Intel 8XC196Jx, 8XC196Kx, 8XC196Lx, XC196Kx Supplement To User’s Manual

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8XC196Lx Supplement to

8XC196Kx, 8XC196Jx,

87C196CA User’s Manual

August 2004

Order Number: 272973-003

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herwise, to any intellectual property rights is granted by this document. Except as provided in Intel’s Terms and Conditions

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e saving, or life sustaining applications.

lif

tel may make changes to specifications and product descriptions at any time, without notice.

Designers must not rely on the absence or characteristics of any features or instructions marked "reserved" or "undefined." Intel reserves these for future definition and shall have no responsibility whatsoever for conflicts or incompatibilities arising

om future changes to them.

The 8XC196Lx, 8XC196Kx, 8XC196Jx and 87C196CA microprocessors may contain design defects or errors known as errata which may cause the products to deviate from published specifications. Current characterized errata are available on request.

Contact your local Intel sales office or your distributor to obtain the latest specifications and before placing your product order.

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*Third-party brands and names are the property of their respective owners.

CONTENTS

CHAPTER 1

GUIDE TO THIS MANUAL

1.1 MANUAL CONTENTS................................................................................................... 1-1

1.2 RELATED DOCUMENTS.............................................................................................. 1-2

CHAPTER 2

ARCHITECTURAL OVERVIEW

2.1 MICROCONTROLLER FEATURES.............................................................................. 2-1

2.2 BLOCK DIAGRAM............................................ ............................................. ...... ..... ..... 2-2

2.3 INTERNAL TIMING........................................................................................................ 2-2

2.4 EXTERNAL TIMING...................................................................................................... 2-5

2.5 INTERNAL PERIPHERALS........................................................................................... 2-6

2.5.1 I/O Ports ........................................... ...... ..... ...... ............................................. ..... .. ....2-7

2.5.2 Synchronous Serial I/O Port .....................................................................................2-7

2.5.3 Event Processor Array .............................................................................................. 2-7

2.5.4 J1850 Communications Controller ............................................................................2-7

2.6 DESIGN CONSIDERATIONS........................................................................................ 2-7

CHAPTER 3

ADDRESS SPACE

3.1 ADDRESS PARTITIONS............................................................................................... 3-1

3.2 REGISTER FILE.................................... ............................................. ..... ...... ...... .......... 3-2

3.3 PERIPHERAL SPECIAL-FUNCTION REGISTERS...................................................... 3-4

3.4 WINDOWING................................................................................................................. 3-6

CHAPTER 4

STANDARD AND PTS INTERRUPTS

4.1 INTERRUPT SOURCES, VECTORS, AND PRIORITIES............................................. 4-1

4.2 INTERRUPT REGISTERS............................................................................................. 4-2

4.2.1 Interrupt Mask Registers ............................. ...... ..... ...... ...... ..... ..................................4-3

4.2.2 Interrupt Pending Registers ............................................... .......................................4-4

4.2.3 Peripheral Transaction Server Registers ..................................................................4-6

CHAPTER 5

I/O PORTS

5.1 I/O PORTS OVERVIEW................................................................................................ 5-1

5.2 INTERNAL STRUCTURE FOR PORTS 1, 2, 5, AND 6 (BIDIRECTIONAL PORTS).... 5-1

5.2.1 Configuring Ports 1, 2, 5, and 6 (Bidirectional Ports) ................................................5-3

5.2.2 Special Bidirectional Port Considerations .................................................................5-4

5.3 INTERNAL STRUCTURE FOR PORTS 3 AND 4 (ADDRESS/DATA BUS).................. 5-5

iii

8XC196LX SUPPLEMENT

CHAPTER 6

SYNCHRONOUS SERIAL I/O PORT

6.1 SSIO 0 CLOCK REGISTER........................................................................................... 6-1

6.2 SSIO 1 CLOCK REGISTER........................................................................................... 6-2

CHAPTER 7

EVENT PROCESSOR ARRAY

7.1 EPA FUNCTIONAL OVERVIEW................................................................................... 7-1

7.1.1 EPA Mask Registers .......................................................................... ...... ...... ..... ......7-4

7.1.2 EPA Pending Registers ........ ............................................. ..... ...... ............................7-5

7.1.3 EPA Interrupt Priority Vector Register .......................................................................7-6

CHAPTER 8

J1850 COMMUNICATIONS CONTROLLER

8.1 J1850 FUNCTIONAL OVERVIEW................................................................................. 8-1

8.2 J1850 CONTROLLER SIGNALS AND REGISTERS..................................................... 8-3

8.3 J1850 CONTROLLER OPERATION............................................................................. 8-4

8.3.1 Control State Machine ..............................................................................................8-4

8.3.1.1 Cyclic Redundancy Check Generator ..................................................................8-4

8.3.1.2 Bus Contention .....................................................................................................8-5

8.3.1.3 Bit Arbitration ........................................................................................................8-5

8.3.1.4 Error Detection .....................................................................................................8-5

8.3.2 Symbol Synchronization and Timing Circuitry ...........................................................8-5

8.3.2.1 Clock Prescaler ....................................................................................................8-6

8.3.2.2 Digital Filter ..........................................................................................................8-6

8.3.2.3 Delay Compensation ............................................................................................8-6

8.3.2.4 Symbol Encoding and Decoding ..........................................................................8-6

8.3.3 Bit Arbitration Example .............................................................................................8-7

8.4 MESSAGE FRAMES..................................................................................................... 8-8

8.4.1 Standard Messaging .............................................. ...... ...... .......................................8-9

8.4.1.1 Header .................................................................................................................8-9

8.4.1.2 CRC Byte .............................................................................................................8-9

8.4.1.3 Normalization Bit ..................................................................................................8-9

8.4.1.4 Start and End Message Frame Symbols ............................................................8-10

8.4.2 In-frame Response Me ss agi ng ............................................... ...... ..... .....................8-12

8.4.2.1 IFR Messaging Type 1: Single Byte, Single Responder ....................................8-12

8.4.2.2 IFR Messaging Type 2: Single Byte, Multiple Responders ................................8-12

8.4.2.3 IFR Messaging Type 3: Multiple Bytes, Single Responder ................................8-13

8.5 TRANSMITTING AND RECEIVING MESSAGES....................................................... 8-13

8.5.1 Transmitting Messages ...........................................................................................8-13

8.5.2 Receiving Mess age s ........................ ...... ..... ...... ............................................. .........8-15

8.5.3 IFR Messages .........................................................................................................8-16

CONTENTS

8.6 PROGRAMMING THE J1850 CONTROLLER ............................................................ 8-16

8.6.1 Programming the J1850 Command (J_CMD) Register ..........................................8-16

8.6.2 Programming the J1850 Configuration (J_CFG) Register ......................................8-18

8.6.3 Programming the J1850 Delay Compensation (J_DLY) Register ...........................8-19

8.6.4 Programming the J1850 Status (J_STAT) Register ................................................8-21

CHAPTER 9

MINIMUM HARDWARE CONSIDERATIONS

9.1 IDENTIFYING THE RESET SOURCE........................................................................... 9-1

9.2 DESIGN CONSIDERATIONS FOR 8XC196LA, LB, AND LD ....................................... 9-2

CHAPTER 10

SPECIAL OPERATING MODES

10.1 INTERNAL TIMING...................................................................................................... 10-1

10.2 ENTERING AND EXITING ONCE MODE................................................................... 10-2

CHAPTER 11

PROGRAMMING THE NONVOLATILE MEMORY

11.1 SIGNATURE WORD AND PROGRAMMING VOLTAGE VALUES............................. 11-1

11.2 OTPROM ADDRESS MAP.......................................................................................... 11-1

11.3 SLAVE PROGRAMMING CIRCUIT AND ADDRESS MAP......................................... 11-2

11.4 SERIAL PORT PROGRAMMING CIRCUIT AND ADDRESS MAP............................. 11-4

APPENDIX A

SIGNAL DESCRIPTIONS

A.1 FUNCTIONAL GROUPINGS OF SIGNALS................................................................. A-1

A.2 DEFAULT CONDITIONS.............................................................................................. A-7

GLOSSARY

8XC196LX SUPPLEMENT

FIGURES

Figure Page

2-1 8XC196L

2-2 Clock Circuitry (87C196LA, LB Only)...........................................................................2-3

2-3 Internal Clock Phases (Assumes PLL is Bypassed).....................................................2-4

2-4 Effect of Clock Mode on Internal CLKOUT Frequency.................................................2-5

2-5 Unerasable PROM 1 (USFR1) Register (LA, LB Only)................................................2-6

3-1 Register File Address Map.................. ...... ............................................ ...... ...... ..... ......3-3

4-1 Interrupt Mask (INT_MASK) Register.................................... .......................................4-3

4-2 Interrupt Mask 1 (INT_MASK1) Register......................................................................4-4

4-3 Interrupt Pending (INT_PEND) Register ......................................................................4-5

4-4 Interrupt Pending 1 (INT_PEND1) Register .................................................................4-6

4-5 PTS Select (PTSSEL) Register....................................................................................4-7

4-6 PTS Service (PTSSRV) Register .................................................................................4-8

5-1 Ports 1, 2, 5, and 6 Internal Structure (87C196LA, LB Only) .......................................5-3

5-2 Ports 3 and 4 Internal Structure (87C196LA, LB Only)................................................5-6

6-1 SSIO 0 Clock (SSIO0_CLK) Register...........................................................................6-1

6-2 SSIO 1 Clock (SSIO1_CLK) Register...........................................................................6-2

7-1 EPA Block Diagram (87C196LA, LB Only)...................................................................7-2

7-2 EPA Block Diagram (83C196LD Only).........................................................................7-3

7-3 EPA Interrupt Mask (EPA_MASK) Register.................................................................7-4

7-4 EPA Interrupt Mask 1 (EPA_MASK1) Register.......................... ...... ............................7-4

7-5 EPA Interrupt Pending (EPA_PEND) Register.............................................................7-5

