1)

(2)

Unused

MC68HC908QY/QT Family Data Sheet, Rev. 5

46 Freescale Semiconductor

Input/Output Registers

3.7.2 ADC Data Register

One 8-bit result register is provided. This register is updated each time an ADC conversion completes.

Address: $003E

Bit 7654321Bit 0

Read: AD7 AD6 AD5 AD4 AD3 AD2 AD1 AD0

Write:

Reset: Indeterminate after reset

= Unimplemented

Figure 3-4. ADC Data Register (ADR)

3.7.3 ADC Input Clock Register

This register selects the clock frequency for the ADC.

Address: $003F

Bit 7654321Bit 0

Read:

Write:

Reset:00000000

ADIV2 ADIV1 ADIV0

= Unimplemented

00000

Figure 3-5. ADC Input Clock Register (ADICLK)

ADIV2–ADIV0 — ADC Clock Prescaler Bits

ADIV2, ADIV1, and ADIV0 form a 3-bit field which selects the divide ratio used by the ADC to generate the internal ADC clock. Table 3-2 shows the available clock configurations. The ADC clock frequency should be set between f

ADIC(MIN)

and f

ADIC(MAX)

. The analog input level should remain stable for the

entire conversion time (maximum = 17 ADC clock cycles).

Table 3-2. ADC Clock Divide Ratio

ADIV2 ADIV1 ADIV0 ADC Clock Rate

0 0 0 Bus clock ÷ 1

0 0 1 Bus clock ÷ 2

0 1 0 Bus clock ÷ 4

0 1 1 Bus clock ÷ 8

1 X X Bus clock ÷ 16

X = don’t care

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 47

Analog-to-Digital Converter (ADC)

MC68HC908QY/QT Family Data Sheet, Rev. 5

48 Freescale Semiconductor

Chapter 4 Auto Wakeup Module (AWU)

4.1 Introduction

This section describes the auto wakeup module (AWU). The AWU generates a periodic interrupt during stop mode to wake the part up without requiring an external signal. Figure 4-1 is a block diagram of the AWU.

4.2 Features

Features of the auto wakeup module include:

• One internal interrupt with separate interrupt enable bit, sharing the same keyboard interrupt vector and keyboard interrupt mask bit

• Exit from low-power stop mode without external signals

• Selectable timeout periods

• Dedicated low-power internal oscillator separate from the main system clock sources

4.3 Functional Description

The function of the auto wakeup logic is to generate periodic wakeup requests to bring the microcontroller unit (MCU) out of stop mode. The wakeup requests are treated as regular keyboard interrupt requests, with the difference that instead of a pin, the interrupt signal is generated by an internal logic.

Writing the AWUIE bit in the keyboard interrupt enable register enables or disables the auto wakeup interrupt input (see Figure 4-1). A logic 1 applied to the AWUIREQ input with auto wakeup interrupt request enabled, latches an auto wakeup interrupt request.

Auto wakeup latch, AWUL, can be read directly from the bit 6 position of port A data register (PTA). This is a read-only bit which is occupying an empty bit position on PTA. No PTA associated registers, such as PTA6 data direction or PTA6 pullup exist for this bit.

Entering stop mode will enable the auto wakeup generation logic. An internal RC oscillator (exclusive for the auto wakeup feature) drives the wakeup request generator. Once the overflow count is reached in the generator counter, a wakeup request, AWUIREQ, is latched and sent to the KBI logic. See Figure 4-1.

Wakeup interrupt requests will only be serviced if the associated interrupt enable bit, AWUIE, in KBIER is set. The AWU shares the keyboard interrupt vector.

The overflow count can be selected from two options defined by the COPRS bit in CONFIG1. This bit was “borrowed” from the computer operating properly (COP) using the fact that the COP feature is idle (no MCU clock available) in stop mode. The typical values of the periodic wakeup request are (at room temperature):

• COPRS = 0: 650 ms @ 5 V, 875 ms @ 3 V

• COPRS = 1: 16 ms @ 5 V, 22 ms @ 3 V

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 49

Auto Wakeup Module (AWU)

(CGMXCLK)

BUSCLKX4

RESET

COPRS (FROM CONFIG1)

INT RC OSC

EN 32 kHz

CLRLOGIC

CLEAR

CLK

RST

RESET

AUTOWUGE N

SHORT

CLK

AWUI E

1 = DIV 2 0 = DIV 2

OVERFLOW

RST

ISTOP

9 14

RESET

ACKK

Figure 4-1. Auto Wakeup Interrupt Request Generation Logic

TO PTA READ, BIT 6

AWUL

AWUIREQ

TO KBI INTERRUPT LOGIC (SEE

Figure 9-2. Keyboard Interrupt Block Diagram)

The auto wakeup RC oscillator is highly dependent on operating voltage and temperature. This feature is not recommended for use as a time-keeping function.

The wakeup request is latched to allow the interrupt source identification. The latched value, AWUL, can be read directly from the bit 6 position of PTA data register. This is a read-only bit which is occupying an empty bit position on PTA. No PTA associated registers, such as PTA6 data, PTA6 direction, and PTA6 pullup exist for this bit. The latch can be cleared by writing to the ACKK bit in the KBSCR register. Reset also clears the latch. AWUIE bit in KBI interrupt enable register (see Figure 4-1) has no effect on AWUL reading.

The AWU oscillator and counters are inactive in normal operating mode and become active only upon entering stop mode.

4.4 Wait Mode

The AWU module remains inactive in wait mode.

4.5 Stop Mode

When the AWU module is enabled (AWUIE = 1 in the keyboard interrupt enable register) it is activated automatically upon entering stop mode. Clearing the IMASKK bit in the keyboard status and control register enables keyboard interrupt requests to bring the MCU out of stop mode. The AWU counters start from ‘0’ each time stop mode is entered.

MC68HC908QY/QT Family Data Sheet, Rev. 5

50 Freescale Semiconductor

Input/Output Registers

4.6 Input/Output Registers

The AWU shares registers with the keyboard interrupt (KBI) module and the port A I/O module. The following I/O registers control and monitor operation of the AWU:

• Port A data register (PTA)

• Keyboard interrupt status and control register (KBSCR)

• Keyboard interrupt enable register (KBIER)

4.6.1 Port A I/O Register

The port A data register (PTA) contains a data latch for the state of the AWU interrupt request, in addition to the data latches for port A.

Address: $0000

Bit 7654321Bit 0

Read: 0 AWUL

Write:

Reset: 0 0 Unaffected by reset

= Unimplemented

PTA5 PTA4 PTA3

Figure 4-2. Port A Data Register (PTA)

PTA2

PTA1 PTA0

AWUL — Auto Wakeup Latch

This is a read-only bit which has the value of the auto wakeup interrupt request latch. The wakeup request signal is generated internally. There is no PTA6 port or any of the associated bits such as PTA6 data direction or pullup bits.

1 = Auto wakeup interrupt request is pending 0 = Auto wakeup interrupt request is not pending

NOTE

PTA5–PTA0 bits are not used in conjuction with the auto wakeup feature. To see a description of these bits, see 12.2.1 Port A Data Register.

4.6.2 Keyboard Status and Control Register

The keyboard status and control register (KBSCR):

• Flags keyboard/auto wakeup interrupt requests

• Acknowledges keyboard/auto wakeup interrupt requests

• Masks keyboard/auto wakeup interrupt requests

Address: $001A

Bit 7654321Bit 0

Read:0000KEYF0

Write: ACKK

Reset:00000000

= Unimplemented

IMASKK MODEK

Figure 4-3. Keyboard Status and Control Register (KBSCR)

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 51

Auto Wakeup Module (AWU)

Bits 7–4 — Not used

These read-only bits always read as 0s.

KEYF — Keyboard Flag Bit

This read-only bit is set when a keyboard interrupt is pending on port A or auto wakeup. Reset clears the KEYF bit.

1 = Keyboard/auto wakeup interrupt pending 0 = No keyboard/auto wakeup interrupt pending

ACKK — Keyboard Acknowledge Bit

Writing a 1 to this write-only bit clears the keyboard/auto wakeup interrupt request on port A and auto wakeup logic. ACKK always reads as 0.Reset clears ACKK.

IMASKK— Keyboard Interrupt Mask Bit

Writing a 1 to this read/write bit prevents the output of the keyboard interrupt mask from generating interrupt requests on port A or auto wakeup. Reset clears the IMASKK bit.

1 = Keyboard/auto wakeup interrupt requests masked 0 = Keyboard/auto wakeup interrupt requests not masked

NOTE

MODEK is not used in conjuction with the auto wakeup feature. To see a description of this bit, see 9.7.1 Keyboard Status and Control Register.

4.6.3 Keyboard Interrupt Enable Register

The keyboard interrupt enable register (KBIER) enables or disables the auto wakeup to operate as a keyboard/auto wakeup interrupt input.

Address: $001B

Bit 7654321Bit 0

Write:

Reset:00000000

Figure 4-4. Keyboard Interrupt Enable Register (KBIER)

AWUIE — Auto Wakeup Interrupt Enable Bit

This read/write bit enables the auto wakeup interrupt input to latch interrupt requests. Reset clears AWUIE.

1 = Auto wakeup enabled as interrupt input 0 = Auto wakeup not enabled as interrupt input

KBIE5–KBIE0 bits are not used in conjuction with the auto wakeup feature. To see a description of these bits, see 9.7.2 Keyboard Interrupt Enable

AWUIE KBIE5 KBIE4 KBIE3 KBIE2 KBIE1 KBIE0

= Unimplemented

NOTE

MC68HC908QY/QT Family Data Sheet, Rev. 5

52 Freescale Semiconductor

Chapter 5 Configuration Register (CONFIG)

5.1 Introduction

This section describes the configuration registers (CONFIG1 and CONFIG2). The configuration registers enable or disable the following options:

• Stop mode recovery time (32 × BUSCLKX4 cycles or 4096 × BUSCLKX4 cycles)

•STOP instruction

• Computer operating properly module (COP)

• COP reset period (COPRS): 8176 × BUSCLKX4 or 262,128 × BUSCLKX4

• Low-voltage inhibit (LVI) enable and trip voltage selection

• OSC option selection

•IRQ

•RST

• Auto wakeup timeout period

5.2 Functional Description

The configuration registers are used in the initialization of various options. The configuration registers can be written once after each reset. Most of the configuration register bits are cleared during reset. Since the various options affect the operation of the microcontroller unit (MCU) it is recommended that this register be written immediately after reset. The configuration registers are located at $001E and $001F, and may be read at anytime.

NOTE

The CONFIG registers are one-time writable by the user after each reset. Upon a reset, the CONFIG registers default to predetermined settings as shown in Figure 5-1 and Figure 5-2.

Address:

$001E

Bit 7654 321Bit 0

Read:

Write:

Reset:000 0 0 00U

IRQPUD IRQEN R OSCOPT1 OSCOPT0 R R RSTEN

POR:000 0 0 000

= Reserved U = Unaffected

Figure 5-1. Configuration Register 2 (CONFIG2)

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 53

Configuration Register (CONFIG)

IRQPUD — IRQ Pin Pullup Control Bit

1 = Internal pullup is disconnected 0 = Internal pullup is connected between IRQ

pin and V

IRQEN — IRQ Pin Function Selection Bit

1 = Interrupt request function active in pin 0 = Interrupt request function inactive in pin

OSCOPT1 and OSCOPT0 — Selection Bits for Oscillator Option

(0, 0) Internal oscillator (0, 1) External oscillator (1, 0) External RC oscillator (1, 1) External XTAL oscillator

RSTEN — RST

Pin Function Selection

1 = Reset function active in pin 0 = Reset function inactive in pin

NOTE

The RSTEN bit is cleared by a power-on reset (POR) only. Other resets will leave this bit unaffected.

Address:

$001F

Bit 7 6 5 4 3 2 1 Bit 0

Read:

Write:

Reset:0000U000

POR:00000000

COPRS LVISTOP LVIRSTD LVIPWRD LVI5OR3 SSREC STOP COPD

U = Unaffected

Figure 5-2. Configuration Register 1 (CONFIG1)

COPRS (Out of STOP Mode) — COP Reset Period Selection Bit

1 = COP reset short cycle = 8176 × BUSCLKX4 0 = COP reset long cycle = 262,128 × BUSCLKX4

COPRS (In STOP Mode) — Auto Wakeup Period Selection Bit

1 = Auto wakeup short cycle = 512 × INTRCOSC 0 = Auto wakeup long cycle = 16,384 × INTRCOSC

LVISTOP — LVI Enable in Stop Mode Bit

When the LVIPWRD bit is clear, setting the LVISTOP bit enables the LVI to operate during stop mode. Reset clears LVISTOP.

1 = LVI enabled during stop mode 0 = LVI disabled during stop mode

LVIRSTD — LVI Reset Disable Bit

LVIRSTD disables the reset signal from the LVI module.

1 = LVI module resets disabled 0 = LVI module resets enabled

MC68HC908QY/QT Family Data Sheet, Rev. 5

54 Freescale Semiconductor

Functional Description

LVIPWRD — LVI Power Disable Bit

LVIPWRD disables the LVI module.