7-6 EPA Interrupt Pending 1 (EPA_PEND1) Register........................................................7-5

7-7 EPA Interrupt Priority Vector Register (EPAIPV)..........................................................7-6

8-1 Integrated J1850 Communications Protocol Solution...................................................8-1

8-2 J1850 Communications Controller Block Diagram.......................................................8-2

8-3 Huntzicker Symbol Definition for J1850........................................................................8-7

8-4 Typical VPW Waveform................................................................................................8-7

8-5 Bit Arbitration Example.................................................................................................8-8

8-6 J1850 Message Frames...............................................................................................8-9

8-7 Huntzicker Symbol Definition for the Normalization Bit..............................................8-10

8-8 Definition for Start and End of Frame Symbols..........................................................8-11

8-9 IFR Type 1 Message Frame.......................................................................................8-12

8-10 IFR Type 2 Message Frame.......................................................................................8-13

8-11 IFR Type 3 Message Frame.......................................................................................8-13

8-13 J1850 Transmit Message Structure............................................................................8-14

8-12 J1850 Transmitter (J_TX) Register............................................................................8-14

8-15 J1850 Receive Message Structure.............................................................................8-15

8-14 J1850 Receiver (J_RX) Register................................................................................8-15

8-16 J1850 Command (J_CMD) Register..........................................................................8-17

8-17 J1850 Configuration (J_CFG) Register......................................................................8-18

8-18 J1850 Delay (J_DLY) Register...................................................................................8-20

8-19 J1850 Status (J_STAT) Register................................................................................8-21

9-1 Reset Source (RSTSRC) Register...............................................................................9-1

10-1 Clock Circuitry (87C196LA, LB Only).........................................................................10-2

Block Diagram............................................................................................2-2

CONTENTS

FIGURES

Figure Page

11-1 Slave Programming Circuit.........................................................................................11-3

11-2 Serial Port Programming Circuit.................................................................................11-4

A-1 87C196LA 52-pin PLCC Package............................. ...... ...... ......................................A-3

A-2 87C196LB 52-pin PLCC Package............................. ...... ...... ......................................A-5

A-3 83C196LD 52-pin PLCC Package............................................................................... A-7

vii

8XC196LX SUPPLEMENT

TABLES

Table Page

1-1 Related Documents......................................................................................................1-2

2-1 Features of the 8XC196Lx and 8XC196Kx Product Famiies.......................................2-1

2-2 State Times at Various Frequencies..................................... ..... ...... ............................2-4

2-3 Relationships Between Input Frequency, Clock Multiplier, and State Times ...............2-5

2-4 UPROM Programming Values and Locations..............................................................2-6

3-1 Address Map................................................................................................................3-1

3-2 Register File Memory Addresses ................................................................................. 3-3

3-3 8XC196L

3-4 Windows.......................................................................................................................3-6

4-1 Interrupt Sources, Vectors, and Prioriti es........................ ...... ..... ...... ............................4-2

5-1 Microcontroller Ports.....................................................................................................5-1

7-1 EPA Channels.......................... ..... ...... ...... ............................................ ...... ...... ..... ......7-1

7-2 EPA Interrupt Priority Vectors.......................................................................................7-6

8-1 J1850 Controller Signals ..............................................................................................8-3

8-2 Control and Status Registers .......................................................................................8-3

8-3 Relationships Between Input Frequency, PLL, and Prescaler Bits..............................8-6

8-4 Huntzicker Symbol Timing Characteristics.................................................................8-11

11-1 Signature Word and Programming Voltage Values....................................................11-1

11-2 87C196LA, LB

11-3 Slave Programming Mode Address Map....................................................................11-3

11-4 Serial Port Programming Mode Address Map............................................................11-5

A-1 87C196LA Signals Arranged by Functional Categories..............................................A-2

A-2 87C196LB Signals Arranged by Functional Categories..............................................A-4

A-3 83C196LD Signals Arranged by Functional Categories..............................................A-6

A-4 Definition of Status Symbols .......................................................................................A-7

A-5 87C196LA, LB Default Signal Conditions....................................................................A-8

A-6 83C196LD Default Signal Conditions..........................................................................A-9

Peripheral SFRs.........................................................................................3-4

OTPROM Address Map.....................................................................11-2

viii

Guide to This Manual

CHAPTER 1

GUIDE TO THIS MANUAL

This document is a supplement to the 8XC196Kx, 8XC196Jx, 87C 196CA Microcontr oller Family User’s Manual. It descri bes the differences between the 8XC1 96Lx and the 8XC196 Kx family of microcontrollers. For information not found in th is supplement, please consult the 8XC196Kx, 8XC196Jx, 87C196CA Microcontroller Family User’s Manual (order number 272258) or the 8XC196Lx datasheets listed in the “Related Documents” section of this chapter.

1.1 MANUAL CONTENTS

This supplement contains several chapters, an appendix, a glossary, and an index. This chapter, Chapter 1, provides an overview of the supplement. This section summarizes the contents of the remaining chapters and appendixes. The remainder of this chapter provides references to related documentation.

Chapter 2 — Architectural Overview — compares the features of the 8XC196Lx microcon- troller family with those of the 8XC196Kx microcontroller family an d des cri bes t he 87 C19 6LA, LB internal clock circuitry.

Chapter 3 — Address Space — describes the addressable memory space of the 52-pin 8XC196Lx, lists the peripheral special-function registers (SFRs), and provides tables of WSR values for windowing higher memory into the lower register file for direct access.

Chapter 4 — Standard and PTS Interrupts — describes the additional interrupts for the

87C196LB’s J1850 communications controller peripheral and the SFRs that support those interrupts.

Chapter 5 — I/O Ports — describes the port differences and explains the change in the port reset

state from a “logic 1” to a “logic 0” on the 87C196LA, LB.

Chapter 6 — Synchronous Serial I/O Port — describes the enhanced synchronous serial I/O (SSIO) port and explains how to program the two additional p e ripheral SFRs.

Chapter 7 — Event Processor Array — describes the event processor array channel dif ferences.

Chapter 8 — J1850 Communications Controller — describes the 87C196LB’s integrated J1850 controller and explains how to configure it.

Chapter 9 — Minimum Hardware Considerations — describes device reset options through the reset source register, and discusses hardware design considerations.

Chapter 10 — Special Operating Modes — illustrates the internal clock control circuitry of the 87C196LA, LB and describes how to enter and exit on-circuit emulation (ONCE) mode.

Chapter 1 1 — Programm ing the Nonvol atile Memo ry — describes the memory maps and rec-

ommended circuits to support programming of the 87C196LA, LB’s 24 Kbytes of OTPROM.

1-1

8XC196LX SUPPLEMENT

Appendix A — Signal Descriptions — provides reference information for the 8XC196Lx de- vice pins, including descript ions of the pin function s, reset status of the I/O and control pi ns, and package pin assignments.

Glossary — d e fines terms with special meaning used throughout this supp lement. Index — lists key topics with page number references.

1.2 RELATED DOCUMENTS

T a ble 1-1 lists additional do cumen ts that yo u may fi nd useful in des igning systems inco rporatin g the 8XC196Lx microcontrollers.

Table 1-1. Related Documents

Title and Description Order Number

8XC196Kx, 8XC196Jx, 87C196CA Microcontroller Family User’s Manual 87C196LA-20 MHz CHMOS 16-Bit Microcontroller Automotive 87C196LB-20 MHz CHMOS 16-Bit Microcontroller Automotive 83C196LD CHMOS 16-Bit Microcontroller Automotive

datasheet 272805

datasheet 272806 datasheet 272807

272258

1-2

Architectural Overview

CHAPTER 2

ARCHITECTURAL OVERVIEW

This chapter describes architectural differences between the 8XC196L x (87C196LA, 8 7C196LB, and 83C196LD) and the 8XC196Kx (8XC196Kx, 8XC196Jx, and 87C196CA) microcontroller families. Both the 8XC196Lx and the 8XC196Kx are designed for high-speed calculations and fast I/O, and share a common architecture and instruction set with few deviations. This chapter provides a high-level overview of the deviations between the two families.

NOTE

This supplement describes two produc t fami lies within the MCS® 96 microcontroller family. For brevity, the name 8XC196Lx is used when the discussion applies to all three Lx controllers. Likewise, th e name 8XC196 Kx is used when the discussion applies to all the Kx, Jx, and CA controllers.

2.1 MICROCONTROLLER FEATURES

Table 2-1 lists the features of the 8XC196Lx and the 8XC196Kx.

Table 2-1. Features of the 8XC196Lx and 8XC196Kx Product Famiies

OTPROM/

Device Pins

87C196LA 52 24 K 768 —416 3 6— — 1 87C196LB 52 24 K 768 — 41 6 3 6 — 1 1 83C196LD 52 16 K 384 — 41 6 3 — — — 1 8XC196JV 52 48 K 1536 512 41 6 3 6 — — 1 8XC196KT 68 32 K 1024 512 56 10 3 8 — — 2 8XC196JT 52 32 K 1024 512 41 6 3 6 — — 1 87C196CA 68 32 K 1024 256 51 6 3 6 1 — 2 8XC196KR 68 16 K 512 256 56 10 3 8 — — 2 8XC196JR 52 16 K 512 256 41 6 3 6 — — 1

NOTES:

1. Optional. The second character of the device name indicates the presence and type of nonvolatile memory. 80C196

2. Register RAM amounts include the 24 bytes allocated to core SFRs and the stack pointer.

EPROM/ ROM (1)

= none; 83C196xx = ROM; 87C196xx = OTPROM or EPROM.

RAM (2)

Code

RAM

I/O

Pins

EPA Pins

SIO/

SSIO

Ports

A/D CAN J1850

Ext.

Interrupt

Pins

2-1

8XC196LX SUPPLEMENT

2.2 BLOCK DIAGRAM

Figure 2-1 is a simplified block diagram that shows the major blocks within the microcontroller. Observe that the slave port peripheral does not exist on the 8XC196Lx.

(CPU, Memory

Controller)

Clock and

Power Mgmt.

SIO

Note:

The J1850 peripheral is unique to the 87C196LB device. The A/D peripheral is unique to the 87C196LA, LB devices.

2.3 INTERNAL TIMING

Core

Optional

ROM/

OTPROM

Optional

Code/Data

RAM

EPA

Interrupt

Controller

Peripheral

Transaction

A/DSSIOI/O

Server

WDT

Figure 2-1. 8XC196Lx Block Diagram

J1850

A5253-01

The 87C196LA, LB clock circuitry (Figure 2-2) implem ents a phase-locked loop and clock multiplier circuitry , which can substantially increase the CPU clock rate while using a lower-frequency input clock. The clock circuitry accepts an input clock signal on XTAL1 provided by an external crystal or os cill at o r. Depending on the value of the PLLEN pin, this frequency is ro ut ed either through the phase-locked loo p and m ultipl ier or directly to the d ivide -by-two circuit. The multiplier circuitry can double the input frequency (F

) before the frequency (f) reaches the

XTAL1

divide-by-two circuitry. The clock generators accept the divided input frequency (f/2) from the divide-by-two circuit and produce two nonoverlapping internal timing signals, PH1 and PH2. These signals are active when high.

NOTE

This manual uses lowercase “f” to represent the internal clock frequency. For the 87C196LA and LB, f is equal to either F

XTAL1

or 2F

, depending on th e

XTAL1

clock multiplier mode, which is controlled by the PLLEN input pin.

2-2

ARCHITECTURAL OVERVIEW

XTAL1

XTAL2

XTAL1

Disable Oscillator (Powerdown)

XTAL1

Disable

PLL

(Powerdown)

PLLEN

XTAL1

Divide by two

Circuit

Clock

Generators

Phase

Comparator

Phase-locked

Oscillator

Phase-locked Loop

Clock Multiplier

Disable Clock Input (Powerdown)

f/2

Clock

Failure

Detection

f/2

Filter

To reset logic

Disable Clocks (Idle, Powerdown)

CPU Clocks (PH1, PH2)

Peripheral Clocks (PH1, PH2)

Programmable

Divider

(CLK1:0)

OSC

CLKOUT

Disable Clocks (Powerdown)

A5290-01

Figure 2-2. Clock Circuitry (87C196LA, LB Only)

The rising edges of PH1 and PH2 generate the internal CLKOUT signal (Figure 2-3). The clock circuitry routes separ ate int ernal clock signals t o the CPU and the per ipher als to pr ovid e flexibil ity in power management. It also outputs the CLKOUT signal on the CLKOUT pin. Because of the complex logic in the clock circuitry, the signal on the CLKOUT pin is a delayed version of the internal CLKOUT signal. This delay varies with temperature and voltage.

2-3

8XC196LX SUPPLEMENT

PH1 (in MHz)

-- - PH2==

XTAL1

PH1

PH2

CLKOUT

1 State Time

Phase 1 Phase 2

A0805-01

Figure 2-3. Internal Clock Phases (Assumes PLL is Bypassed)

The combined period of phase 1 and phase 2 of the internal CLKOUT signal defines the basic time unit known as a state time or state. Table 2-2 lists state time durations at various frequencies.

Table 2-2. State Times at Various Frequencies

(Frequency Input to the

Divide-by-two Circuit)

8 MHz 250 ns 12 MHz 167 ns 16 MHz 125 ns 20 MHz 100 ns

State Time

The following formulas calculate the frequency of PH1 and PH2, the duration of a state time, and the duration of a clock period (t).

State Time (in µs)

-- -= t

-- -=

Because the device can operate at many frequencies, this manual defines time requirements (such as instruction execution times) in terms of state times rather than specific measurements. Datasheets list AC characteristics in terms of clock periods (t; sometimes called T

Figure 2-4 illustrates the timing relationships between the input frequency (F frequency (f), and the CLKOUT signal with each PLLEN pin configuration . Table 2-3 details the relationships between the input frequency (F the clock period (t), and state times.

2-4

osc

), the operatin g

XTAL1

), the PLLEN pin, the operating frequency (f),

XTAL1

(16 MHz)

PLLEN = 0

Internal

CLKOUT

PLLEN = 1

Internal

CLKOUT

ARCHITECTURAL OVERVIEW

XHCH

t = 62.5ns

t = 31.25ns

A3376-01

Figure 2-4. Effect of Clock Mode on Internal CLKOUT Frequency

Table 2-3. Relationships Between Input Frequency, Clock Multiplier, and State Times

XTAL1

(Frequency

on XTAL1)

PLLEN Multiplier

(Input Frequency to

the Divide-by-two Circuit)

4 MHz 0 1 4 MHz 250 ns 500 ns

8 MHz 0 1 8 MHz 125 ns 250 ns 12 MHz 0 1 12 MHz 83.5 ns 167 ns 16 MHz 0 1 16 MHz 62.5 ns 125 ns 20 MHz 0 1 20 MHz 50 ns 100 ns

4 MHz 1 2 8 MHz 125 ns 250 ns

8 MHz 1 2 16 MHz 62.5 ns 125 ns 10 MHz 1 2 20 MHz 50 ns 100 ns

(Clock

Period)

State Time

2.4 EXTERNAL TIMING

You can control the output frequency on the CLKOUT pin by programming two uneraseable PROM bits. Figure 2-5 illustrates the read-only USFR1, which reflects the state of the unerasable PROM bits. You can select one of three frequencies: f/2, f/4, or f/8. As Figure 2-2 on page 2-3 shows, the configurable divider accepts the output of the clock generators (f/2) and further divides that frequency to produce the desired output frequ ency . The CLK1:0 bits control the divisor (divide f/2 by either 1, 2, or 4).

2-5

8XC196LX SUPPLEMENT

USFR1 (read only)

The UPROM special-function register 1 (USFR1) reflects the status of unerasable, programmable read-only memory (UPROM) locations. This read-only register reflects the status of two bits that control the output frequency on CLKOUT.

7 0

— — — — — — CLK1 CLK0

Bit

Number

7:2 — Reserved. 1:0 CLK1:0 CLKOUT Control

Bit

Mnemonic

Function

These bits reflect the programmed frequency of the CLKOUT signal:

CLK1 CLK0

0 0 divide by 1 (CLKOUT = f/2) 0 1 divide by 2 (CLKOUT = f/4) 1 0 divide by 4 (CLKOUT = f/8) 1 1 divide by 1 (CLKOUT = f/2)

Address:

Reset State:

1FF2H

XXH

Figure 2-5. Unerasable PROM 1 (USFR1) Register (LA, LB Only)

T o pr ogram these bits, write the correct value to the locations show n in Table 2-4 using slav e programming mode. During normal op eration, yo u can determ ine the values of these bits by read ing the UPROM SFR (Figure 2-5).

You can verify a UPROM bit to make sure it programmed, but you cannot erase it. For this reason, Intel cannot test the bits before shipment. However, Intel does test the features that the UPROM bits enable, so the only und etectable defects are (unlikely ) defects within the UPROM cells themselves.

Table 2-4. UPROM Programming Values and Locations

T o set this bit Write this value To this location

CLK0 0001H 0768H CLK1 0002H 0728H

2.5 INTERNAL PERIPHERALS

The internal peripheral modules provide special functions for a variety o f applications. Th is section provides a brief description of the peripherals that differ between the 8XC1 96Lx and the 8XC196Kx fami lies.

2-6

ARCHITECTURAL OVERVIEW

2.5.1 I/O Ports

The I/O ports of the 8XC196 Lx are functionall y identical to those of the 8XC196J x. However , o n the 87C196LA and LB the reset state level of all 41 general-purpose I/O pins has changed from

a weak logic “1” (wk1) to a weak logic “0” (wk0).

2.5.2 Synchronous Serial I/O Port

The synchronous serial I/O (SSIO) port on t he 8XC196Lx has been enhance d, implementing two new special function registers (SSIO0_CLK and SSIO1_CLK) that allow you to select the operating mode and configure the phase and polarity of the serial clock signals.

2.5.3 Event Processor Array

The 8XC196 Lx’s event processor array (EPA) is functionally identical to that of the 8XC196Jx, except that it has only two EPA capture/compare chann els without pi ns instead of four. In addition the LD has no compare-only channels.

2.5.4 J1850 Communications Controller

The 87C196LB m icrocontrol ler has a p eripheral not found on the 8XC196Kx microcontrollers or any other Lx microcontroller, the J1850 peripheral. The J1850 communications controller manages communications between m ultiple network n odes. This integrated p eripheral supports the

10.4 Kb/s VPW (variable pulse-width) medium-speed, class B, in-vehicle network protocol. It also supports both the standard and in-frame re sponse (IFR) message framing as specified by the Society of Automotive Engineering (SAE) J1850 (revised May 1994) technical standards.

2.6 DESIGN CONSIDERATIONS

With the exception of a few new multiplexed functions, the 8XC196L x microcontrollers are pin compatible with the 8 XC196Jx microcontrollers. The 8XC196Jx microcontrollers are 52-lead versions of 8XC196Kx microcontrollers. For registers that are implemented in both the 8XC196Lx and the 8XC196Jx, configure the 8XC196Lx register as you would for the 8XC196 Jx unless differences are noted in this supplement.

2-7

Address Space

CHAPTER 3

ADDRESS SPACE

This chapter describes the differences in the address space of the 8XC196Lx from that of the 8XC196Kx.

3.1 ADDRESS PARTITIONS

Table 3-1 is an address map of the 8XC196Lx and 8XC196Kx microcontroller family members.

Table 3-1. Address Map

Device and Hex Address Range

Description

FFFF A000

9FFF

2080

207F 2000

1FFF 1FE0

1FDF

1F00

1EFF 1E00

1DFF 1C00

—————

NOTES:

1. After a reset, the device fetches its first instruction from 2080H.

2. The content or function of these locations may change in future device revisions, in which case a program that relies on a location in this range might not function properly.