1 = LVI module power disabled 0 = LVI module power enabled

LVI5OR3 — LVI 5-V or 3-V Operating Mode Bit

LVI5OR3 selects the voltage operating mode of the LVI module. The voltage mode selected for the LVI should match the operating V

for the LVI’s voltage trip points for each of the modes.

1 = LVI operates in 5-V mode 0 = LVI operates in 3-V mode

NOTE

The LVI5OR3 bit is cleared by a power-on reset (POR) only. Other resets will leave this bit unaffected.

SSREC — Short Stop Recovery Bit

SSREC enables the CPU to exit stop mode with a delay of 32 BUSCLKX4 cycles instead of a 4096 BUSCLKX4 cycle delay.

1 = Stop mode recovery after 32 BUSCLKX4 cycles 0 = Stop mode recovery after 4096 BUSCLKX4 cycles

NOTE

Exiting stop mode by an LVI reset will result in the long stop recovery.

The system stabilization time for power-on reset and long stop recovery (both 4096 BUSCLKX4 cycles) gives a delay longer than the LVI enable time for these startup scenarios. There is no period where the MCU is not protected from a low-power condition. However, when using the short stop recovery configuration option, the 32 BUSCLKX4 delay must be greater than the LVI’s turn on time to avoid a period in startup where the LVI is not protecting the MCU.

STOP — STOP Instruction Enable Bit

STOP enables the STOP instruction.

1 = STOP instruction enabled 0 = STOP instruction treated as illegal opcode

COPD — COP Disable Bit

COPD disables the COP module.

1 = COP module disabled 0 = COP module enabled

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 55

Configuration Register (CONFIG)

MC68HC908QY/QT Family Data Sheet, Rev. 5

56 Freescale Semiconductor

Chapter 6 Computer Operating Properly (COP)

6.1 Introduction

The computer operating properly (COP) module contains a free-running counter that generates a reset if allowed to overflow. The COP module helps software recover from runaway code. Prevent a COP reset by clearing the COP counter periodically. The COP module can be disabled through the COPD bit in the configuration 1 (CONFIG1) register.

6.2 Functional Description

BUSCLKX4

STOP INSTRUCTION

INTERNAL RESET SOURCES

COPCTL WRITE

COPEN (FROM SIM)

COP DISABLE (COPD FROM CONFIG1)

RESET

COPCTL WRITE

COP RATE SELECT

(COPRS FROM CONFIG1)

12-BIT SIM COUNTER

CLEAR ALL STAGES

COP CLOCK

CLEAR STAGES 5–12

6-BIT COP COUNTER

CLEAR

COP COUNTER

Figure 6-1. COP Block Diagram

RESET CIRCUIT

RESET STATUS REGISTER

COP TIMEOUT

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 57

Computer Operating Properly (COP)

The COP counter is a free-running 6-bit counter preceded by the 12-bit system integration module (SIM) counter. If not cleared by software, the COP counter overflows and generates an asynchronous reset after 262,128 or 8176 BUSCLKX4 cycles; depending on the state of the COP rate select bit, COPRS, in configuration register 1. With a 262,128 BUSCLKX4 cycle overflow option, the internal 12.8-MHz oscillator gives a COP timeout period of 20.48 ms. Writing any value to location $FFFF before an overflow occurs prevents a COP reset by clearing the COP counter and stages 12–5 of the SIM counter.

NOTE

Service the COP immediately after reset and before entering or after exiting stop mode to guarantee the maximum time before the first COP counter overflow.

A COP reset pulls the RST cycles and sets the COP bit in the reset status register (RSR). See 13.8.1 SIM Reset Status Register.

Place COP clearing instructions in the main program and not in an interrupt subroutine. Such an interrupt subroutine could keep the COP from generating a reset even while the main program is not working properly.

pin low (if the RSTEN bit is set in the CONFIG1 register) for 32 × BUSCLKX4

NOTE

6.3 I/O Signals

The following paragraphs describe the signals shown in Figure 6-1.

6.3.1 BUSCLKX4

BUSCLKX4 is the oscillator output signal. BUSCLKX4 frequency is equal to the internal oscillator frequency, the crystal frequency, or the RC-oscillator frequency.

6.3.2 STOP Instruction

The STOP instruction clears the SIM counter.

6.3.3 COPCTL Write

Writing any value to the COP control register (COPCTL) (see 6.4 COP Control Register) clears the COP counter and clears stages 12–5 of the SIM counter. Reading the COP control register returns the low byte of the reset vector.

6.3.4 Power-On Reset

The power-on reset (POR) circuit in the SIM clears the SIM counter 4096 × BUSCLKX4 cycles after power up.

6.3.5 Internal Reset

An internal reset clears the SIM counter and the COP counter.

6.3.6 COPD (COP Disable)

The COPD signal reflects the state of the COP disable bit (COPD) in the configuration register 1 (CONFIG1). See Chapter 5 Configuration Register (CONFIG).

MC68HC908QY/QT Family Data Sheet, Rev. 5

58 Freescale Semiconductor

COP Control Register

6.3.7 COPRS (COP Rate Select)

The COPRS signal reflects the state of the COP rate select bit (COPRS) in the configuration register 1 (CONFIG1). See Chapter 5 Configuration Register (CONFIG).

6.4 COP Control Register

The COP control register (COPCTL) is located at address $FFFF and overlaps the reset vector. Writing any value to $FFFF clears the COP counter and starts a new timeout period. Reading location $FFFF returns the low byte of the reset vector.

Address: $FFFF

Bit 7654321Bit 0

Read: LOW BYTE OF RESET VECTOR

Write: CLEAR COP COUNTER

Reset: Unaffected by reset

Figure 6-2. COP Control Register (COPCTL)

6.5 Interrupts

The COP does not generate CPU interrupt requests.

6.6 Monitor Mode

The COP is disabled in monitor mode when V

is present on the IRQ pin.

TST

6.7 Low-Power Modes

The WAIT and STOP instructions put the MCU in low power-consumption standby modes.

6.7.1 Wait Mode

The COP continues to operate during wait mode. To prevent a COP reset during wait mode, periodically clear the COP counter.

6.7.2 Stop Mode

Stop mode turns off the BUSCLKX4 input to the COP and clears the SIM counter. Service the COP immediately before entering or after exiting stop mode to ensure a full COP timeout period after entering or exiting stop mode.

6.8 COP Module During Break Mode

The COP is disabled during a break interrupt with monitor mode when BDCOP bit is set in break auxiliary register (BRKAR).

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 59

Computer Operating Properly (COP)

MC68HC908QY/QT Family Data Sheet, Rev. 5

60 Freescale Semiconductor

Chapter 7 Central Processor Unit (CPU)

7.1 Introduction

The M68HC08 CPU (central processor unit) is an enhanced and fully object-code-compatible version of the M68HC05 CPU. The CPU08 Reference Manual (document order number CPU08RM/AD) contains a description of the CPU instruction set, addressing modes, and architecture.

7.2 Features

Features of the CPU include:

• Object code fully upward-compatible with M68HC05 Family

• 16-bit stack pointer with stack manipulation instructions

• 16-bit index register with x-register manipulation instructions

• 8-MHz CPU internal bus frequency

• 64-Kbyte program/data memory space

• 16 addressing modes

• Memory-to-memory data moves without using accumulator

• Fast 8-bit by 8-bit multiply and 16-bit by 8-bit divide instructions

• Enhanced binary-coded decimal (BCD) data handling

• Modular architecture with expandable internal bus definition for extension of addressing range beyond 64 Kbytes

• Low-power stop and wait modes

7.3 CPU Registers

Figure 7-1 shows the five CPU registers. CPU registers are not part of the memory map.

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Freescale Semiconductor 61

Central Processor Unit (CPU)

H X

V11H I NZC

ACCUMULATOR (A)

INDEX REGISTER (H:X)

STACK POINTER (SP)

PROGRAM COUNTER (PC)

CONDITION CODE REGISTER (CCR)

CARRY/BORROW FLAG

ZERO FLAG

NEGATIVE FLAG

INTERRUPT MASK

HALF-CARRY FLAG

TWO’S COMPLEMENT OVERFLOW FLAG

Figure 7-1. CPU Registers

7.3.1 Accumulator

The accumulator is a general-purpose 8-bit register. The CPU uses the accumulator to hold operands and the results of arithmetic/logic operations.

Bit 7654321Bit 0

Read:

Write:

Reset: Unaffected by reset

Figure 7-2. Accumulator (A)

7.3.2 Index Register

The 16-bit index register allows indexed addressing of a 64-Kbyte memory space. H is the upper byte of the index register, and X is the lower byte. H:X is the concatenated 16-bit index register.

In the indexed addressing modes, the CPU uses the contents of the index register to determine the conditional address of the operand.

The index register can serve also as a temporary data storage location.

Bit 151413121110987654321

Read:

Write:

Reset:00000000XXXXXXXX

X = Indeterminate

Figure 7-3. Index Register (H:X)

Bit

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62 Freescale Semiconductor

CPU Registers

7.3.3 Stack Pointer

The stack pointer is a 16-bit register that contains the address of the next location on the stack. During a reset, the stack pointer is preset to $00FF. The reset stack pointer (RSP) instruction sets the least significant byte to $FF and does not affect the most significant byte. The stack pointer decrements as data is pushed onto the stack and increments as data is pulled from the stack.

In the stack pointer 8-bit offset and 16-bit offset addressing modes, the stack pointer can function as an index register to access data on the stack. The CPU uses the contents of the stack pointer to determine the conditional address of the operand.

Bit 151413121110987654321

Read:

Write:

Reset:0000000011111111

Bit

Figure 7-4. Stack Pointer (SP)

NOTE

The location of the stack is arbitrary and may be relocated anywhere in random-access memory (RAM). Moving the SP out of page 0 ($0000 to $00FF) frees direct address (page 0) space. For correct operation, the stack pointer must point only to RAM locations.

7.3.4 Program Counter

The program counter is a 16-bit register that contains the address of the next instruction or operand to be fetched.

Normally, the program counter automatically increments to the next sequential memory location every time an instruction or operand is fetched. Jump, branch, and interrupt operations load the program counter with an address other than that of the next sequential location.

During reset, the program counter is loaded with the reset vector address located at $FFFE and $FFFF. The vector address is the address of the first instruction to be executed after exiting the reset state.

Bit 151413121110987654321

Read:

Write:

Reset: Loaded with vector from $FFFE and $FFFF

Bit

Figure 7-5. Program Counter (PC)

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Freescale Semiconductor 63

Central Processor Unit (CPU)

7.3.5 Condition Code Register

The 8-bit condition code register contains the interrupt mask and five flags that indicate the results of the instruction just executed. Bits 6 and 5 are set permanently to 1. The following paragraphs describe the functions of the condition code register.

Bit 7654321Bit 0

Read:

Write:

Reset:X11X1XXX

V — Overflow Flag

The CPU sets the overflow flag when a two's complement overflow occurs. The signed branch instructions BGT, BGE, BLE, and BLT use the overflow flag.

1 = Overflow 0 = No overflow

H — Half-Carry Flag

The CPU sets the half-carry flag when a carry occurs between accumulator bits 3 and 4 during an add-without-carry (ADD) or add-with-carry (ADC) operation. The half-carry flag is required for binary-coded decimal (BCD) arithmetic operations. The DAA instruction uses the states of the H and C flags to determine the appropriate correction factor.

1 = Carry between bits 3 and 4 0 = No carry between bits 3 and 4

V11H I NZC

X = Indeterminate

Figure 7-6. Condition Code Register (CCR)

I — Interrupt Mask

When the interrupt mask is set, all maskable CPU interrupts are disabled. CPU interrupts are enabled when the interrupt mask is cleared. When a CPU interrupt occurs, the interrupt mask is set automatically after the CPU registers are saved on the stack, but before the interrupt vector is fetched.

1 = Interrupts disabled 0 = Interrupts enabled

NOTE

To maintain M6805 Family compatibility, the upper byte of the index register (H) is not stacked automatically. If the interrupt service routine modifies H, then the user must stack and unstack H using the PSHH and PULH instructions.

After the I bit is cleared, the highest-priority interrupt request is serviced first. A return-from-interrupt (RTI) instruction pulls the CPU registers from the stack and restores the interrupt mask from the stack. After any reset, the interrupt mask is set and can be cleared only by the clear interrupt mask software instruction (CLI).

N — Negative Flag

The CPU sets the negative flag when an arithmetic operation, logic operation, or data manipulation produces a negative result, setting bit 7 of the result.

1 = Negative result 0 = Non-negative result

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64 Freescale Semiconductor

Arithmetic/Logic Unit (ALU)

Z — Zero Flag

The CPU sets the zero flag when an arithmetic operation, logic operation, or data manipulation produces a result of $00.

1 = Zero result 0 = Non-zero result

C — Carry/Borrow Flag

The CPU sets the carry/borrow flag when an addition operation produces a carry out of bit 7 of the accumulator or when a subtraction operation requires a borrow. Some instructions — such as bit test and branch, shift, and rotate — also clear or set the carry/borrow flag.

1 = Carry out of bit 7 0 = No carry out of bit 7

7.4 Arithmetic/Logic Unit (ALU)

The ALU performs the arithmetic and logic operations defined by the instruction set.

Refer to the CPU08 Reference Manual (document order number CPU08RM/AD) for a description of the instructions and addressing modes and more detail about the architecture of the CPU.