JR, KR

FFFF

6000

5FFF

2080

207F 2000

1FFF 1FE0

1FDF

1F00

—————CAN SFRs

1EFF 1C00

FFFF

6000

5FFF

2080

207F 2000

1FFF 1FE0

1FDF

1F00

1EFF 1C00

LA, LB

FFFF 8000

7FFF 2080

207F 2000

1FFF 1FE0

1FDF

1F00

1EFF

0300

JT, KT

FFFF A000

9FFF

2080

207F

2000

1FFF 1FE0

1FDF 1F00

1EFF 1C00

FFFF E000

DFFF

2080

207F 2000

1FFF 1FE0

1FDF

1F00

1EFF 1E00

1DFF 1C00

External device (memory or I/O) connected to address/data bus

Program memory (internal nonvolatile or external memory); see Note 1

Special-purpose memory (internal nonvolatile or external memory)

Memory-mapped SFRs

Peripheral SFRs (Includes J1850 SFRs on 87C196LB)

External device (memory or I/O) connected to address/data bus; (future SFR expansion; see Note 2)

Addressing

Modes

Indirect or indexed

Indirect, indexed, or windowed direct

Indirect or indexed

Indirect, indexed, or windowed direct

3-1

8XC196LX SUPPLEMENT

Table 3-1. Address Map (Continued)

Device and Hex Address Range

Description

1BFF

0600

05FF

0400

03FF

0100

00FF

0000

External device (memory or I/O) connected to address/data bus

Internal code or data RAM External device (memory

or I/O) connected to address/data bus

Upper register file (general-purpose register RAM)

Lower register file (register RAM, stack pointer, and CPU SFRs)

1BFF

0500

04FF

0400

—

03FF

0100

00FF

0000

NOTES:

1. After a reset, the device fetches its first instruction from 2080H.

2. The content or function of these locations may change in future device revisions, in which case a program that relies on a location in this range might not function properly.

JR, KR

1BFF

0500

04FF

0400

03FF

0200

01FF

0100

00FF

0000

1BFF

0600

——

05FF

0180

017F 0100

00FF

0000

LA, LB

—

———

02FF 0100

00FF 0000

JT, KT

1BFF

0600

05FF

0400

03FF

0100

00FF

0000

Addressing

Indirect or indexed

Indirect, indexed, or windowed direct

Direct, indirect, or indexed

Modes

3.2 REGISTER FILE

Figure 3-1 compares the register file addresses of the 8XC196Lx and 8XC196Kx. The register file in Figure 3 -1 is divided into an up per regis ter f ile and a lower reg ister file . The u pper reg ister file consists of general-purpose register RAM. The lower register file contains general-purpose register RAM along with the stack pointer (SP) and the CPU special-function registers (SFRs).

Table 3-2 lists the register file memory addresses. The RALU accesses the lower register file directly, without the use of the memory controller. It also accesses a windowed location d irectly (see “Windowing” on page 3-6). The upper register file and the peripheral SFRs can be win-

dowed. Registers in the lower register file and registers being windowed can be accessed with register-direct addressing.

NOTE

The register file must not contain code. An attempt to execute an instruction from a location in the register file causes the memory controller to fetch the instruction from external me mory.

3-2

General-purpose

ADDRESS SPACE

Address

03FFH (CA, JT, JV, KT)

02FFH (LA, LB)

01FFH (JR, KR)

017FH (LD)

Address

03FFH

0100H 00FFH

0000H

Upper

Lower

Figure 3-1. Register File Address Map

Table 3-2. Register File Memory Addresses

Device and Hex Address Range

JV CA,JT,KT LA, LB JR, KR LD

1DFF 1C00

03FF 0100

00FF 001A

0019 0018

0017 0000

— — — — Register RAM

03FF

0100

00FF 001A

0019 0018

0017 0000

02FF 0100

00FF 001A

0019 0018

0017 0000

01FF 0100

00FF 001A

0019 0018

0017 0000

017F 0100

00FF 001A

0019 0018

0017 0000

General-purpose

Stack Pointer

CPU SFRs

Description Addressing Modes

Upper register file (register RAM)

Lower register file (register RAM)

Lower register file (stack pointer)

Lower register file (CPU SFRs)

0100H 00FFH

001AH 0019H 0018H

0017H 0000H

A5260-01

Indirect, indexed, or windowed direct

Direct, indirect, or indexed

3-3

8XC196LX SUPPLEMENT

3.3 PERIPHERAL SPECIAL-FUNCTION REGISTERS

T a ble 3- 3 li sts the pe ripheral SFR address es. Hi ghlig hted addr esses are un ique to th e 8XC19 6Lx.

Table 3-3. 8XC196Lx Peripheral SFRs

Ports 3, 4, 5, and UPROM SFRs Ports 0, 1, 2, and 6 SFRs

Address High (Odd) Byte Low (Even) Byte Address High (Odd) Byte Low (Even) Byte

1FFEH P4_PIN P3_PIN 1FDEH Reserved Reserved 1FFCH P4_REG P3_REG 1FDCH Reser ved Reserved 1FFAH SLP_CON SLP_CMD 1FDAH Reserved P0_PIN

1FF8H Reserved SLP_STAT 1FD8H Reserved Reserved 1FF6H P5_PIN USFR 1FD6H P6_PIN P1_PIN 1FF4H P5_REG P34_DRV 1FD4H P6_REG P1_REG 1FF2H P5_DIR USFR1 (LA, LB) 1FD2H P6_DIR P1_DIR

1FF0H P5_MODE Reserved 1FD0H P6_MODE P1_MODE 1FEEH Reserved Reserved 1FCEH P2_PIN Reserved 1FECH Reserved Reserved 1FCCH P2_REG Reserved 1FEAH Reserved Reserved 1FCAH P2_DIR Reserved 1FE8H Reserved Reserved 1FC8H P2_MODE Reserved 1FE6H Reserved Reserved 1FC6H Reserved Reserved 1FE4H Reserved Reserved 1FC4H Reserved Reserved 1FE2H Reserved Reserved 1FC2H Reserved Reserved 1FE0H Reserved Reserved 1FC0H Reserved Reserved

†

Must be addressed as a word.

3-4

ADDRESS SPACE

Table 3-3. 8XC196Lx Peripheral SFRs (Continued)

SIO and SSIO SFRs EPA SFRs (Continued)

Address High (Odd) Byte Low (Even) Byte Address High (Odd) Byte Low (Even) Byte

†

1FBEH R eserved Reserved 1FBCH SP_BAUD (H) SP_BAUD (L) 1F7CH Reserved EPA7_CON 1FBAH SP_CON SBUF_TX 1FB8H SP_STATUS S BUF_RX 1F78H Reserved EPA6_CON 1FB6H SSIO1_CLK Reserved 1FB4H SSIO0_CLK SSIO_BAUD 1F74H Reserved EPA5_CON 1FB2H SSIO1_CON SSIO1_BUF 1FB0H SSIO0_CON SSIO0_BUF 1F70H Reserved EPA4_CON

A/D SFRs (LA, LB Only)

Address High (Odd) Byte Low (Even) Byte

1FAEH AD_TIME AD_TEST 1FACH Reserved AD_COMMAND 1F68H Reserved EPA2_CON 1FAAH AD_RESULT (H) AD_RESULT (L)

EPA Interrupt SFRs

Address High (Odd) Byte Low (Even) Byte

1FA8H Reserved E PAIPV 1F60H Reserved EPA0_CON

1FA6H Reserved EPA_PEND1 J1850 SFRs (LB Only)

1FA4H Reserved EPA_MASK1 Address High (Odd) Byte Low (Even) Byte

†

1FA2H EPA_PEND (H) EPA_PEND (L) 1F5EH Reserved Reserved

†

1FA0H EPA_MASK (H) EPA_MASK (L) 1F5CH Reserved Reserv ed

Timer 1, Timer 2, and EPA SFRs 1F5AH Reserved Reserv ed

Address High (Odd) Byte Low (Even) Byte 1F58H Reserved J_DLY

†

1F9EH TIMER2 (H) TIMER2 (L) 1F56H Reserved Reserved

1F9CH Reserved T2CONTROL 1F54H Reserved J_CFG

†

1F9AH TIMER1 (H) TIMER1 (L) 1F52H J_STAT J_RX 1F98H Reserved T1CONTROL 1F50H J_CMD J_TX 1F96H Reserved Reserved 1F94H Reserved Reserved 1F92H Reserved RST_SRC 1F90H Reserved Reserved

EPA SFRs

Address High (Odd) Byte Low (Even) Byte

†

1F8EH COMP1_TIME (H) COMP1_TIME (L)

1F8CH Reserved COMP1_CON

†

1F8AH COMP0_TIME (H) COMP0_TIME (L) 1F88H Reserved COMP0_CON

†

1F86H EPA9_TIME (H) EPA9_TIME (L) 1F84H Reserved EPA9_CON

†

1F82H EPA8_TIME (H) EPA8_TIME (L) 1F80H Reserved EPA8_CON

†

Must be addressed as a word.

1F7EH EPA7_TIME (H) EPA7_TIME (L)

†

1F7AH EPA6_TIME (H) EPA6_TIME (L)

†

1F76H EPA5_TIME (H) EPA5_TIME (L)

†

1F72H EPA4_TIME (H) EPA4_TIME (L)

†

1F6EH EPA3_TIME (H) EPA3_TIME (L)

†

1F6CH EPA3_CON (H) EPA3_CON (L)

†

1F6AH EPA2_TIME (H) EPA2_TIME (L)

†

1F66H EPA1_TIME (H) EPA1_TIME (L)

†

1F64H EPA1_CON (H) EPA1_CON (L)

†

1F62H EPA0_TIME (H) EPA0_TIME (L)

3-5

8XC196LX SUPPLEMENT

3.4 WINDOWING

Windowing maps a segment of higher memory (the upper register file or peripheral SFRs) into the lower register file. The window selection register (WSR) selects a 32-, 64- or 128-byte segment of higher memory to be windowed into the top of the lower register file space. Table 3-4 lists the WSR values for windowing the upper register file for both the 8XC196Lx and 8XC196Kx.