7.5 Low-Power Modes

The WAIT and STOP instructions put the MCU in low power-consumption standby modes.

7.5.1 Wait Mode

The WAIT instruction:

• Clears the interrupt mask (I bit) in the condition code register, enabling interrupts. After exit from wait mode by interrupt, the I bit remains clear. After exit by reset, the I bit is set.

• Disables the CPU clock

7.5.2 Stop Mode

The STOP instruction:

• Clears the interrupt mask (I bit) in the condition code register, enabling external interrupts. After exit from stop mode by external interrupt, the I bit remains clear. After exit by reset, the I bit is set.

• Disables the CPU clock

After exiting stop mode, the CPU clock begins running after the oscillator stabilization delay.

7.6 CPU During Break Interrupts

If a break module is present on the MCU, the CPU starts a break interrupt by:

• Loading the instruction register with the SWI instruction

• Loading the program counter with $FFFC:$FFFD or with $FEFC:$FEFD in monitor mode

The break interrupt begins after completion of the CPU instruction in progress. If the break address register match occurs on the last cycle of a CPU instruction, the break interrupt begins immediately.

A return-from-interrupt instruction (RTI) in the break routine ends the break interrupt and returns the MCU to normal operation if the break interrupt has been deasserted.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 65

Central Processor Unit (CPU)

7.7 Instruction Set Summary

Table 7-1 provides a summary of the M68HC08 instruction set.

Table 7-1. Instruction Set Summary (Sheet 1 of 6)

Effect

Source

Form

ADC #opr ADC opr ADC opr ADC opr,X ADC opr,X ADC ,X ADC opr,SP ADC opr,SP

ADD #opr ADD opr ADD opr ADD opr,X ADD opr,X ADD ,X ADD opr,SP ADD opr,SP

AIS #

opr Add Immediate Value (Signed) to SP

AIX #opr Add Immediate Value (Signed) to H:X

AND #opr AND opr AND opr AND opr,X AND opr,X AND ,X AND opr,SP AND opr,SP

ASL opr ASLA ASLX ASL opr,X ASL ,X ASL opr,SP

ASR opr ASRA ASRX ASR opr,X ASR opr,X ASR opr,SP

BCC rel Branch if Carry Bit Clear PC ← (PC) + 2 + rel ? (C) = 0 ––––––REL 24 rr 3

BCLR n, opr Clear Bit n in M Mn ← 0 ––––––

BCS rel Branch if Carry Bit Set (Same as BLO) PC ← (PC) + 2 + rel ? (C) = 1 ––––––REL 25 rr 3 BEQ rel Branch if Equal PC ← (PC) + 2 + rel ? (Z) = 1 ––––––REL 27 rr 3

BGE opr

BGT opr

BHCC rel Branch if Half Carry Bit Clear PC ← (PC) + 2 + rel ? (H) = 0 ––––––REL 28 rr 3 BHCS rel Branch if Half Carry Bit Set PC ← (PC) + 2 + rel ? (H) = 1 ––––––REL 29 rr 3 BHI rel Branch if Higher PC ← (PC) + 2 + rel ? (C) | (Z) = 0 ––––––REL 22 rr 3

Add with Carry A ← (A) + (M) + (C) – 

Add without Carry A ← (A) + (M) – 

Logical AND A ← (A) & (M) 0 – – –

Arithmetic Shift Left (Same as LSL)

Arithmetic Shift Right  ––

Branch if Greater Than or Equal To (Signed Operands)

Branch if Greater Than (Signed Operands)

Operation Description

SP ← (SP) + (16

H:X ← (H:X) + (16

PC ← (PC) + 2 + rel ? (N

PC ← (PC) + 2 + rel ? (Z) | (N

« M)

⊕ V) = 0

on CCR

VH I NZC

––––––IMM A7 ii 2

––––––IMM AF ii 2

 ––



––––––REL 90 rr 3

––––––REL 92 rr 3

Address

Mode

IMM DIR EXT IX2 IX1 IX SP1 SP2

DIR INH INH IX1 IX SP1

DIR (b0) DIR (b1) DIR (b2) DIR (b3) DIR (b4) DIR (b5) DIR (b6) DIR (b7)

Opcode

B9 C9 D9

9EE9 9ED9

AB BB CB DB EB FB

9EEB 9EDB

B4 C4 D4

9EE4 9ED4

9E68

9E67

1B 1D

ii dd hh ll ee ff ff

ff ee ff

ii dd hh ll ee ff ff

ff ee ff

ii dd hh ll ee ff ff

ff ee ff

ff dd

dd dd dd dd dd dd dd dd

Operand

Cycles

2 3 4 4 3 2 4 5

4 1 1 4 3 5

4 4 4 4 4 4 4 4

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66 Freescale Semiconductor

Instruction Set Summary

Table 7-1. Instruction Set Summary (Sheet 2 of 6)

Effect

Source

Form

BHS rel

BIH rel Branch if IRQ BIL rel Branch if IRQ BIT #opr

BIT opr BIT opr BIT opr,X BIT opr,X BIT ,X BIT opr,SP BIT opr,SP

BLE opr

BLO rel Branch if Lower (Same as BCS) PC ← (PC) + 2 + rel ? (C) = 1 ––––––REL 25 rr 3 BLS rel Branch if Lower or Same PC ← (PC) + 2 + rel ? (C) | (Z) = 1 ––––––REL 23 rr 3

BLT opr Branch if Less Than (Signed Operands) BMC rel Branch if Interrupt Mask Clear PC ← (PC) + 2 + rel ? (I) = 0 ––––––REL 2C rr 3

BMI rel Branch if Minus PC ← (PC) + 2 + rel ? (N) = 1 ––––––REL 2B rr 3 BMS rel Branch if Interrupt Mask Set PC ← (PC) + 2 + rel ? (I) = 1 ––––––REL 2D rr 3 BNE rel Branch if Not Equal PC ← (PC) + 2 + rel ? (Z) = 0 ––––––REL 26 rr 3 BPL rel Branch if Plus PC ← (PC) + 2 + rel ? (N) = 0 ––––––REL 2A rr 3 BRA rel Branch Always PC ← (PC) + 2 + rel ––––––REL 20 rr 3

BRCLR n,opr,rel Branch if Bit n in M Clear PC ← (PC) + 3 + rel ? (Mn) = 0 –––––

BRN rel Branch Never PC ← (PC) + 2 ––––––REL 21 rr 3

BRSET n,opr,rel Branch if Bit n in M Set PC ← (PC) + 3 +

BSET n,opr Set Bit n in M Mn ← 1 ––––––

BSR rel Branch to Subroutine

CBEQ opr,rel CBEQA #opr,rel CBEQX #opr,rel CBEQ opr,X+,rel CBEQ X+,rel CBEQ opr,SP,rel

CLC Clear Carry Bit C ← 0 –––––0INH 98 1 CLI Clear Interrupt Mask I ← 0 ––0–––INH 9A 2

Branch if Higher or Same (Same as BCC)

Bit Test (A) & (M) 0 – – –

Branch if Less Than or Equal To (Signed Operands)

Compare and Branch if Equal

Operation Description

PC ← (PC) + 2 + rel ? (C) = 0 ––––––REL 24 rr 3

Pin High PC ← (PC) + 2 + rel ? IRQ = 1 ––––––REL 2F rr 3 Pin Low PC ← (PC) + 2 + rel ? IRQ = 0 ––––––REL 2E rr 3

PC ← (PC) + 2 + rel ? (Z) | (N

PC ← (PC) + 2 + rel ? (N

rel ? (Mn) = 1 –––––

PC ← (PC) + 2; push (PCL) SP ← (SP) – 1; push (PCH)

SP ← (SP) – 1

PC ← (PC) + rel

PC ← (PC) + 3 + rel ? (A) – (M) = $00 PC ← (PC) + 3 + rel ? (A) – (M) = $00 PC ← (PC) + 3 + rel ? (X) – (M) = $00 PC ← (PC) + 3 + rel ? (A) – (M) = $00 PC ← (PC) + 2 + rel ? (A) – (M) = $00 PC ← (PC) + 4 + rel ? (A) – (M) = $00

⊕ V) = 1

⊕ V) =1

on CCR

VH I NZC

––––––REL 93 rr 3

––––––REL 91 rr 3

––––––REL AD rr 4

––––––

Address

Mode

IMM DIR EXT IX2 IX1 IX SP1 SP2

DIR (b0) DIR (b1) DIR (b2) DIR (b3) DIR (b4) DIR (b5) DIR (b6) DIR (b7)

DIR IMM IMM IX1+ IX+ SP1

B5 C5 D5

9EE5 9ED5

0B 0D

0A 0C

1A 1C

9E61

Opcode

ii dd hh ll ee ff ff

ff ee ff

dd rr dd rr dd rr dd rr dd rr dd rr dd rr dd rr

dd dd dd dd dd dd dd dd

dd rr ii rr ii rr ff rr rr ff rr

Operand

2 3 4 4 3 2 4 5

5 5 5 5 5 5 5 5

4 4 4 4 4 4 4 4

5 4 4 5 4 6

Cycles

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 67

Central Processor Unit (CPU)

Source

Form

CLR opr CLRA CLRX CLRH CLR opr,X CLR ,X CLR opr,SP

CMP #opr CMP opr CMP opr CMP opr,X CMP opr,X CMP ,X CMP opr,SP CMP opr,SP

COM

opr

COMA COMX COM opr,X COM ,X COM opr,SP

CPHX #opr CPHX opr

CPX #opr CPX opr CPX opr CPX ,X CPX opr,X CPX opr,X CPX opr,SP CPX opr,SP

DAA Decimal Adjust A

DBNZ opr,rel DBNZA rel DBNZX rel DBNZ opr,X,rel DBNZ X,rel DBNZ opr,SP,rel

DEC opr DECA DECX DEC opr,X DEC ,X DEC opr,SP

DIV Divide

EOR #opr EOR opr EOR opr EOR opr,X EOR opr,X EOR ,X EOR opr,SP EOR opr,SP

INC opr INCA INCX INC opr,X INC ,X INC opr,SP

Clear

Compare A with M (A) – (M)  ––

Complement (One’s Complement)

Compare H:X with M (H:X) – (M:M + 1)  ––

Compare X with M (X) – (M)  ––

Decrement and Branch if Not Zero

Decrement

Exclusive OR M with A

Increment

Operation Description

Table 7-1. Instruction Set Summary (Sheet 3 of 6)

Effect

on CCR

VH I NZC

M ← $00 A ← $00 X ← $00 H ← $00 M ← $00 M ← $00 M ← $00

M ← (M

) = $FF – (M)

A ← (A

) = $FF – (M)

X ← (X) = $FF – (M)

M ← (M

) = $FF – (M)

M ← (M) = $FF – (M) M ← (M) = $FF – (M)

(A)

A ← (A) – 1 or M ← (M) – 1 or X ← (X) – 1

PC ← (PC) + 3 + rel ? (result) ≠ 0 PC ← (PC) + 2 + rel ? (result) ≠ 0 PC ← (PC) + 2 + rel ? (result) ≠ 0 PC ← (PC) + 3 + rel ? (result) ≠ 0 PC ← (PC) + 2 + rel ? (result) ≠ 0 PC ← (PC) + 4 + rel ? (result) ≠ 0

← (M) – 1 A ← (A) – 1 X ← (X) – 1

M ← (M) – 1 M ← (M) – 1 M ← (M) – 1

A ← (H:A)/(X)

H ← Remainder

A ← (A

⊕ M)

M ← (M) + 1

A ← (A) + 1 X ← (X) + 1

M ← (M) + 1 M ← (M) + 1 M ← (M) + 1

0––01–

0––1

U–– INH 72 2

––––––

 –––

––––INH 52 7

0–––

 –––

DIR INH INH INH IX1 IX SP1

IMM DIR EXT IX2 IX1 IX SP1 SP2

DIR INH INH IX1 IX SP1

IMM DIR

IMM DIR EXT IX2 IX1 IX SP1 SP2

DIR INH INH IX1 IX SP1

IMM DIR EXT IX2 IX1 IX SP1 SP2

DIR INH INH IX1 IX SP1

Address

Mode

Opcode

Operand

dd 4F 5F

ff 7F

9E6F

hh ll

ee ff

E1 F1

9EE1

ee ff

9ED1

dd 43 53 63

ff 73

9E63

ff 6575ii ii+1dd3

ii B3

hh ll

ee ff E3

ff F3

9EE3

9ED3

ee ff

dd rr 4B

rr 5B

rr 6B

ff rr 7B

9E6B

ff rr 3A

dd 4A 5A 6A

ff 7A

9E6A

ii B8

hh ll

ee ff E8

ff F8

9EE8

9ED8

ee ff

4C 5C 6C

9E6C

Cycles

3 1 1 1 3 2 4

2 3 4 4 3 2 4 5

4 1 1 4 3 5

4 2

3 4 4 3 2 4 5

5 3 3 5 4 6

4 1 1 4 3 5

2 3 4 4 3 2 4 5

4 1 1 4 3 5

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68 Freescale Semiconductor

Instruction Set Summary

Table 7-1. Instruction Set Summary (Sheet 4 of 6)

Effect

Source

Form

JMP opr JMP opr JMP opr,X JMP opr,X JMP ,X

JSR opr JSR opr JSR opr,X JSR opr,X JSR ,X

LDA #opr LDA opr LDA opr LDA opr,X LDA opr,X LDA ,X LDA opr,SP LDA opr,SP

LDHX #opr LDHX opr

LDX #opr LDX opr LDX opr LDX opr,X LDX opr,X LDX ,X LDX opr,SP LDX opr,SP

LSL opr LSLA LSLX LSL opr,X LSL ,X LSL opr,SP

LSR opr LSRA LSRX LSR opr,X LSR ,X LSR opr,SP

MOV opr,opr MOV opr,X+ MOV #opr,opr MOV X+,opr

MUL Unsigned multiply X:A ← (X) × (A) –0–––0INH 42 5 NEG opr

NEGA NEGX NEG opr,X NEG ,X NEG opr,SP

NOP No Operation None ––––––INH 9D 1 NSA Nibble Swap A A ← (A[3:0]:A[7:4]) ––––––INH 62 3 ORA #opr

ORA opr ORA opr ORA opr,X ORA opr,X ORA ,X ORA opr,SP ORA opr,SP

PSHA Push A onto Stack Push (A); SP ← (SP) – 1 ––––––INH 87 2 PSHH Push H onto Stack Push (H); SP ← (SP) – 1 ––––––INH 8B 2 PSHX Push X onto Stack Push (X); SP ← (SP) – 1 ––––––INH 89 2

Jump PC ← Jump Address ––––––

Jump to Subroutine

Load A from M A ← (M) 0–––

Load H:X from M H:X ← (M:M + 1) 0–––

Load X from M X ← (M) 0–––

Logical Shift Left (Same as ASL)

Logical Shift Right  ––0

Move

Negate (Two’s Complement)

Inclusive OR A and M A ← (A) | (M) 0 – – –

Operation Description

PC ← (PC) + n (n = 1, 2, or 3)

Push (PCL); SP ← (SP) – 1 Push (PCH); SP ← (SP) – 1

PC ← Unconditional Address

(M)

Destination

H:X ← (H:X) + 1 (IX+D, DIX+)

M ← –(M) = $00 – (M)

A ← –(A) = $00 – (A)

X ← –(X) = $00 – (X) M ← –(M) = $00 – (M) M ← –(M) = $00 – (M)

← (M)

Source

on CCR

VH I NZC

––––––

 ––

0–––

 ––

DIR EXT IX2 IX1 IX

IMM DIR EXT IX2 IX1 IX SP1 SP2

IMM DIR

IMM DIR EXT IX2 IX1 IX SP1 SP2

DIR INH INH IX1 IX SP1

DD DIX+ IMD IX+D

DIR INH INH IX1 IX SP1

IMM DIR EXT IX2 IX1 IX SP1 SP2

Address

Mode

Opcode

Operand

hh ll

ee ff

FC BD

hh ll

ee ff

hh ll

ee ff

9EE6

9ED6

ee ff

4555ii jjdd3

hh ll

ee ff

9EEE

9EDE

ee ff

dd 48 58 68

ff 78

9E68

ff 34

dd 44 54 64

ff 74

9E64

ff 4E

dd dd 5E

dd 6E

ii dd 7E

dd 40 50 60

ff 70

9E60

hh ll

ee ff

9EEA

ee ff

9EDA

2 3 4 3 2

4 5 6 5 4

2 3 4 4 3 2 4 5

4 2

3 4 4 3 2 4 5

4 1 1 4 3 5

5 4 4 4

4 1 1 4 3 5

2 3 4 4 3 2 4 5

Cycles

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 69

Central Processor Unit (CPU)

Table 7-1. Instruction Set Summary (Sheet 5 of 6)

Effect

Source

Form

PULA Pull A from Stack SP ← (SP + 1); Pull (A) ––––––INH 86 2 PULH Pull H from Stack SP ← (SP + 1); Pull (H) ––––––INH 8A 2 PULX Pull X from Stack SP ← (SP + 1); Pull (X) ––––––INH 88 2 ROL opr

ROLA ROLX ROL opr,X ROL ,X ROL opr,SP

ROR opr RORA RORX ROR opr,X ROR ,X ROR opr,SP

RSP Reset Stack Pointer SP ← $FF ––––––INH 9C 1

RTI Return from Interrupt

RTS Return from Subroutine

SBC #opr SBC opr SBC opr SBC opr,X SBC opr,X SBC ,X SBC opr,SP SBC opr,SP

SEC Set Carry Bit C ← 1 –––––1INH 99 1 SEI Set Interrupt Mask I ← 1 ––1–––INH 9B 2 STA opr

STA opr STA opr,X STA opr,X STA ,X STA opr,SP STA opr,SP

STHX opr Store H:X in M (M:M + 1) ← (H:X) 0 – – – DIR 35 dd 4

STOP

STX opr STX opr STX opr,X STX opr,X STX ,X STX opr,SP STX opr,SP

SUB #opr SUB opr SUB opr SUB opr,X SUB opr,X SUB ,X SUB opr,SP SUB opr,SP

Rotate Left through Carry  ––

Rotate Right through Carry  ––

Subtract with Carry A ← (A) – (M) – (C)  ––

Store A in M M ← (A) 0–––

Enable Interrupts, Stop Processing, Refer to MCU Documentation

Store X in M M ← (X) 0–––

Subtract A ← (A) – (M)  ––

Operation Description

SP ← (SP) + 1; Pull (CCR)

SP ← (SP) + 1; Pull (A) SP ← (SP) + 1; Pull (X)

SP ←

(SP) + 1; Pull (PCH)

SP ← (SP) + 1; Pull (PCL)

SP ← SP + 1; Pull (PCH) SP ← SP + 1; Pull (PCL)

I ← 0; Stop Processing ––0–––INH 8E 1

on CCR

VH I NZC

INH 80 7

––––––INH 81 4



DIR INH INH IX1 IX SP1

IMM DIR EXT IX2 IX1 IX SP1 SP2

DIR EXT IX2 IX1 IX SP1 SP2

IMM DIR EXT IX2 IX1 IX SP1 SP2

Address

Mode

9E69

9E66

9EE2 9ED2

9EE7 9ED7

9EEF 9EDF

9EE0 9ED0

39 49 59 69 79

36 46 56 66 76

A2 B2

C2 D2

E2 F2

C7 D7

E7 F7

BF CF DF EF

A0 B0

C0 D0

E0 F0

Opcode

hh ll

ee ff

hh ll

ee ff

hh ll

ee ff

hh ll

ee ff

Operand

Cycles

4 1 1 4 3 5

2 3 4 4 3 2 4 5

3 4 4 3 2 4 5

2 3 4 4 3 2 4 5

MC68HC908QY/QT Family Data Sheet, Rev. 5

70 Freescale Semiconductor

Opcode Map

Table 7-1. Instruction Set Summary (Sheet 6 of 6)

Effect

Source

Form

SWI Software Interrupt

TAP Transfer A to CCR CCR ← (A) INH 84 2 TAX Transfer A to X X ← (A) ––––––INH 97 1 TPA Transfer CCR to A A ← (CCR) ––––––INH 85 1 TST opr

TSTA TSTX TST opr,X TST ,X TST opr,SP

TSX Transfer SP to H:X H:X ← (SP) + 1 ––––––INH 95 2 TXA Transfer X to A A ← (X) ––––––INH 9F 1 TXS Transfer H:X to SP (SP) ← (H:X) – 1 ––––––INH 94 2

WAIT Enable Interrupts; Wait for Interrupt

A Accumulator n Any bit C Carry/borrow bit opr Operand (one or two bytes) CCR Condition code register PC Program counter dd Direct address of operand PCH Program counter high byte dd rr Direct address of operand and relative offset of branch instruction PCL Program counter low byte DD Direct to direct addressing mode REL Relative addressing mode DIR Direct addressing mode rel Relative program counter offset byte DIX+ Direct to indexed with post increment addressing mode rr Relative program counter offset byte ee ff High and low bytes of offset in indexed, 16-bit offset addressing SP1 Stack pointer, 8-bit offset addressing mode EXT Extended addressing mode SP2 Stack pointer 16-bit offset addressing mode ff Offset byte in indexed, 8-bit offset addressing SP Stack pointer H Half-carry bit U Undefined H Index register high byte V Overflow bit hh ll High and low bytes of operand address in extended addressing X Index register low byte I Interrupt mask Z Zero bit ii Immediate operand byte & Logical AND IMD Immediate source to direct destination addressing mode | Logical OR

IMM Immediate addressing mode INH Inherent addressing mode ( ) Contents of IX Indexed, no offset addressing mode –( ) Negation (two’s complement) IX+ Indexed, no offset, post increment addressing mode # Immediate value IX+D Indexed with post increment to direct addressing mode IX1 Indexed, 8-bit offset addressing mode ← Loaded with IX1+ Indexed, 8-bit offset, post increment addressing mode ? If IX2 Indexed, 16-bit offset addressing mode : Concatenated with M Memory location  Set or cleared N Negative bit — Not affected

Test for Negative or Zero (A) – $00 or (X) – $00 or (M) – $00 0 – – –

Operation Description

PC ← (PC) + 1; Push (PCL) SP ← (SP) – 1; Push (PCH)

SP ← (SP) – 1; Push (X) SP ← (SP) – 1; Push (A)

SP ← (SP) – 1; Push (CCR)

SP ← (SP) – 1; I ← 1

PCH ← Interrupt Vector High Byte

PCL ← Interrupt Vector Low Byte

I bit ← 0; Inhibit CPU clocking

until interrupted

⊕ Logical EXCLUSIVE OR

« Sign extend

on CCR

VH I NZC

––1–––INH 83 9

––0–––INH 8F 1

DIR INH INH IX1 IX SP1

Address

Mode

9E6D

3D 4D 5D 6D 7D

Opcode

Operand

3 1 1 3 2 4

Cycles

7.8 Opcode Map

See Table 7-2.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 71

Central Processor Unit (CPU)