Table 3-4. Windows

Base

Address

Peripheral SFRs

1FE0H 7FH (Note) 1FC0H 7EH 1FA0H 7DH

1F60H 7BH 1F40H 7AH 1F20H 79H

CAN Peripheral SFRs (87C196CA Only)

1EE0H 77H 1EC0H 76H 1EA0H 75H

1E60H 73H

1E40H 72H

1E20H 71H

WSR Value

for 32-byte Window

(00E0–00FFH)

WSR Value

for 64-byte Window

(00C0–00FFH)

3FH (Note)

3EH1F80H 7CH

3DH

3CH1F00H 78H

3BH

3AH1E80H 74H

39H

38H1E00H 70H

WSR Value for

128-byte

Window

(0080–00FFH)

1FH (Note)

1EH

1DH

1CH

1DE0H 6FH 1DC0H 6EH 1DA0H 6DH

1D60H 6BH 1D40H 6AH 1D20H 69H

NOTE: Locations 1FE0–1FFFH contain memory-mapped SFRs that cannot be accessed through a

window. Reading these locations through a window returns FFH; writing these locations through a window has no effect.

3-6

37H

36H1D80H 6CH

35H

34H1D00H 68H

1BH

1AH

Table 3-4. Windows (Continued)

ADDRESS SPACE

Base

Address

1CE0H 67H 1CC0H 66H 1CA0H 65H

1C60H 63H 1C40H 62H 1C20H 61H

Upper Register File (CA, JT, JV, KT)

03E0H 5FH 03C0H 5EH

03A0H 5DH

0360H 5BH

0340H 5AH

0320H 59H

WSR Value

for 32-byte Window

(00E0–00FFH)

WSR Value

for 64-byte Window

(00C0–00FFH)

33H

32H1C80H 64H

31H

30H1C00H 60H

2FH

2EH0380H 5CH

2DH

2CH0300H 58H

WSR Value for

128-byte

Window

(0080–00FFH)

19H

18H

17H

16H

Upper Register File (CA, JT, JV, KT, LA, LB)

02E0H 57H 02C0H 56H

02A0H 55H

0260H 53H

0240H 52H

0220H 51H

Upper Register File (CA, JR, JT, JV, KR, KT, LA, LB)

01E0H 4FH 01C0H 4EH

01A0H 4DH

NOTE: Locations 1FE0–1FFFH contain memory-mapped SFRs that cannot be accessed through a

window. Reading these locations through a window returns FFH; writing these locations through a window has no effect.

2BH

2AH0280H 5 4H

29H

28H0200H 50H

27H

26H0180H 4CH

15H

14H

13H

3-7

8XC196LX SUPPLEMENT

Table 3-4. Windows (Continued)

Base

Address

Upper Register File (CA, JR, JT, JV, KR, KT, LA, LB, LD)

0160H 4BH

0140H 4AH

0120H 49H

NOTE: Locations 1FE0–1FFFH contain memory-mapped SFRs that cannot be accessed through a

window. Reading these locations through a window returns FFH; writing these locations through a window has no effect.

WSR Value

for 32-byte Window

(00E0–00FFH)

WSR Value

for 64-byte Window

(00C0–00FFH)

25H

24H0100H 48H

WSR Value for

128-byte

Window

(0080–00FFH)

12H

3-8

Standard and PTS Interrupts

CHAPTER 4

STANDARD AND PTS INTERRUPTS

The interrupt structur e of the 8XC196Lx is the same as that of the 8XC 196Jx. The only diffe rence is that the slave port interrupts (INT08:06) now support the J1850 controller peripheral.

4.1 INTERRUPT SOURCES, VECTORS, AND PRIORITIES

Table 4- 1 lists the 8XC196Lx’s interrupts sources, default priorities (30 is highest and 0 is lowest), and vector addresses.

4-1

8XC196LX SUPPLEMENT

Table 4-1. Interrupt Sources, Vectors, and Priorities

Interrupt Source Mnemonic

Nonmaskable Interrupt NMI

Interrupt Controller

Service

†

Name

†

INT15 203EH 30 ———

Vector

Priority

PTS Servi ce

Name

Vector

EXTINT Pin EXTINT INT14 203CH 14 PTS14 205CH 29 Reserved — INT13 203AH 13 PTS13 205AH 28 SIO Receive RI INT12 2038H 12 PTS12 2058H 27 SIO Transmit TI INT11 2036H 11 PTS11 2056H 26 SSIO Channel 1 Transfer SSIO1 INT10 2034H 10 PTS10 2054H 25 SSIO Channel 0 Transfer SSIO0 INT09 2032H 09 PTS09 2052H 24 J1850 Status (LB only) J1850ST INT08 2030H 08 PTS08 2050H 23 Reserved (LA, LD) — INT08 2030H 08 PTS08 2050H 23 Unimplemented Opcode — — 2012H — — — — Software TRAP Instruction — — 2010H — — — — J1850 Receive (LB only) J1850RX INT07 200EH 07 PTS07 204EH 22 Reserved (LA, LD) — INT07 200EH 07 PTS07 204EH 22 J1850 Transmit (LB only) J1850TX INT06 200CH 06 PTS06 204CH 21 Reserved (LA, LD) — INT06 200CH 06 PTS06 204CH 21 A/D Conv. Complete (LA, LB) AD_DONE INT05 200AH 05 PTS05 204AH 20 Reserved (LD) — INT05 200AH 05 PTS05 204AH 20 EPA Capture/Compare 0 EPA0 INT04 2008H 04 PTS04 2048H 19 EPA Capture/Compare 1 EPA1 INT03 2006H 03 PTS03 2046H 18 EPA Capture/Compare 2 EPA2 INT02 2004H 02 PTS02 2044H 17 EPA Capture/Compare 3 EPA3 INT01 2002H 01 PTS01 2042H 16 EPA Capture/Compare 6–9,

INT00 2000H 00 PTS00 2040H 15

††

EPA

EPA 0–3, 8–9 Overrun,

†††

EPA Compare 0–1

, Timer 1 Overflow, & Timer 2 Overflow

†

The NMI pin is not bonded out on the 8XC196Lx. To protect against glitches, create a dummy interrupt service routine that contains a RET instruction.

††

These interrupts are individually prioritized in the EPAIPV register. Read the EPA pending registers (EPA_PEND and EPA_PE ND1) to determine which source caused the interrupt.

†††

87C196LA, LB only. The 83C196LD has no EPA compare-only channels.

Priority

4.2 INTERRUPT REGISTERS

This section describes the changes in the interrupt register bit definitions for the 8XC196Lx family .

4-2

STANDARD AND PTS INTERRUPTS

4.2.1 Interrupt Mask Registers

Figures 4-1 and 4-2 illustrate the interrupt mask registers for the 8XC196Lx microcontrollers.

INT_MASK

Address:

Reset State:

0008H

00H

The interrupt mask (INT_MASK) register enables or disables (masks) individual interrupt requests. (The EI and DI instructions enable and disable servicing of all maskable interrupts.) INT_MASK is the low byte of the processor status word (PSW). PUSHF or PUSHA saves the contents of this register onto the stack and then clears this register. Interrupt calls cannot occur immediately following a push instruction. POPF or POPA restores it.

7 0

— — AD EPA0 EPA1 EPA2 EPA3 EPA

7 0

J1850RX J1850TX AD EPA0 EPA1 EPA2 EPA3 EPA

7 0

Bit

Number

†

7:0

— — — EPA0 EPA1 EPA2 EPA3 EPA

Function

Setting a bit enables the corresponding interrupt.

Bit Mnemonic Interrupt Description

J1850RX J1850 Receive (LB only) J1850TX J1850 Transmit (LB only) AD A/D Conversion Complete (LA, LB) EPA0 EPA Capture/Compare Channel 0 EPA1 EPA Capture/Compare Channel 1 EPA2 EPA Capture/Compare Channel 2 EPA3 EPA Capture/Compare Channel 3

††

EPA

††

EPA 6–9 capture/compare channel events, EPA 0–1 compare channel events

Shared EPA interrupt

†††

, EPA

0–3 and 8–9 capture/compare overruns, and timer overflows can generate this

multiplexed interrupt. The EPA mask and pending registers decode the EPA

interrupt. Write the EPA mask registers to enable the interrupt sources; read the EPA pending registers to determine which source caused the interrupt.

†††

87C196LA, LB only.

†

Bits 6–7 are reserved on the 87C196LA, and bits 5–7 are reserved on the 83C196LD. For compatibility with future devices, write zeros to these bits.

Figure 4-1. Interrupt Mask (INT_MASK) Register

4-3

8XC196LX SUPPLEMENT

INT_MASK1

Address:

Reset State:

0013H

00H

The interrupt mask 1 (INT_MASK1) register enables or disables (masks) individual interrupt requests. (The EI and DI instructions enable and disable servicing of all maskable interrupts.) INT_MASK1 can be read from or written to as a byte register. PUSHA saves this register on the stack and POPA restores it.

7 0

NMI EXTINT — RI TI SSIO1 SSIO0 J1850ST

7 0

LA, LD

Bit

Number

†

7:0

NMI EXTINT — RI TI SSIO1 SSIO0 —

Function

Setting a bit enables the corresponding interrupt.

Bit Mnemonic Interrupt Description

NMI

††

Nonmaskable Interrupt EXTINT EXTINT Pin Reserved —

RI SIO Receive TI SIO Transmit SSIO1 SSIO1 Transfer SSIO0 SSIO0 Transfer J1850ST J1850 Status (LB only)

††

NMI is always enabled. This nonfunctional mask bit exists for design symmetry with the INT_PEND1 register. Always write zero to this bit.