SUB

1IX

SUB

3 SP1

SUB

2IX1

SUB

4 SP2

SUB

3IX2

SUB

3EXT

SUB

2DIR

SUB

2IMM

BGE

2REL

RTI

1INH

NEG

1IX

NEG

3 SP1

NEG

2IX1

NEGX

1INH

NEGA

1INH

NEG

2DIR

BRA

2REL

BSET0

2DIR

Table 7-2. Opcode Map

CMP

1IX

CMP

3 SP1

CMP

2IX1

CMP

4 SP2

CMP

3IX2

CMP

3EXT

CMP

2DIR

CMP

2IMM

BLT

2REL

RTS

1INH

CBEQ

2IX+

CBEQ

4 SP1

CBEQ

3IX1+

CBEQX

3IMM

CBEQA

3IMM

CBEQ

3DIR

BRN

2REL

BCLR0

2DIR

SBC

BGT

DAA

NSA

DIV

MUL

BHI

BSET1

1IX

3 SP1

2IX1

4 SP2

3IX2

3EXT

2DIR

2IMM

2REL

1INH

2REL

2DIR

CPX

BLE

SWI

COM

COMX

COMA

COM

BLS

BCLR1

1IX

3 SP1

2IX1

4 SP2

3IX2

3EXT

2DIR

2IMM

2REL

1INH

1IX

3 SP1

2IX1

1INH

2DIR

2REL

2DIR

AND

1IX

AND

3 SP1

AND

2IX1

AND

4 SP2

AND

3IX2

AND

3EXT

AND

2DIR

AND

2IMM

TXS

1INH

TA P

1INH

LSR

1IX

LSR

3 SP1

LSR

2IX1

LSRX

1INH

LSRA

1INH

LSR

2DIR

BCC

2REL

BSET2

2DIR

BIT

1IX

BIT

3 SP1

BIT

2IX1

BIT

4 SP2

BIT

3IX2

BIT

3EXT

BIT

2DIR

BIT

2IMM

TSX

1INH

TPA

1INH

CPHX

2DIR

CPHX

3IMM

LDHX

2DIR

LDHX

3IMM

STHX

2DIR

BCS

2REL

BCLR2

2DIR

LDA

1IX

LDA

3 SP1

LDA

2IX1

LDA

4 SP2

LDA

3IX2

LDA

3EXT

LDA

2DIR

LDA

2IMM

PULA

1INH

ROR

1IX

ROR

3 SP1

ROR

2IX1

RORX

1INH

RORA

1INH

ROR

2DIR

BNE

2REL

BSET3

2DIR

STA

1IX

STA

3 SP1

STA

2IX1

STA

4 SP2

STA

3IX2

STA

3EXT

STA

2DIR

AIS

2IMM

TA X

1INH

PSHA

1INH

ASR

1IX

ASR

3 SP1

ASR

2IX1

ASRX

1INH

ASRA

1INH

ASR

2DIR

BEQ

2REL

BCLR3

2DIR

EOR

1IX

EOR

3 SP1

EOR

2IX1

EOR

4 SP2

EOR

3IX2

EOR

3EXT

EOR

2DIR

EOR

2IMM

CLC

1INH

PULX

1INH

LSL

1IX

LSL

3 SP1

LSL

2IX1

LSLX

1INH

LSLA

1INH

LSL

2DIR

BHCC

2REL

BSET4

2DIR

ADC

SEC

PSHX

ROL

ROLX

ROLA

ROL

BHCS

BCLR4

1IX

3 SP1

2IX1

4 SP2

3IX2

3EXT

2DIR

2IMM

1INH

1IX

3 SP1

2IX1

1INH

2DIR

2REL

2DIR

ORA

1IX

ORA

3 SP1

ORA

2IX1

ORA

4 SP2

ORA

3IX2

ORA

3EXT

ORA

2DIR

ORA

2IMM

CLI

1INH

PULH

1INH

DEC

1IX

DEC

3 SP1

DEC

2IX1

DECX

1INH

DECA

1INH

DEC

2DIR

BPL

2REL

BSET5

2DIR

ADD

SEI

PSHH

DBNZ

DBNZX

DBNZA

DBNZ

BMI

BCLR5

1IX

3 SP1

2IX1

4 SP2

3IX2

3EXT

2DIR

2IMM

1INH

2IX

4 SP1

3IX1

2INH

3DIR

2REL

2DIR

JMP

1IX

JMP

2IX1

JMP

3IX2

JMP

3EXT

JMP

2DIR

RSP

1INH

CLRH

1INH

INC

1IX

INC

3 SP1

INC

2IX1

INCX

1INH

INCA

1INH

INC

2DIR

BMC

2REL

BSET6

2DIR

JSR

1IX

JSR

2IX1

JSR

3IX2

JSR

3EXT

JSR

2DIR

BSR

2REL

NOP

1INH

TST

1IX

TST

3 SP1

TST

2IX1

TSTX

1INH

TSTA

1INH

TST

2DIR

BMS

2REL

BCLR6

2DIR

STX

LDX

STOP

MOV

BIL

BSET7

1IX

3 SP1

2IX1

4 SP2

3IX2

3EXT

2DIR

2IMM

1INH

2IX+D

3IMD

2DIX+

3DD

2REL

2DIR

1IX

STX

3 SP1

STX

2IX1

STX

4 SP2

STX

3IX2

STX

3EXT

STX

2DIR

AIX

2IMM

TXA

1INH

WAIT

1INH

CLR

1IX

CLR

3 SP1

CLR

2IX1

CLRX

1INH

CLRA

1INH

CLR

2DIR

BIH

2REL

BCLR7

2DIR

MSB

0 High Byte of Opcode in Hexadecimal

LSB

Cycles

Opcode Mnemonic

Number of Bytes / Addressing Mode

BRSET0

3DIR

Low Byte of Opcode in Hexadecimal 0

BRCLR0

3DIR

BRSET1

3DIR

0 1 2 3 4 5 6 9E6 7 8 9 A B C D 9ED E 9EE F

DIR DIR REL DIR INH INH IX1 SP1 IX INH INH IMM DIR EXT IX2 SP2 IX1 SP1 IX

Bit Manipulation Branch Read-Modify-Write Control Register/Memory

MSB

BRSET0

3DIR

LSB

BRSET2

3DIR

BRCLR1

3DIR

BRSET3

3DIR

BRCLR2

3DIR

BRSET4

3DIR

BRCLR3

3DIR

BRSET5

3DIR

BRSET6

BRCLR5

3DIR

BRCLR6

3DIR

BRCLR4

3DIR

BRSET7

BRCLR7

3DIR

INH Inherent REL Relative SP1 Stack Pointer, 8-Bit Offset

IMM Immediate IX Indexed, No Offset SP2 Stack Pointer, 16-Bit Offset

DIR Direct IX1 Indexed, 8-Bit Offset IX+ Indexed, No Offset with

EXT Extended IX2 Indexed, 16-Bit Offset Post Increment

DD Direct-Direct IMD Immediate-Direct IX1+ Indexed, 1-Byte Offset with

IX+D Indexed-Direct DIX+ Direct-Indexed Post Increment

*Pre-byte for stack pointer indexed instructions

MC68HC908QY/QT Family Data Sheet, Rev. 5

72 Freescale Semiconductor

Chapter 8 External Interrupt (IRQ)

8.1 Introduction

The IRQ pin (external interrupt), shared with PTA2 (general purpose input) and keyboard interrupt (KBI), provides a maskable interrupt input

8.2 Features

Features of the IRQ module include the following:

• External interrupt pin, IRQ

•IRQ interrupt control bits

• Programmable edge-only or edge and level interrupt sensitivity

• Automatic interrupt acknowledge

• Selectable internal pullup resistor

8.3 Functional Description

IRQ pin functionality is enabled by setting configuration register 2 (CONFIG2) IRQEN bit accordingly. A zero disables the IRQ function and PTA2 will assume the other shared functionalities. A one enables the IRQ function.

A low level applied to the external interrupt request (IRQ

Figure 8-2 shows the structure of the IRQ module.

Interrupt signals on the IRQ following actions occurs:

• IRQ vector fetch — An IRQ vector fetch automatically generates an interrupt acknowledge signal that clears the IRQ latch.

• Software clear — Software can clear the IRQ latch by writing a 1 to the ACK bit in the interrupt status and control register (INTSCR).

• Reset — A reset automatically clears the IRQ latch.

The external interrupt pin is falling-edge-triggered out of reset and is software-configurable to be either falling-edge or falling-edge and low-level triggered. The MODE bit in INTSCR controls the triggering sensitivity of the IRQ

pin.

pin are latched into the IRQ latch. The IRQ latch remains set until one of the

) pin can latch a CPU interrupt request.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 73

External Interrupt (IRQ)

PTA0/AD0/TCH0/KBI0

PTA1/AD1/TCH1/KBI1

PTA2/IRQ

PTA4/OSC2/AD2/KBI4

PTA5/OSC1/AD3/KBI5

/KBI2/TCLK

PTA3/RST

/KBI3

PTB0 PTB1 PTB2 PTB3 PTB4 PTB5 PTB6 PTB7

POWER SUPPLY

PTA

PTB

8-BIT ADC

128 BYTES RAM

DDRA

DDRB

M68HC08 CPU

MC68HC908QY4 AND MC68HC908QT4

4096 BYTES

MC68HC908QY2, MC68HC908QY1,

MC68HC908QT2, AND MC68HC908QT1:

1536 BYTES

USER FLASH

CLOCK

GENERATOR

(OSCILLATOR)

SYSTEM INTEGRATION

MODULE

SINGLE INTERRUPT

MODULE

BREAK

MODULE

POWER-ON RESET

MODULE

KEYBOARD INTERRUPT

MODULE

16-BIT TIMER

MODULE

COP

MODULE

MONITOR ROM

RST, IRQ: Pins have internal (about 30K Ohms) pull up

PTA[0:5]: High current sink and source capability PTA[0:5]: Pins have programmable keyboard interrupt and pull up PTB[0:7]: Not available on 8-pin devices – MC68HC908QT1, MC68HC908QT2, and MC68HC908QT4 (see note in

12.1 Introduction)

ADC: Not available on the MC68HC908QY1 and MC68HC908QT1

Figure 8-1. Block Diagram Highlighting IRQ Block and Pins

When set, the IMASK bit in INTSCR masks the IRQ

interrupt request. A latched interrupt request is not

presented to the interrupt priority logic unless IMASK is clear.

NOTE

The interrupt mask (I) in the condition code register (CCR) masks all interrupt requests, including the IRQ

A falling edge on the IRQ

pin can latch an interrupt request into the IRQ latch. An IRQ vector fetch,

interrupt request.

software clear, or reset clears the IRQ latch.

MC68HC908QY/QT Family Data Sheet, Rev. 5

74 Freescale Semiconductor

INTERNAL ADDRESS BUS

IRQPUD

IRQ

ACK

RESET

VECTOR

FETCH

DECODER

INTERNAL PULLUP DEVICE

CLR

LATCH

MODE

IRQ

IMASK

SYNCHRO-

NIZER

HIGH

VOLTAGE

DETECT

Figure 8-2. IRQ Module Block Diagram

Functional Description

TO CPU FOR BIL/BIH INSTRUCTIONS

IRQF

IRQ INTERRUPT REQUEST

TO MODE SELECT LOGIC

8.3.1 MODE = 1

If the MODE bit is set, the IRQ pin is both falling edge sensitive and low level sensitive. With MODE set, both of the following actions must occur to clear the IRQ

• Return of the IRQ

pin to a high level. As long as the IRQ pin is low, the IRQ request remains active.

interrupt request:

• IRQ vector fetch or software clear. An IRQ vector fetch generates an interrupt acknowledge signal to clear the IRQ latch. Software generates the interrupt acknowledge signal by writing a 1 to ACK in INTSCR. The ACK bit is useful in applications that poll the IRQ

pin and require software to clear the IRQ latch. Writing to ACK prior to leaving an interrupt service routine can also prevent spurious interrupts due to noise. Setting ACK does not affect subsequent transitions on the IRQ

pin. A falling edge that occurs after writing to ACK latches another interrupt request. If the IRQ mask bit, IMASK, is clear, the CPU loads the program counter with the IRQ vector address.

The IRQ vector fetch or software clear and the return of the IRQ The interrupt request remains pending as long as the IRQ

pin to a high level may occur in any order.

pin is low. A reset will clear the IRQ latch and

the MODE control bit, thereby clearing the interrupt even if the pin stays low.

Use the BIH or BIL instruction to read the logic level on the IRQ

pin.

8.3.2 MODE = 0

If the MODE bit is clear, the IRQ pin is falling edge sensitive only. With MODE clear, an IRQ vector fetch or software clear immediately clears the IRQ latch.

The IRQF bit in INTSCR can be read to check for pending interrupts. The IRQF bit is not affected by IMASK, which makes it useful in applications where polling is preferred.

NOTE

When using the level-sensitive interrupt trigger, avoid false IRQ interrupts by masking interrupt requests in the interrupt routine.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 75

External Interrupt (IRQ)

8.4 Interrupts

The following IRQ source can generate interrupt requests:

• Interrupt flag (IRQF) — The IRQF bit is set when the IRQ The IRQ interrupt mask bit, IMASK, is used to enable or disable IRQ interrupt requests.

pin is asserted based on the IRQ mode.

8.5 Low-Power Modes

The WAIT and STOP instructions put the MCU in low power-consumption standby modes.

8.5.1 Wait Mode

The IRQ module remains active in wait mode. Clearing IMASK in INTSCR enables IRQ interrupt requests to bring the MCU out of wait mode.

8.5.2 Stop Mode

The IRQ module remains active in stop mode. Clearing IMASK in INTSCR enables IRQ interrupt requests to bring the MCU out of stop mode.

8.6 IRQ Module During Break Interrupts

The system integration module (SIM) controls whether status bits in other modules can be cleared during the break state. The BCFE bit in the break flag control register (BFCR) enables software to clear status bits during the break state. See Chapter 13 System Integration Module (SIM).

To allow software to clear status bits during a break interrupt, write a 1 to the BCFE bit. If a status bit is cleared during the break state, it remains cleared when the MCU exits the break state.

To protect status bits during the break state, write a 0 to BCFE. With BCFE cleared (its default state), software can read and write registers during the break state without affecting status bits. Some status bits have a two-step read/write clearing procedure. If software does the first step on such a bit before the break, the bit cannot change during the break state as long as BCFE is cleared. After the break, doing the second step clears the status bit.

8.7 I/O Signals

The IRQ module shares its pin with the keyboard interrupt, input/output ports, and timer interface modules.

NOTE

When the IRQ instructions can be used to read the logic level on the IRQ function is disabled, these instructions will behave as if the IRQ logic 1, regardless of the actual level on the pin. Conversely, when the IRQ function is enabled, bit 2 of the port A data register will always read a 0.

function is enabled in the CONFIG2 register, the BIH and BIL

pin. If the IRQ

pin is a

When using the level-sensitive interrupt trigger, avoid false interrupts by masking interrupt requests in the interrupt routine. An internal pullup resistor to V the IRQPUD bit in the CONFIG2 register ($001E).

76 Freescale Semiconductor

is connected to the IRQ pin; this can be disabled by setting

MC68HC908QY/QT Family Data Sheet, Rev. 5

Registers

8.7.1 IRQ Input Pins (IRQ)

The IRQ pin provides a maskable external interrupt source. The IRQ pin contains an internal pullup device.

8.8 Registers

The IRQ status and control register (INTSCR) controls and monitors operation of the IRQ module. See

Chapter 5 Configuration Register (CONFIG).

The INTSCR has the following functions:

• Shows the state of the IRQ flag

• Clears the IRQ latch

• Masks the IRQ interrupt request

• Controls triggering sensitivity of the IRQ

Address: $001D

Bit 7654321Bit 0

Read:0000IRQF0

Write: ACK

Reset:00000000

= Unimplemented

interrupt pin

IMASK MODE

Figure 8-3. IRQ Status and Control Register (INTSCR)

IRQF — IRQ Flag

This read-only status bit is set when the IRQ interrupt is pending.

1 = IRQ 0 = IRQ

interrupt pending interrupt not pending

ACK — IRQ Interrupt Request Acknowledge Bit

Writing a 1 to this write-only bit clears the IRQ latch. ACK always reads as 0.

IMASK — IRQ Interrupt Mask Bit

Writing a 1 to this read/write bit disables the IRQ interrupt request.

1 = IRQ interrupt request disabled 0 = IRQ interrupt request enabled

MODE — IRQ Edge/Level Select Bit

This read/write bit controls the triggering sensitivity of the IRQ

1 = IRQ 0 = IRQ

interrupt request on falling edges and low levels interrupt request on falling edges only

pin.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 77

External Interrupt (IRQ)

MC68HC908QY/QT Family Data Sheet, Rev. 5

78 Freescale Semiconductor

Chapter 9 Keyboard Interrupt Module (KBI)

9.1 Introduction

The keyboard interrupt module (KBI) provides six independently maskable external interrupts, which are accessible via the PTA0–PTA5 pins.

9.2 Features

Features of the keyboard interrupt module include:

• Six keyboard interrupt pins with separate keyboard interrupt enable bits and one keyboard interrupt mask

• Software configurable pullup device if input pin is configured as input port bit

• Programmable edge-only or edge and level interrupt sensitivity

• Exit from low-power modes

9.3 Functional Description

The keyboard interrupt module controls the enabling/disabling of interrupt functions on the six port A pins. These six pins can be enabled/disabled independently of each other. Refer to Figure 9-2.

9.3.1 Keyboard Operation

Writing to the KBIE0–KBIE5 bits in the keyboard interrupt enable register (KBIER) independently enables or disables each port A pin as a keyboard interrupt pin. Enabling a keyboard interrupt pin in port A also enables its internal pullup device irrespective of PTAPUEx bits in the port A input pullup enable register (see 12.2.3 Port A Input Pullup Enable Register). A logic 0 applied to an enabled keyboard interrupt pin latches a keyboard interrupt request.

A keyboard interrupt is latched when one or more keyboard interrupt inputs goes low after all were high. The MODEK bit in the keyboard status and control register controls the triggering mode of the keyboard interrupt.

• If the keyboard interrupt is edge-sensitive only, a falling edge on a keyboard interrupt input does not latch an interrupt request if another keyboard pin is already low. To prevent losing an interrupt request on one input because another input is still low, software can disable the latter input while it is low.

• If the keyboard interrupt is falling edge and low-level sensitive, an interrupt request is present as long as any keyboard interrupt input is low.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 79

Keyboard Interrupt Module (KBI)

PTA0/AD0/TCH0/KBI0

PTA1/AD1/TCH1/KBI1

PTA2/IRQ

/KBI2/TCLK

PTA3/RST

PTA4/OSC2/AD2/KBI4

PTA5/OSC1/AD3/KBI5

/KBI3

PTB0 PTB1 PTB2 PTB3 PTB4 PTB5 PTB6 PTB7

POWER SUPPLY

PTA

PTB

8-BIT ADC

128 BYTES RAM

DDRA

DDRB

M68HC08 CPU

MC68HC908QY4 AND MC68HC908QT4

4096 BYTES

MC68HC908QY2, MC68HC908QY1,

MC68HC908QT2, AND MC68HC908QT1:

1536 BYTES

USER FLASH

CLOCK

GENERATOR

(OSCILLATOR)

SYSTEM INTEGRATION

MODULE

SINGLE INTERRUPT

MODULE

BREAK

MODULE

POWER-ON RESET

MODULE

KEYBOARD INTERRUPT

MODULE

16-BIT TIMER

MODULE

COP

MODULE

MONITOR ROM

12.1 Introduction)

ADC: Not available on the MC68HC908QY1 and MC68HC908QT1

Figure 9-1. Block Diagram Highlighting KBI Block and Pins

MC68HC908QY/QT Family Data Sheet, Rev. 5

80 Freescale Semiconductor

KBI0

KBIE0

TO PULLUP ENABLE

KBI5

KBIE5

TO PULLUP ENABLE

Functional Description

INTERNAL BUS

VECTOR FETCH

DECODER

ACKK

CLR

KEYBOARD

INTERRUPT FF

MODEK

RESET

SYNCHRONIZER

IMASKK

KEYF

KEYBOARD INTERRUPT REQUEST

AWUIREQ

(1)

1. For AWUGEN logic refer to Figure 4-1. Auto Wakeup Interrupt Request Generation Logic.

Figure 9-2. Keyboard Interrupt Block Diagram

If the MODEK bit is set, the keyboard interrupt inputs are both falling edge and low-level sensitive, and both of the following actions must occur to clear a keyboard interrupt request:

• Vector fetch or software clear — A vector fetch generates an interrupt acknowledge signal to clear the interrupt request. Software may generate the interrupt acknowledge signal by writing a 1 to the ACKK bit in the keyboard status and control register (KBSCR). The ACKK bit is useful in applications that poll the keyboard interrupt inputs and require software to clear the keyboard interrupt request. Writing to the ACKK bit prior to leaving an interrupt service routine can also prevent spurious interrupts due to noise. Setting ACKK does not affect subsequent transitions on the keyboard interrupt inputs. A falling edge that occurs after writing to the ACKK bit latches another interrupt request. If the keyboard interrupt mask bit, IMASKK, is clear, the central processor unit (CPU) loads the program counter with the vector address at locations $FFE0 and $FFE1.

• Return of all enabled keyboard interrupt inputs to logic 1 — As long as any enabled keyboard interrupt pin is at logic 0, the keyboard interrupt remains set. The auto wakeup interrupt input, AWUIREQ, will be cleared only by writing to ACKK bit in KBSCR or reset.

The vector fetch or software clear and the return of all enabled keyboard interrupt pins to logic 1 may occur in any order.

If the MODEK bit is clear, the keyboard interrupt pin is falling-edge sensitive only. With MODEK clear, a vector fetch or software clear immediately clears the keyboard interrupt request.

Reset clears the keyboard interrupt request and the MODEK bit, clearing the interrupt request even if a keyboard interrupt input stays at logic 0.

The keyboard flag bit (KEYF) in the keyboard status and control register can be used to see if a pending interrupt exists. The KEYF bit is not affected by the keyboard interrupt mask bit (IMASKK) which makes it useful in applications where polling is preferred.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 81

Keyboard Interrupt Module (KBI)

To determine the logic level on a keyboard interrupt pin, use the data direction register to configure the pin as an input and then read the data register.

NOTE

Setting a keyboard interrupt enable bit (KBIEx) forces the corresponding keyboard interrupt pin to be an input, overriding the data direction register. However, the data direction register bit must be a 0 for software to read the pin.

9.3.2 Keyboard Initialization

When a keyboard interrupt pin is enabled, it takes time for the internal pullup to reach a logic 1. Therefore a false interrupt can occur as soon as the pin is enabled.

To prevent a false interrupt on keyboard initialization:

1. Mask keyboard interrupts by setting the IMASKK bit in the keyboard status and control register.

2. Enable the KBI pins by setting the appropriate KBIEx bits in the keyboard interrupt enable register.

3. Write to the ACKK bit in the keyboard status and control register to clear any false interrupts.

4. Clear the IMASKK bit.

An interrupt signal on an edge-triggered pin can be acknowledged immediately after enabling the pin. An interrupt signal on an edge- and level-triggered interrupt pin must be acknowledged after a delay that depends on the external load.

Another way to avoid a false interrupt:

1. Configure the keyboard pins as outputs by setting the appropriate DDRA bits in the data direction register A.

2. Write 1s to the appropriate port A data register bits.

3. Enable the KBI pins by setting the appropriate KBIEx bits in the keyboard interrupt enable register.

9.4 Wait Mode

The keyboard module remains active in wait mode. Clearing the IMASKK bit in the keyboard status and control register enables keyboard interrupt requests to bring the MCU out of wait mode.

9.5 Stop Mode

The keyboard module remains active in stop mode. Clearing the IMASKK bit in the keyboard status and control register enables keyboard interrupt requests to bring the MCU out of stop mode.

9.6 Keyboard Module During Break Interrupts

The system integration module (SIM) controls whether the keyboard interrupt latch can be cleared during the break state. The BCFE bit in the break flag control register (BFCR) enables software to clear status bits during the break state.

To allow software to clear the keyboard interrupt latch during a break interrupt, write a 1 to the BCFE bit. If a latch is cleared during the break state, it remains cleared when the MCU exits the break state.

MC68HC908QY/QT Family Data Sheet, Rev. 5

82 Freescale Semiconductor

Input/Output Registers

To protect the latch during the break state, write a 0 to the BCFE bit. With BCFE at 0 (its default state), writing to the keyboard acknowledge bit (ACKK) in the keyboard status and control register during the break state has no effect.

9.7 Input/Output Registers

The following I/O registers control and monitor operation of the keyboard interrupt module:

• Keyboard interrupt status and control register (KBSCR)

• Keyboard interrupt enable register (KBIER)

9.7.1 Keyboard Status and Control Register

The keyboard status and control register (KBSCR):

• Flags keyboard interrupt requests

• Acknowledges keyboard interrupt requests

• Masks keyboard interrupt requests

• Controls keyboard interrupt triggering sensitivity

Address: $001A

Bit 7654321Bit 0

Read:0000KEYF0

Write: ACKK

Reset:00000000

= Unimplemented

IMASKK MODEK

Figure 9-3. Keyboard Status and Control Register (KBSCR)

Bits 7–4 — Not used

These read-only bits always read as 0s.

KEYF — Keyboard Flag Bit

This read-only bit is set when a keyboard interrupt is pending on port A or auto wakeup. Reset clears the KEYF bit.

1 = Keyboard interrupt pending 0 = No keyboard interrupt pending

ACKK — Keyboard Acknowledge Bit

Writing a 1 to this write-only bit clears the keyboard interrupt request on port A and auto wakeup logic. ACKK always reads as 0. Reset clears ACKK.

IMASKK— Keyboard Interrupt Mask Bit

Writing a 1 to this read/write bit prevents the output of the keyboard interrupt mask from generating interrupt requests on port A or auto wakeup. Reset clears the IMASKK bit.

1 = Keyboard interrupt requests masked 0 = Keyboard interrupt requests not masked

MODEK — Keyboard Triggering Sensitivity Bit

This read/write bit controls the triggering sensitivity of the keyboard interrupt pins on port A and auto wakeup. Reset clears MODEK.

1 = Keyboard interrupt requests on falling edges and low levels 0 = Keyboard interrupt requests on falling edges only

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 83

Keyboard Interrupt Module (KBI)

9.7.2 Keyboard Interrupt Enable Register

The port A keyboard interrupt enable register (KBIER) enables or disables each port A pin or auto wakeup to operate as a keyboard interrupt input.

Address: $001B

Bit 7654321Bit 0

Write:

Reset:00000000

Figure 9-4. Keyboard Interrupt Enable Register (KBIER)

KBIE5–KBIE0 — Port A Keyboard Interrupt Enable Bits

Each of these read/write bits enables the corresponding keyboard interrupt pin on port A to latch interrupt requests. Reset clears the keyboard interrupt enable register.

1 = KBIx pin enabled as keyboard interrupt pin 0 = KBIx pin not enabled as keyboard interrupt pin

AWUIE bit is not used in conjunction with the keyboard interrupt feature. To see a description of this bit, see Chapter 4 Auto Wakeup Module (AWU).

AWUIE KBIE5 KBIE4 KBIE3 KBIE2 KBIE1 KBIE0

= Unimplemented

NOTE

MC68HC908QY/QT Family Data Sheet, Rev. 5

84 Freescale Semiconductor

Chapter 10 Low-Voltage Inhibit (LVI)

10.1 Introduction

This section describes the low-voltage inhibit (LVI) module, which monitors the voltage on the VDD pin and can force a reset when the V

10.2 Features

Features of the LVI module include:

• Programmable LVI reset

• Programmable power consumption

• Selectable LVI trip voltage

• Programmable stop mode operation

10.3 Functional Description

Figure 10-1 shows the structure of the LVI module. LVISTOP, LVIPWRD, LVI5OR3, and LVIRSTD are

user selectable options found in the configuration register (CONFIG1). See Chapter 5 Configuration

voltage falls below the LVI trip falling voltage, V

TRIPF

STOP INSTRUCTION

LVISTOP

FROM CONFIG

LVIRSTD

LVIPWRD

FROM CONFIG

LOW V

DETECTOR

LVI5OR3

FROM CONFIG

> LVITRIP = 0

≤ LVITRIP = 1

LVIOUT

LVI RESET

Figure 10-1. LVI Module Block Diagram

The LVI is enabled out of reset. The LVI module contains a bandgap reference circuit and comparator. Clearing the LVI power disable bit, LVIPWRD, enables the LVI to monitor V reset disable bit, LVIRSTD, enables the LVI module to generate a reset when V

MC68HC908QY/QT Family Data Sheet, Rev. 5

voltage. Clearing the LVI

falls below a voltage,

Freescale Semiconductor 85

Low-Voltage Inhibit (LVI)

V Setting the LVI 5-V or 3-V trip point bit, LVI5OR3, enables the trip point voltage, V for 5-V operation. Clearing the LVI5OR3 bit enables the trip point voltage, V

. Setting the LVI enable in stop mode bit, LVISTOP, enables the LVI to operate in stop mode.

TRIPF

, to be configured

TRIPF

, to be configured for 3-V

TRIPF

operation. The actual trip thresholds are specified in 16.5 5-V DC Electrical Characteristics and 16.9 3-V

DC Electrical Characteristics.

NOTE

After a power-on reset, the LVI’s default mode of operation is 3 volts. If a 5-V system is used, the user must set the LVI5OR3 bit to raise the trip point to 5-V operation.