†

Bit 5 is reserved on the 8XC196Lx devices, and bit 0 is reserved on the 87C196LA and 83C196LD. For compatibility with future devices, always write zeros to these bits.

Figure 4-2. Interrupt Mask 1 (INT_MASK1) Register

4.2.2 Interrupt Pending Registers

Figures 4-3 and 4-4 illustrate the interrupt pending registers for the 8XC196Lx microcontrollers.

4-4

STANDARD AND PTS INTERRUPTS

INT_PEND

Address:

Reset State:

0009H

00H

When hardware detects an interrupt request, it sets the corresponding bit in the interrupt pending (INT_PEND or INT_PEND1) registers. When the vector is taken, the hardware clears the pending bit. Software can generate an interrupt by setting the corresponding interrupt pending bit.

7 0

— — AD EPA0 EPA1 EPA2 EPA3 EPA

7 0

J1850RX J1850TX AD EPA0 EPA1 EPA2 EPA3 EPA

7 0

Bit

Number

†

7:0

— — — EPA0 EPA1 EPA2 EPA3 EPA

Function

Any set bit indicates that the corresponding interrupt is pending. The interrupt bit is cleared

when processing transfers to the corresponding interrupt vector.

Bit Mnemonic Interrupt Description

J1850RX J1850 Receive (LB only) J1850TX J1850 Transmit (LB only) AD A/D Conversion Complete (LA, LB) EP A0 EPA Capture/Compare Channel 0 EP A1 EPA Capture/Compare Channel 1 EP A2 EPA Capture/Compare Channel 2 EP A3 EPA Capture/Compare Channel 3

††

EPA

††

EPA 6–9 capture/compare channel events, EPA 0–1 compare channel events

Shared EPA Interrupt

†††

, EPA

0–3 and 8–9 capture/compare overruns, and timer overflows can generate this shared interrupt. Write the EPA mask registersto enable the interrupt sources; read the EPA pending registers to determine which source caused the interrupt.

†††

87C196LA, LB only.

†

Bits 6–7 are reserved on the 87C196LA, and bits 5–7 are reserved on the 83C196LD. For compatibility with future devices, write zeros to these bits.

Figure 4-3. Interrupt Pending (INT_PEND) Register

4-5

8XC196LX SUPPLEMENT

INT_PEND1

7 0

LA, LD

Bit

Number

†

7:0

†

Bit 5 is reserved on the 8XC196Lx devices and bit 0 is reserved on the 87C196LA and 83C196LD. For compatibility with future devices, always write zeros to these bits.

NMI EXTINT — RI TI SSIO1 SSIO0 J1850ST

7 0

NMI EXTINT — RI TI SSIO1 SSIO0 —

Function

Any set bit indicates that the corresponding interrupt is pending. The interrupt bit is cleared when processing transfers to the corresponding interrupt vector.

Bit Mnemonic Interrupt Description

NMI Nonmaskable Interrupt EXTINT EXTINT Pin Reserved —

RI SIO Receive TI SIO Transmit SSIO1 SSIO 1 Transfer SSIO0 SSIO 0 Transfer J1850ST J1850 Status (LB only)

Address:

Reset State:

0012H

00H

Figure 4-4. Interrupt Pending 1 (INT_PEND1) Register

4.2.3 Peripheral Transaction Server Registers

Figures 4-5 and 4-6 illustrate the PTS interrupt select and service registers for the 8XC196Lx microcontrollers.

4-6

STANDARD AND PTS INTERRUPTS

PTSSEL

Address:

Reset State:

0004H 0000H

The PTS select (PTSSEL) register selects either a PTS microcode routine or a standard interrupt service routine for each interrupt request. Setting a bit selects a PTS microcode routine; clearing a bit selects a standard interrupt service routine. In PTS modes that use the PTSCOUNT register, hardware clears the corresponding PTSSEL bit when PTSCOUNT reaches zero. The end-of-PTS interrupt service routine must reset the PTSSEL bit to re-enable the PTS channel.

15 8

— EXTINT — RI TI SSIO1 SSIO0

—

7 0

— — AD EPA0 EPA1 EPA2 EPA3 EPA

15 8

— EXTINT — RI TI SSIO1 SSIO0

J1850ST

7 0

J1850RX J1850TX AD EPA0 EPA1 EPA2 EPA3 EPA

15 8

— EXTINT — RI TI SSIO1 SSIO0 —

7 0

— — — EPA0 EPA1 EPA2 EPA3 EPA

Bit

Number

†

14:0

Setting a bit causes the corresponding interrupt to be handled by a PTS microcode routine.

Function

The PTS interrupt vector locations are as follows:

Bit Mnemonic Interrupt PTS Vector

EXTINT EXTINT pin 205 CH Reserved

†

— 205AH RI SIO Receive 2058H TI SIO Transmit 2056H SSIO1 SSIO 1 Transfer 2054H SSIO0 SSIO 0 Transfer 2052H J1850ST (LB) J1850 Status 2050H J1850RX(LB) J1850 Receive 204EH J1850TX(LB) J1850 Transmit 204CH AD(LA, LB) A/D Conversion Complete 204AH EP A0 EPA Capture/Compare Channel 0 2048H EP A1 EPA Capture/Compare Channel 1 2046H EP A2 EPA Capture/Compare Channel 2 2044H EP A3 EPA Capture/Compare Channel 3 2042H

††

EPA

††

PTS service is not useful for shared interrupts because the PTS cannot readily

Multiplexed EPA 2040H

determine the source of these interrupts.

†

Bit 13 is reserved on the 8XC196Lx devices and bits 6–8 are reserved on the 87C196LA and

83C196LD. For compatibility with future devices, write zeros to these bits.

Figure 4-5. PTS Select (PTSSEL) Register

4-7

8XC196LX SUPPLEMENT

PTSSRV

Address:

Reset State:

0006H 0000H

The PTS service (PTSSRV) register is used by the hardware to indicate that the final PTS interrupt has been serviced by the PTS routine. When PTSCOUNT reaches zero, hardware clears the corresponding PTSSEL bit and sets the PTSSRV bit, which requests the end-of-PTS interrupt. When the end-of-PTS interrupt is called, hardware clears the PTSSRV bit. The end-of-PTS interrupt service routine must set the PTSSEL bit to re-enable the PTS channel.

15 8

— EXTINT — RI TI SSIO1 SSIO0

—

7 0

— — AD EPA0 EPA1 EPA2 EPA3 EPA

15 8

— EXTINT — RI TI SSIO1 SSIO0

J1850ST

7 0

J1850RX J1850TX AD EPA0 EPA1 EPA2 EPA3 EPA

15 8

— EXTINT — RI TI SSIO1 SSIO0 —

7 0

— — — EPA0 EPA1 EPA2 EPA3 EPA

Bits Function

14:0

†

A bit is set by hardware to request an end-of-PTS interrupt for the corresponding interrupt through its standard interrupt vector.

The standard interrupt vector locations are as follows:

Bit Mnemonic Interrupt Standard Vector

EXTINT EXTINT pin 203 CH Reserved

†

— 203AH RI SIO Receive 2038H TI SIO Transmit 2036H SSIO1 SSIO 1 Transfer 2034H SSIO0 SSIO 0 Transfer 2032H J1850ST (LB) J1850 Status 2030H J1850RX (LB) J1850 Receive 202EH J1850TX (LB) J1850 Transmit 202CH AD (LA, LB) A/D Conversion Complete 202AH EP A0 EPA Capture/Compare Channel 0 2028H EP A1 EPA Capture/Compare Channel 1 2026H EP A2 EPA Capture/Compare Channel 2 2024H EP A3 EPA Capture/Compare Channel 3 2022H

††

EPA

††

PTS service is not useful for shared interrupts because the PTS cannot readily

Multiplexed EPA 2020H

determine the source of these interrupts.

†

Bit 13 is reserved on the 8XC196Lx devices and bits 6–8 are reserved on the 87C196LA and

83C196LD. For compatibility with future devices, write zeros to these bits.

Figure 4-6. PTS Service (PTSSRV) Register

4-8

I/O Ports

CHAPTER 5

I/O PORTS

The I/O ports of the 8XC196 Lx are functionall y identical to those of the 8XC196J x. However , o n the 87C196LA and LB, the reset state level of all 41 general-purpose I/O pins has changed from

a weak logic “1” (wk1) to a weak logic “0” (wk0). This chapter outlines the diff erences between the 87C196LA, LB and the 8XC196Kx controllers.

5.1 I/O PORTS OVERVIEW

Table 5-1 provides an overview of the 8XC196Lx and 8XC196Kx I/O ports.

Table 5-1. Microcontroller Ports

Port Pins Type

)

Port 0

Port 1

Port 2

Port 3 8 Memory mapped

Port 4 8 Memory mapped

Port 5

Port 6

8 (K 6 (CA, J

)

8 (K 4 (CA, J

)

8 (K 6 (CA, J

)

8 (K 3 (CA, J

)

8 (K 6 (CA, J

x, Lx

Standard Input-only

)

Standard

)

Standard

)

Memory mapped

)

Standard

)

Configuration

Options

Complementary Open-drain

Associated Peripheral or

System Function

A/D converter (not supported on LD)

EPA and timers J1850 (LB only), SIO,

interrupts, bus control, clock gen.

Address/data bus

Bus control, slave port

EPA, SSIO

5.2 INTERNAL STRUCTURE FOR PORTS 1, 2, 5, AND 6 (BIDIRECTIONAL PORTS)

Figure 5-1 shows the logic for driving the output transistors, Q1 and Q2. Consult the datasheet for specifications on the amount of current that each port can source or sink.

In I/O mode (selected by clearing a port mode register bit), the port data output and the port direction registers are input to the multiplexers. These signals combine to drive the gates of Q1 and Q2 so that the output is high, low, or high impedance.