If the user requires 5-V mode and sets the LVI5OR3 bit after power-on reset while the V

supply is not above the V

for 5-V mode, the

TRIPR

microcontroller unit (MCU) will immediately go into reset. The next time the LVI releases the reset, the supply will be above the V

Once an LVI reset occurs, the MCU remains in reset until V

rises above a voltage, V

for 5-V mode.

TRIPR

, which causes the MCU to exit reset. See Chapter 13 System Integration Module (SIM) for the reset recovery sequence.

The output of the comparator controls the state of the LVIOUT flag in the LVI status register (LVISR) and can be used for polling LVI operation when the LVI reset is disabled.

10.3.1 Polled LVI Operation

In applications that can operate at VDD levels below the V

level, software can monitor VDD by polling

TRIPF

the LVIOUT bit. In the configuration register, the LVIPWRD bit must be cleared to enable the LVI module, and the LVIRSTD bit must be at set to disable LVI resets.

10.3.2 Forced Reset Operation

In applications that require VDD to remain above the V module to reset the MCU when V

falls below the V

TRIPF

LVIPWRD and LVIRSTD bits must be cleared to enable the LVI module and to enable LVI resets.

level, enabling LVI resets allows the LVI

TRIPF

level. In the configuration register, the

10.3.3 Voltage Hysteresis Protection

Once the LVI has triggered (by having VDD fall below V V

rises above the rising trip point voltage, V

continually entering and exiting reset if V V

TRIPF

by the hysteresis voltage, V

HYS

is approximately equal to V

. This prevents a condition in which the MCU is

TRIPR

), the LVI will maintain a reset condition until

TRIPF

. V

is greater than

TRIPR

10.3.4 LVI Trip Selection

The LVI5OR3 bit in the configuration register selects whether the LVI is configured for 5-V or 3-V protection.

NOTE

The microcontroller is guaranteed to operate at a minimum supply voltage. The trip point (V See 16.5 5-V DC Electrical Characteristics and 16.9 3-V DC Electrical

Characteristics for the actual trip point voltages.

TRIPF

[5 V] or V

[3 V]) may be lower than this.

TRIPF

MC68HC908QY/QT Family Data Sheet, Rev. 5

86 Freescale Semiconductor

10.4 LVI Status Register

LVI Status Register

The LVI status register (LVISR) indicates if the VDD voltage was detected below the V LVI resets have been disabled

Address: $FE0C

Bit 7654321Bit 0

Read:LVIOUT000000R

Write:

Reset:00000000

= Unimplemented R = Reserved

TRIPF

Figure 10-2. LVI Status Register (LVISR)

LVIOUT — LVI Output Bit

This read-only flag becomes set when the V when V

voltage rises above V

. The difference in these threshold levels results in a hysteresis

TRIPR

voltage falls below the V

trip voltage and is cleared

TRIPF

that prevents oscillation into and out of reset (see Table 10-1). Reset clears the LVIOUT bit.

Table 10-1. LVIOUT Bit Indication

TRIPF

> V

VDD < V

< VDD < V

TRIPR

TRIPF

TRIPR

LVIOUT

Previous value

level while

10.5 LVI Interrupts

The LVI module does not generate interrupt requests.

10.6 Low-Power Modes

The STOP and WAIT instructions put the MCU in low power-consumption standby modes.

10.6.1 Wait Mode

If enabled, the LVI module remains active in wait mode. If enabled to generate resets, the LVI module can generate a reset and bring the MCU out of wait mode.

10.6.2 Stop Mode

When the LVIPWRD bit in the configuration register is cleared and the LVISTOP bit in the configuration register is set, the LVI module remains active in stop mode. If enabled to generate resets, the LVI module can generate a reset and bring the MCU out of stop mode.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 87

Low-Voltage Inhibit (LVI)

MC68HC908QY/QT Family Data Sheet, Rev. 5

88 Freescale Semiconductor

Chapter 11 Oscillator Module (OSC)

11.1 Introduction

The oscillator module is used to provide a stable clock source for the microcontroller system and bus. The oscillator module generates two output clocks, BUSCLKX2 and BUSCLKX4. The BUSCLKX4 clock is used by the system integration module (SIM) and the computer operating properly module (COP). The BUSCLKX2 clock is divided by two in the SIM to be used as the bus clock for the microcontroller. Therefore the bus frequency will be one fourth of the BUSCLKX4 frequency.

11.2 Features

The oscillator has these four clock source options available:

1. Internal oscillator: An internally generated, fixed frequency clock, trimmable to ±5%.This is the default option out of reset.

2. External oscillator: An external clock that can be driven directly into OSC1.

3. External RC: A built-in oscillator module (RC oscillator) that requires an external R connection only. The capacitor is internal to the chip.

4. External crystal: A built-in oscillator module (XTAL oscillator) that requires an external crystal or ceramic-resonator.

11.3 Functional Description

The oscillator contains these major subsystems:

• Internal oscillator circuit

• Internal or external clock switch control

• External clock circuit

• External crystal circuit

• External RC clock circuit

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 89

Oscillator Module (OSC)

PTA0/AD0/TCH0/KBI0

PTA1/AD1/TCH1/KBI1

PTA2/IRQ

/KBI2/TCLK

PTA3/RST

PTA4/OSC2/AD2/KBI4

PTA5/OSC1/AD3/KBI5

/KBI3

PTB0 PTB1 PTB2 PTB3 PTB4 PTB5 PTB6 PTB7

POWER SUPPLY

PTA

PTB

8-BIT ADC

128 BYTES RAM

DDRA

DDRB

M68HC08 CPU

MC68HC908QY4 AND MC68HC908QT4

4096 BYTES

MC68HC908QY2, MC68HC908QY1,

MC68HC908QT2, AND MC68HC908QT1:

1536 BYTES

USER FLASH

CLOCK

GENERATOR

(OSCILLATOR)

SYSTEM INTEGRATION

MODULE

SINGLE INTERRUPT

MODULE

BREAK

MODULE

POWER-ON RESET

MODULE

KEYBOARD INTERRUPT

MODULE

16-BIT TIMER

MODULE

COP

MODULE

MONITOR ROM

RST, IRQ: Pins have internal (about 30K Ohms) pull up

PTA[0:5]: High current sink and source capability PTA[0:5]: Pins have programmable keyboard interrupt and pull up

PTB[0:7]: Not available on 8-pin devices – MC68HC908QT1, MC68HC908QT2, and MC68HC908QT4 (see note in

12.1 Introduction)

ADC: Not available on the MC68HC908QY1 and MC68HC908QT1

Figure 11-1. Block Diagram Highlighting OSC Block and Pins

11.3.1 Internal Oscillator

The internal oscillator circuit is designed for use with no external components to provide a clock source with tolerance less than ±25% untrimmed.An 8-bit trimming register allows adjustment to a tolerance of less than ±5%.

The internal oscillator will generate a clock of 12.8 MHz typical (INTCLK) resulting in a bus speed (internal clock ÷ 4) of 3.2 MHz. 3.2 MHz came from the maximum bus speed guaranteed at 3 V which is 4 MHz.Since the internal oscillator will have a ±25% tolerance (pre-trim), then the +25% case should not allow a frequency higher than 4 MHz:

3.2 MHz + 25% = 4 MHz

Figure 11-3 shows how BUSCLKX4 is derived from INTCLK and, like the RC oscillator, OSC2 can output

BUSCLKX4 by setting OSC2EN in PTAPUE register. See Chapter 12 Input/Output Ports (PORTS)

MC68HC908QY/QT Family Data Sheet, Rev. 5

90 Freescale Semiconductor

Functional Description

11.3.1.1 Internal Oscillator Trimming

The 8-bit trimming register, OSCTRIM, allows a clock period adjust of +127 and –128 steps. Increasing OSCTRIM value increases the clock period. Trimming allows the internal clock frequency to be set to

12.8 MHz ± 5%.

All devices are programmed with a trim value in a reserved FLASH location, $FFC0. This value can be copied from the FLASH to the OSCTRIM register ($0038) during reset initialization.

Reset loads OSCTRIM with a default value of $80.

WARNING Bulk FLASH erasure will set location $FFC0 to $FF and the factory programmed value will be lost.

11.3.1.2 Internal to External Clock Switching

When external clock source (external OSC, RC, or XTAL) is desired, the user must perform the following steps:

1. For external crystal circuits only, OSCOPT[1:0] = 1:1: To help precharge an external crystal oscillator, set PTA4 (OSC2) as an output and drive high for several cycles. This may help the crystal circuit start more robustly.

2. Set CONFIG2 bits OSCOPT[1:0] according to . The oscillator module control logic will then set OSC1 as an external clock input and, if the external crystal option is selected, OSC2 will also be set as the clock output.

3. Create a software delay to wait the stabilization time needed for the selected clock source (crystal, resonator, RC) as recommended by the component manufacturer. A good rule of thumb for crystal oscillators is to wait 4096 cycles of the crystal frequency, i.e., for a 4-MHz crystal, wait approximately 1 msec.

4. After the manufacturer’s recommended delay has elapsed, the ECGON bit in the OSC status register (OSCSTAT) needs to be set by the user software.

5. After ECGON set is detected, the OSC module checks for oscillator activity by waiting two external clock rising edges.

6. The OSC module then switches to the external clock. Logic provides a glitch free transition.

7. The OSC module first sets the ECGST bit in the OSCSTAT register and then stops the internal oscillator.

NOTE

Once transition to the external clock is done, the internal oscillator will only be reactivated with reset. No post-switch clock monitor feature is implemented (clock does not switch back to internal if external clock dies).

11.3.2 External Oscillator

The external clock option is designed for use when a clock signal is available in the application to provide a clock source to the microcontroller. The OSC1 pin is enabled as an input by the oscillator module. The clock signal is used directly to create BUSCLKX4 and also divided by two to create BUSCLKX2.

In this configuration, the OSC2 pin cannot output BUSCLKX4.So the OSC2EN bit in the port A pullup enable register will be clear to enable PTA4 I/O functions on the pin

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 91

Oscillator Module (OSC)

11.3.3 XTAL Oscillator

The XTAL oscillator circuit is designed for use with an external crystal or ceramic resonator to provide an accurate clock source. In this configuration, the OSC2 pin is dedicated to the external crystal circuit. The OSC2EN bit in the port A pullup enable register has no effect when this clock mode is selected.

In its typical configuration, the XTAL oscillator is connected in a Pierce oscillator configuration, as shown in Figure 11-2. This figure shows only the logical representation of the internal components and may not represent actual circuitry. The oscillator configuration uses five components:

•Crystal, X

• Fixed capacitor, C

• Tuning capacitor, C2 (can also be a fixed capacitor)

• Feedback resistor, R

• Series resistor, RS (optional)

NOTE

The series resistor (R

) is included in the diagram to follow strict Pierce

oscillator guidelines and may not be required for all ranges of operation, especially with high frequency crystals. Refer to the crystal manufacturer’s data for more information.

FROM SIM

BUSCLKX2BUSCLKX4

XTALCLK

SIMOSCEN

MCU

OSC2OSC1

(1)

Note 1.

can be zero (shorted) when used with higher-frequency crystals. Refer to manufacturer’s

data. See Chapter 16 Electrical Specifications for component value recommendations.

TO SIMTO SIM

÷ 2

Figure 11-2. XTAL Oscillator External Connections

MC68HC908QY/QT Family Data Sheet, Rev. 5

92 Freescale Semiconductor

11.3.4 RC Oscillator

Oscillator Module Signals

The RC oscillator circuit is designed for use with an external resistor (R

) to provide a clock source with

EXT

a tolerance within 25% of the expected frequency. See Figure 11-3.

The capacitor (C) for the RC oscillator is internal to the MCU. The R 1%

or less to minimize its effect on the frequency.

value must have a tolerance of

EXT

In this configuration, the OSC2 pin can be left in the reset state as PTA4. Or, the OSC2EN bit in the port A pullup enable register can be set to enable the OSC2 output function on the pin. Enabling the OSC2 output slightly increases the external RC oscillator frequency, f

SIMOSCEN

MCU

EXTERNAL RC

OSCILLATOR

INTCLK

RCCLK

OSCRCOPT

TO SIM

PTA4

I/O

TO SIMFROM SIM

BUSCLKX2BUSCLKX4

÷ 2

PTA4

OSC2EN

OSC1

PTA4/BUSCLKX4 (OSC2)

EXT

See Chapter 16 Electrical Specifications for component value requirements.

Figure 11-3. RC Oscillator External Connections

11.4 Oscillator Module Signals

The following paragraphs describe the signals that are inputs to and outputs from the oscillator module.

11.4.1 Crystal Amplifier Input Pin (OSC1)

The OSC1 pin is either an input to the crystal oscillator amplifier, an input to the RC oscillator circuit, or an external clock source.

For the internal oscillator configuration, the OSC1 pin can assume other functions according to Table 1-3.

Function Priority in Shared Pins.

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 93

Oscillator Module (OSC)

11.4.2 Crystal Amplifier Output Pin (OSC2/PTA4/BUSCLKX4)

For the XTAL oscillator device, the OSC2 pin is the crystal oscillator inverting amplifier output.

For the external clock option, the OSC2 pin is dedicated to the PTA4 I/O function. The OSC2EN bit has no effect.

For the internal oscillator or RC oscillator options, the OSC2 pin can assume other functions according to

Table 1-3. Function Priority in Shared Pins, or the output of the oscillator clock (BUSCLKX4).

Table 11-1. OSC2 Pin Function

Option OSC2 Pin Function

XTAL oscillator Inverting OSC1

External clock PTA4 I/O

Internal oscillator

RC oscillator

Controlled by OSC2EN bit in PTAPUE register

OSC2EN = 0: PTA4 I/O

OSC2EN = 1: BUSCLKX4 output

11.4.3 Oscillator Enable Signal (SIMOSCEN)

The SIMOSCEN signal comes from the system integration module (SIM) and enables/disables either the XTAL oscillator circuit, the RC oscillator, or the internal oscillator.

11.4.4 XTAL Oscillator Clock (XTALCLK)

XTALCLK is the XTAL oscillator output signal. It runs at the full speed of the crystal (f directly from the crystal oscillator circuit. Figure 11-2 shows only the logical relation of XTALCLK to OSC1 and OSC2 and may not represent the actual circuitry. The duty cycle of XTALCLK is unknown and may depend on the crystal and other external factors. Also, the frequency and amplitude of XTALCLK can be unstable at start up.

) and comes

XCLK

11.4.5 RC Oscillator Clock (RCCLK)

RCCLK is the RC oscillator output signal. Its frequency is directly proportional to the time constant of external R and internal C. Figure 11-3 shows only the logical relation of RCCLK to OSC1 and may not represent the actual circuitry.

11.4.6 Internal Oscillator Clock (INTCLK)

INTCLK is the internal oscillator output signal. Its nominal frequency is fixed to 12.8 MHz, but it can be also trimmed using the oscillator trimming feature of the OSCTRIM register (see 11.3.1.1 Internal

Oscillator Trimming).

11.4.7 Oscillator Out 2 (BUSCLKX4)

BUSCLKX4 is the same as the input clock (XTALCLK, RCCLK, or INTCLK). This signal is driven to the SIM module and is used to determine the COP cycles.

11.4.8 Oscillator Out (BUSCLKX2)

The frequency of this signal is equal to half of the BUSCLKX4, this signal is driven to the SIM for generation of the bus clocks used by the CPU and other modules on the MCU. BUSCLKX2 will be divided

MC68HC908QY/QT Family Data Sheet, Rev. 5

94 Freescale Semiconductor

Low Power Modes

again in the SIM and results in the internal bus frequency being one fourth of either the XTALCLK, RCCLK, or INTCLK frequency.

11.5 Low Power Modes

The WAIT and STOP instructions put the MCU in low-power consumption standby modes.

11.5.1 Wait Mode

The WAIT instruction has no effect on the oscillator logic. BUSCLKX2 and BUSCLKX4 continue to drive to the SIM module.

11.5.2 Stop Mode

The STOP instruction disables either the XTALCLK, the RCCLK, or INTCLK output, hence BUSCLKX2 and BUSCLKX4.

11.6 Oscillator During Break Mode

The oscillator continues to drive BUSCLKX2 and BUSCLKX4 when the device enters the break state.

11.7 CONFIG2 Options

Two CONFIG2 register options affect the operation of the oscillator module: OSCOPT1 and OSCOPT0. All CONFIG2 register bits will have a default configuration. Refer to Chapter 5 Configuration Register

(CONFIG) for more information on how the CONFIG2 register is used.

Table 11-2 shows how the OSCOPT bits are used to select the oscillator clock source.

Table 11-2. Oscillator Modes

OSCOPT1 OSCOPT0 Oscillator Modes

0 0 Internal oscillator

0 1 External oscillator

10External RC

1 1 External crystal

11.8 Input/Output (I/O) Registers

The oscillator module contains these two registers:

1. Oscillator status register (OSCSTAT)

2. Oscillator trim register (OSCTRIM)

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 95

Oscillator Module (OSC)

11.8.1 Oscillator Status Register

The oscillator status register (OSCSTAT) contains the bits for switching from internal to external clock sources.

Address:

$0036

Bit 7654321Bit 0

Read:

Write:

Reset:00000000

RRRRRRECGON

=Reserved

= Unimplemented

ECGST

Figure 11-4. Oscillator Status Register (OSCSTAT)

ECGON — External Clock Generator On Bit

This read/write bit enables external clock generator, so that the switching process can be initiated. This bit is forced low during reset. This bit is ignored in monitor mode with the internal oscillator bypassed, PTM or CTM mode.

1 = External clock generator enabled 0 = External clock generator disabled

ECGST — External Clock Status Bit

This read-only bit indicates whether or not an external clock source is engaged to drive the system clock.

1 = An external clock source engaged 0 = An external clock source disengaged

11.8.2 Oscillator Trim Register (OSCTRIM)

Address:

$0038

Bit 7654321Bit 0

Read:

Write:

Reset:10000000

TRIM7 TRIM6 TRIM5 TRIM4 TRIM3 TRIM2 TRIM1 TRIM0

Figure 11-5. Oscillator Trim Register (OSCTRIM)

TRIM7–TRIM0 — Internal Oscillator Trim Factor Bits

These read/write bits change the size of the internal capacitor used by the internal oscillator. By measuring the period of the internal clock and adjusting this factor accordingly, the frequency of the internal clock can be fine tuned. Increasing (decreasing) this factor by one increases (decreases) the period by approximately 0.2% of the untrimmed period (the period for TRIM = $80). The trimmed frequency is guaranteed not to vary by more than ±5% over the full specified range of temperature and voltage. The reset value is $80, which sets the frequency to 12.8 MHz (3.2 MHz bus speed) ±25%.

MC68HC908QY/QT Family Data Sheet, Rev. 5

96 Freescale Semiconductor

Chapter 12 Input/Output Ports (PORTS)

12.1 Introduction

The MC68HC908QT1, MC68HC908QT2, and MC68HC908QT4 have five bidirectional input-output (I/O) pins and one input only pin. The MC68HC908QY1, MC68HC908QY2, and MC68HC908QY4 have thirteen bidirectional pins and one input only pin. All I/O pins are programmable as inputs or outputs.

NOTE

Connect any unused I/O pins to an appropriate logic level, either V Although the I/O ports do not require termination for proper operation, termination reduces excess current consumption and the possibility of electrostatic damage.

8-pin devices have non-bonded pins. These pins should be configured either as outputs driving low or high, or as inputs with internal pullups enabled. Configuring these non-bonded pins in this manner will prevent any excess current consumption caused by floating inputs.

12.2 Port A

or VSS.

Port A is a 6-bit special function port that shares all six of its pins with the keyboard interrupt (KBI) module (see Chapter 9 Keyboard Interrupt Module (KBI)). Each port A pin also has a software configurable pullup device if the corresponding port pin is configured as an input port.

NOTE

PTA2 is input only.

When the IRQ (CONFIG2), bit 2 of the port A data register (PTA) will always read a 0. In this case, the BIH and BIL instructions can be used to read the logic level on the PTA2 pin. When the IRQ behave as if the PTA2 pin is a logic 1. However, reading bit 2 of PTA will read the actual logic level on the pin.

function is enabled in the configuration register 2

function is disabled, these instructions will

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 97

Input/Output Ports (PORTS)

12.2.1 Port A Data Register

The port A data register (PTA) contains a data latch for each of the six port A pins.

Address:

Additional Functions:

$0000

Bit 76 5 4 3 2 1Bit 0

Read:

Write:

Reset: Unaffected by reset

R = Reserved

AWUL

PTA5 PTA4 PTA3

KBI5 KBI4 KBI3 KBI2 KBI1 KBI0

= Unimplemented

PTA2

PTA1 PTA0

Figure 12-1. Port A Data Register (PTA)

PTA[5:0] — Port A Data Bits

These read/write bits are software programmable. Data direction of each port A pin is under the control of the corresponding bit in data direction register A. Reset has no effect on port A data.

AWUL — Auto Wakeup Latch Data Bit

This is a read-only bit which has the value of the auto wakeup interrupt request latch. The wakeup request signal is generated internally (see Chapter 4 Auto Wakeup Module (AWU)). There is no PTA6 port nor any of the associated bits such as PTA6 data register, pullup enable or direction.

KBI[5:0] — Port A Keyboard Interrupts

The keyboard interrupt enable bits, KBIE5–KBIE0, in the keyboard interrupt control enable register (KBIER) enable the port A pins as external interrupt pins (see Chapter 9 Keyboard Interrupt Module

(KBI)).

12.2.2 Data Direction Register A

Data direction register A (DDRA) determines whether each port A pin is an input or an output. Writing a 1 to a DDRA bit enables the output buffer for the corresponding port A pin; a 0 disables the output buffer.

Address:

DDRA[5:0] — Data Direction Register A Bits

These read/write bits control port A data direction. Reset clears DDRA[5:0], configuring all port A pins as inputs.

1 = Corresponding port A pin configured as output 0 = Corresponding port A pin configured as input

Avoid glitches on port A pins by writing to the port A data register before changing data direction register A bits from 0 to 1.

$0004

Bit 7654321Bit 0

Read:

Write:

Reset:00000000

R R DDRA5 DDRA4 DDRA3

R= Reserved

= Unimplemented

DDRA1 DDRA0

Figure 12-2. Data Direction Register A (DDRA)

NOTE

MC68HC908QY/QT Family Data Sheet, Rev. 5

98 Freescale Semiconductor

Figure 12-3 shows the port A I/O logic.

READ DDRA ($0004)

WRITE DDRA ($0004)

RESET

Port A

PTAPUEx

DDRAx

30 k

WRITE PTA ($0000)

PTAx

INTERNAL DATA BUS

READ PTA ($0000)

TO KEYBOARD INTERRUPT CIRCUIT

PTAx

Figure 12-3. Port A I/O Circuit

NOTE

Figure 12-3 does not apply to PTA2

When DDRAx is a 1, reading address $0000 reads the PTAx data latch. When DDRAx is a 0, reading address $0000 reads the voltage level on the pin. The data latch can always be written, regardless of the state of its data direction bit.

12.2.3 Port A Input Pullup Enable Register

The port A input pullup enable register (PTAPUE) contains a software configurable pullup device for each if the six port A pins. Each bit is individually configurable and requires the corresponding data direction register, DDRAx, to be configured as input. Each pullup device is automatically and dynamically disabled when its corresponding DDRAx bit is configured as output.

Address:

$000B

Bit 7654321Bit 0

Read:

OSC2EN PTAPUE5 PTAPUE4 PTAPUE3 PTAPUE2 PTAPUE1 PTAPUE0

Write:

Reset:00000000

= Unimplemented

Figure 12-4. Port A Input Pullup Enable Register (PTAPUE)

OSC2EN — Enable PTA4 on OSC2 Pin

This read/write bit configures the OSC2 pin function when internal oscillator or RC oscillator option is selected. This bit has no effect for the XTAL or external oscillator options.

1 = OSC2 pin outputs the internal or RC oscillator clock (BUSCLKX4) 0 = OSC2 pin configured for PTA4 I/O, having all the interrupt and pullup functions

MC68HC908QY/QT Family Data Sheet, Rev. 5

Freescale Semiconductor 99

Input/Output Ports (PORTS)

PTAPUE[5:0] — Port A Input Pullup Enable Bits

These read/write bits are software programmable to enable pullup devices on port A pins.

1 = Corresponding port A pin configured to have internal pull if its DDRA bit is set to 0 0 = Pullup device is disconnected on the corresponding port A pin regardless of the state of its

DDRA bit

Table 12-1 summarizes the operation of the port A pins.

Table 12-1. Port A Pin Functions

PTAPUE

Bit

00X

X 1 X Output DDRA5–DDRA0 PTA5–PTA0

1. X = don’t care

2. I/O pin pulled to VDD by internal pullup.

3. Writing affects data register, but does not affect input.

4. Hi-Z = high impedance

5. Output does not apply to PTA2

DDRA

Bit

PTA

Bit

(1)

I/O Pin

Mode

Input, V

Input, Hi-Z

(2)

(4)

Accesses to DDRA Accesses to PTA

Read/Write Read Write

DDRA5–DDRA0 Pin

PTA5–PTA0

12.3 Port B

Port B is an 8-bit general purpose I/O port. Port B is only available on the MC68HC908QY1, MC68HC908QY2, and MC68HC908QY4.

12.3.1 Port B Data Register

The port B data register (PTB) contains a data latch for each of the eight port B pins.

Address:

$0001

Bit 7654321Bit 0

Read:

Write:

Reset: Unaffected by reset

PTB7 PTB6 PTB5 PTB4 PTB3 PTB2 PTB1 PTB0

(3)

(5)

Figure 12-5. Port B Data Register (PTB)

PTB[7:0] — Port B Data Bits

These read/write bits are software programmable. Data direction of each port B pin is under the control of the corresponding bit in data direction register B. Reset has no effect on port B data.

MC68HC908QY/QT Family Data Sheet, Rev. 5

100 Freescale Semiconductor

Freescale MC68HC908QY4, MC68HC908QY2, MC68HC908QT2, MC68HC908QY1, MC68HC908QT1 DATA SHEET

Specifications and Main Features

Frequently Asked Questions

User Manual