In special-function mode (selected by setting a port mode register bit), SFDIR and SFDATA are input to the multiplexers. These signals combine to drive the gates of Q1 and Q2 so that the output is high, low, or high impedance. Special-function output signals clear SFDIR; special-function

5-1

8XC196LX SUPPLEMENT

input signals set SFD IR. Even if a pi n is to be u sed in special-func tion m ode, you must s till in itialize the pin as an input or output by writing to the port direction register.

Resistor R1 provides ESD protection for the pin. Input signals are buffered. The standard ports use Schmitt-triggered buffers for improved noise immu nity. Port 5 uses a standa rd input buffer because of the high speeds required for bu s control functions. The signals are latched into the port pin register sample latch and output onto the internal bus when the port pin register is read.

The falling edge of RESET# turns on transistor Q3, which remains on for about 300 ns, causing the pin to change rapidly to its reset state. The active-low level of RESET# turns on transistor Q4, which weakly holds the pin low . Q4 remains on, weakly holding the pin low, until your software writes to the port mode register.

NOTE

P2.7 is an exception. After reset, P2.7 carries the CLKOUT signal (half the crystal input frequency) rather than being held low. When CLKOUT is selected, it is always a complementary output.

5-2

I/O PORTS

Internal Bus

Px_REG

SFDATA

Px_DRV

SFDIR

Px_MODE

Read Port

0 1

Sample

Latch

Px_PIN

PH1 Clock

I/O Pin

RESET#

Buffer

150Ω to 200Ω

Medium Pullup

Weak Pullup

A5265-01

RESET#

300ns Delay

RESET#

Any Write to Px_MODE

Figure 5-1. Ports 1, 2, 5, and 6 Internal Structure (87C196LA, LB Only)

5.2.1 Configuring Ports 1, 2, 5, and 6 (Bidirectional Ports)

Using the port mode register, you can individually configure each pin for port 1, 2, 5, and 6 to operate either as a general-purpose I/O signal (I/O mode) or as a special-fu nction sig nal (specialfunction mode). In either mode, three configurations are possible: complementary output, high-

5-3

8XC196LX SUPPLEMENT

impedance input, or open-drain output. The p ort direction an d data outpu t registers sel ect the configuration for each pin. Complementary output means that the microcontroller drives the signal high or low. High-impedance input means that the microcontroller floats the signal. Open-drain output means that the microcontroller driv es the signal low or floats it. For I/O mode, the port data output register determines whether the microcontroller drives the signal hi gh, drives it low, or floats it. For special-function mode, the on-chip peripheral or system function determines whether the microcontroller drives the signal high or low for complementary outputs.

The pins for por ts 1, 2, 5, and 6 are weakly pulled low during an d after reset. Initializi ng t he pi n s by writing to the port mode register turns off the weak pull-downs. To ensure that the ports are initialized correctly, follow this suggested initialization sequence:

1. Write to Px_DIR to configure the individual pins. Clearing a bit configures a pin as a complementary output. Setting a bit configures a pin as a high-impedance input or opendrain output.

2. Write to Px_MODE to select either I/O or special-function mode. Writing to Px_MODE (regardless of the value written) turns off the weak pull-downs. Even if the entire port is to be used as I/O (its default configuration after reset), you must write to P x_MODE to ensure that the weak pull-downs are turned off.

3. Write to Px_REG.

For complementary output configurations:

In I/O mode, write the data that is to be driven by the pins to the corresponding Px_REG bits. In special-function mode, the value is immaterial because the on-chip peripheral or system function controls the pin. However, you must still write to Px_REG to initialize the pin.

For high-impedance input or open-drain output configurations: In I/O mode, write to Px_REG to either float the pin, making it available as a high impedance input, or pull it low. Setting the corresponding Px_REG bit floats the pin; clearing the corresponding Px_REG bit pulls the pin low. In special-function mode, if the on-chip peripheral uses the pin as an input signa l, you must set the cor responding P x_REG bit so that the pin can be driven externally. If the on-chip peripheral uses the pin as an output signal, the value of the corresponding Px_REG bit is immaterial because the onchip peripheral or system function controls the pin. However, you must still write to Px_REG to initialize the pin.

5.2.2 Special Bidirectional Port Considerations

This section outlines special cons ideration for using the pins of port s 1, 2, 5, and 6.

1. After reset, your software must configure the device to match the external system. This accomplished by writing appropriate configuration data into Px_MODE. Writing to Px_MODE not only configures the pins but also turns off the transistor that weak ly holds the pins low. For this reason, even if your port is to be used as it is configured at reset, you should still write data into Px_MODE.

2. P2.6/TXJ1850 is the enable pin for ONCE mode. Because a high input during reset can cause the device to enter ONCE mode or a reserved test mode, caution must be exercised

5-4

I/O PORTS

in using this pin. Be certain that your syst em meets the VIH specifications during reset to prevent inadvertent entry into ONCE mode or a test mode.

3. Following reset, P2.7/CLKOUT carries the strongly drive n CLKOUT signal. It is not held low. When P2.7/CLKOUT is configured as CLKOUT, it is always a complementary output.

5.3 INTERNAL STRUCTURE FOR PORTS 3 AND 4 (ADDRESS/DATA BUS)

Figure 5-2 shows the logic of ports 3 and 4. Consult the datas heet for specifications o n the amount of current ports 3 and 4 can source and sink.

During reset, the active-low level of RESET# tu rns off Q1 and Q2 and turns on transistor Q4, which weakly holds the pin low. Resistor R1 provides ESD protection for the pin. During normal operation, the device controls the port through BUS CONTROL SELECT , an internal control signal.

When the device needs to acces s external memor y, it clears BUS CONTROL SELECT , selecting ADDRESS/DATA as the input to the multiplexer. ADDRESS/DATA then drives Q1 and Q2 as complementary outputs.

When external memory access is not required, the device sets BUS CONTROL SELECT, selecting Px_REG as the input to the multiplexer. Px_REG then drives Q1 and Q2. If P34_DRV is set, Q1 and Q2 are driven as complementary outputs. If P34_DRV is cleared, Q1 is disabled and Q2 is driven as an open-drain output requiring an external pull-up resistor. With the open-drain configuration (BUS CONTROL SELECT set and P34_DRV cleared) and Px_REG set, the pin can be used as an input. The signal on the pin is latched in the Px_PIN register . The pins can be read, making it easy to see which pins are driven low by the device and which are driven high by external drivers while in open-drain mode.

5-5

8XC196LX SUPPLEMENT

Internal Bus

Px_REG

Address/Data

Bus Control Select

0 = Address/Data

1 = I/O

P34_DRV

Read Port

1 0

Sample

Latch

Px_PIN

PH1 Clock

I/O Pin

RESET#

150Ω to 200Ω

Buffer

Medium

300ns Delay

RESET#

Pullup

Weak Pullup

Figure 5-2. Ports 3 and 4 Internal Structure (87C196LA, LB Only)

A5264-01

5-6

Synchronous Serial I/O Port

CHAPTER 6

SYNCHRONOUS SERIAL I/O PORT

6.1 SSIO 0 CLOCK REGISTER

The SSIO 0 clock (SSIO_CLK) register selects the phase and polarity for the SC0 clock signal.

In standard mode, SC0 is channel 0’s clock signal. In duplex and channel-select modes, SC0 is the common clock signal for both SSIO channels.

SSIO0_CLK

The SSIO 0 clock (SSIO0_CLK) register configures the serial clock for channel 0. In standard mode,

the SC0 is channel 0’s clock signal. In duplex and channel-select modes, SC0 is the common clock signal for both SSIO channels.

7 0

— — — — — — PHAS POLS

Bit

Number

7:2 — Reserved; for compatibility with future devices, write zeros to these bits. 1 PHAS Phase and Polarity Select 0POLS

Bit

Mnemonic

Function

For normal transfers, these bits determine the idle state of the serial clock and select the serial clock signal edge on which the SSIO samples incoming data bits or shifts out outgoing data bits. These bits are ignored for handshaking transfers. Use SSIO0_ CON to select the type of data transfer (normal or handshaking) for channel 0.

For transmissions

PHAS POLS 0 0 low idle state; shift on falling edges 0 1 high idle state; shift on rising edges 1 0 low idle state; shift on rising edges 1 1 high idle state; shift on falling edges

For receptions

PHAS POLS 0 0 low idle state; sample on rising edges 0 1 high idle state; sample on falling edges 1 0 low idle state; sample on falling edges 1 1 high idle state; sample on rising edges

Address:

Reset State:

1FB5H

00H

Figure 6-1. SSIO 0 Clock (SSIO0_CLK) Register

6-1

8XC196LX SUPPLEMENT

For transmissions, SSIO0_CLK determines whether the SSIO shifts out data bits on rising or falling clock edges. For receptions, SSIO0_CLK determines whether the SSIO samples data bits on rising or falling clock edges.

6.2 SSIO 1 CLOCK REGISTER

SSIO1_CLK selects the SSIO mode of operation (standard, duplex, or channel-select), enables the channel-select master contention interrupt request, and selects the phase and polarity for the serial clock (SC1) for channels. In standard mode, use this register to configure the serial clock for channel 1.

SSIO1_CLK

The SSIO 1 clock (SSIO1_CLK) register selects the SSIO mode of operation (standard, duplex, or channel-select), enables the channel-select master contention interrupt request, and selects the phase and polarity for the serial clock (SC1) for channel 1.

7 0

— — CHS DUP CONINT CONPND PHAS POLS

Bit

Number

7:6 — Reserved; for compatibility with future devices, write zeros to these bits. 5 CHS These bits determine the SSIO operating mode. 4 DUP

3 CONINT Master Contention Interrupt

Bit

Mnemonic

Function

CHS DUP

0 0 standard mode 0 1 duplex mode 1 0 channel-s elect half-duplex mode (uses SD1 only) 1 1 channel-s elect full-duplex mode (uses both SD0 and SD1)

For channel-select master operations, the SSIO sets the master contention interrupt pending bit (CONPND) when the CHS# pin is externally activated. In a system with multiple masters, an external master activates the CHS# signal to request control of the serial clock.

CONINT determines whether the SSIO sets both CONPND and the SSIO0 interrupt pending bit or only CONPND when the CHS# pin is externally activated.

0 = SSIO sets only CONPND 1 = SSIO sets both CONPND and the SSIO0 interrupt pending bit

This bit is valid for channel-select master operations and ignored for all other operations.

Address:

Reset State:

1FB7H

00H

Figure 6-2. SSIO 1 Clock (SSIO1_CLK) Register

6-2

SYNCHRONOUS SERIAL I/O PORT

SSIO1_CLK (Continued)

7 0

— — CHS DUP CONINT CONPND PHAS POLS

Bit

Number

2 CONPND Master Contention Interrupt Pending

1 PHAS Phase and Polarity Select 0POLS

Bit

Mnemonic

Function

For channel-select master operations, the SSIO sets this bit when the CHS# pin is externally activated. In a system with multiple masters, an external master activates the CHS# signal to request control of the serial clock.

This bit is valid for channel-select master operations and ignored for all other operations.

For normal transfers, these bits determine the idle state of the serial clock and select the serial clock signal edge that the SSIO samples incoming data bits or shifts out outgoing data bits.

For transmissions

PHAS POLS 0 0 low idle state; shift on falling edges 0 1 high idle state; shift on rising edges 1 0 low idle state; shift on rising edges 1 1 high idle state; shift on falling edges

For receptions

PHAS POLS 0 0 low idle state; sample on rising edges 0 1 high idle state; sample on falling edges 1 0 low idle state; sample on falling edges 1 1 high idle state; sample on rising edges

These bits are ignored for duplex and channel-select modes; these modes use SC0 as the common clock signal. The SSIO0_CLK register contains the phase and polarity select bits for the SC0 clock signal.

These bits are also ignored for handshaking transfers. Use SSIO1_ CON to select the type of data transfer (normal or handshaking) for channel 1.

Address:

Reset State:

1FB7H

00H

Figure 6-2. SSIO 1 Clock (SSIO1_CLK) Register (Continued)

For transmissions, SSIO1_CLK determines whether the SSIO shifts out data bits on rising or falling clock edges. For receptions, SSIO1_CLK determines whether the SSIO samples data bits on the rising or falling clock edges.

6-3

Event Processor Array

CHAPTER 7

EVENT PROCESSOR ARRAY

The EPA on the 8XC196Lx is functionally identical to that of the 8XC196Jx; however, the 8XC196Lx has only two capture/compare channels without pins instead of four. In addition, the 83C196LD has no compare-only channels.

7.1 EPA FUNCTIONAL OVERVIEW

Table 7-1 lists the capture/compare (with and without pins) and compare-only channels for each device in the 8XC196Lx and 8XC196Kx families.

Table 7-1. EPA Channels

Device

8XC196LA, LB EPA3:0 and EPA9:8 EPA7:6 COMP1:0 8XC196LD EPA3:0 and EPA9:8 EPA7:6 —

87C196CA, 8XC196J 8XC196K

Capture/Compare

Channels With Pins

EPA3:0 and EPA9:8 EPA7:4 COMP1:0

EPA9:0 — COMP1:0

Capture/Compare

Channels Without Pins

Compare-only

Channels

The 8XC196Lx’s EPA performs input and output functions associated with two timer/counters, timer 1 and timer 2, as depicted in Figures 7-1 and 7-2.

7-1

8XC196LX SUPPLEMENT

Timer-Counter Unit

TIMER1

TIMER2

EPA 3:0

EPA8 / COMP0

EPA9 / COMP1

Capture/Compare

Channel 0–3

Capture/Compare

Channel 6–7

Capture/Compare

Channel 8

Compare-only

Channel 0

Capture/Compare

Channel 9

Compare-only

Channel 1

EPA 3:0 Interrupts

Indirect

Interrupt

Processor

Logic

Figure 7-1. EPA Block Diagram (87C196LA, LB Only)

EPA

Interrupt

A5269-01

7-2

Timer-Counter Unit

TIMER1

TIMER2

EVENT PROCESSOR ARRAY

EPA 3:0

EPA8

EPA9

Capture/Compare

Channel 0–3

Capture/Compare

Channel 6–7

Capture/Compare

Channel 8

Capture/Compare

Channel 9

EPA 3:0 Interrupts

Indirect

Interrupt

Processor

Logic

Figure 7-2. EPA Block Diagram (83C196LD Only)

EPA

Interrupt

A5281-01

7-3

8XC196LX SUPPLEMENT

7.1.1 EPA Mask Registers

Figures 7-3 and 7-4 illustrate t he EPA m ask registers, EPA_MASK and EPA_MASK1, for the 8XC196Lx microcontroller family.

EPA_MASK

The EPA interrupt mask (EPA_MASK) register enables or disables (masks) interrupts associated with

the shared EPA

Bit

Number

†

15:0

†

Bits 2–5 and 14–15 are reserved on the 8XC196Lx device family. For compatibility with future devices, write zeros to these bits.

interrupt.

15 8

— — EPA6 EPA7 EPA8 EPA9 OVR0 OVR1

7 0

0VR2 OVR3 — — — — OVR8 OVR9

Function

Setting a bit enables the corresponding interrupt as a EPAx interrupt source. The shared

interrupt is enabled by setting its interrupt enable bit in the interrupt mask register

EPA (INT_MASK.0 = 1).

Address:

Reset State:

1FA0H

0000H

Figure 7-3. EPA Interrupt Mask (EPA_MASK) Register

EPA_MASK1

Address:

Reset State:

1FA4H

00H

The EP A interrupt mask 1 (EPA_MASK1) register enables or disables (masks) interrupts associated

with the multiplexed EPA

7 0

— — — — COM P0

Bit

Number

7:4 Reserved; for compatibility with future devices, write zeros to these bits. 3:0

†

Setting a bit enables the corresponding interrupt as a multiplexed EPAx interrupt source. The multiplexed EPA interrupt mask register (INT_MASK.0 = 1).

†

87C196LA, LB only; reserved on 83C196LD.

interrupt.

†

COMP1†OVRTM1 OVRTM2

Function

interrupt is enabled by setting its interrupt enable bit in the

Figure 7-4. EPA Interrupt Mask 1 (EPA_MASK1) Register

7-4

EVENT PROCESSOR ARRAY

7.1.2 EPA Pending Registers

Figures 7-5 and 7-6 illustrate the EPA pending registers, EPA_PEND and EPA_PEND1, for the 8XC196Lx microcontroller family.

EPA_PEND

When hardware detects a pending EPA6–9 or OVR0–3, 8–9 interrupt request, it sets the corresponding bit in the EPA interrupt pending register (EPA_PEND or EPA_P END1) . The EPAIPV register contains a number that identifies the highest priority, active, shared interrupt source. When EPAIPV is read, the EPA interrupt pending bit associated with the EPAIPV priority value is cleared.

15 8

Bit

Number

†

15:0

†

Bits 2–5 and 14–15 are reserved on the 8XC196Lx device family. For compatibility with future devices, write zeros to these bits.

Any set bit indicates that the corresponding EPAx interrupt source is pending. The bit is cleared when software reads the EPA interrupt priority vector register (EPAIPV).

— — EPA6 EPA7 EPA8 EPA9 OVR0 OVR1

7 0

0VR2 OVR3 — — — — OVR8 OVR9

Function

Address:

Reset State:

Figure 7-5. EPA Interrupt Pending (EPA_PEND) Register

EPA_PEND1

Address:

Reset State:

1FA6H

1FA2H

0000H

00H

When hardware detects a pending EPA pending register (EPA_PEND or EPA_PEND1). The EPAIPV register contains a number that identifies the highest priority , active, multiplexed interrupt source. When EPAIPV is read, the EPA interrupt pending bit associated with the EPAIPV priority value is cleared.

7 0

— — — — COM P0

Bit

Number

7:4 Reserved; always write as zeros. 3:0

†

Any set bit indicates that the corresponding EPAx interrupt source is pending. The bit is cleared when the EPA interrupt priority vector register (EPAIPV) is read.

†

87C196LA, LB only; reserved on 83C196LD.

interrupt, it sets the corresponding bit in the EPA interrupt

†

COMP1†OVRTM1 OVRTM2

Function

Figure 7-6. EPA Interrupt Pending 1 (EPA_PEND1) Register

7-5

8XC196LX SUPPLEMENT

7.1.3 EPA Interrupt Priority Vector Register

Figure 7-7 illustrates the EPA interrupt priority vector (EPAIPV) register for the 8XC1 96Lx microcontroller family.

EPAIPV

When an EPA that identifies the highest priority, active, multiplexed interrupt source (see Table 7-2).

EPAIPV allows software to branch via the TIJMP instruction to the correct interrupt service routine when EP A the value in EP AIPV. When all the EPA pending bits are cleared, the EPA

7 0

— — — PV4 PV3 PV2 PV1 PV0

Bit

Number

5:7 — Reserved; for compatibility with future devices, write zeros to these bits. 4:0 P V4:0 Priority Vector

interrupt occurs, the EP A interrupt priority vector (EPAIPV) register contains a number

is activated. Reading EPAIPV clears the EPA pending bit for the interrupt associated with

Bit

Mnemonic

These bits contain a number from 01H to 14H corresponding to the highest-priority active interrupt source. This value, when used with the TIJMP instruction, allows software to branch to the correct interrupt service routine.

Function

Address:

Reset State:

pending bit is also cleared.

1FA8H

00H

Figure 7-7. EPA Interrupt Priority Vector Register (EPAIPV)

Table 7-2. EPA Interrupt Priority Vectors

Value Interrupt Value Interrupt Value Interrupt

14H — 0DH OVR1 06H OVR8 13H — 0CH OVR2 05H OVR9 12H EPA6 0BH OVR3 04H COMP0

11H EPA7 0AH — 03H COMP1 10H EPA8 09H — 02H OVRTM1

0FH EPA9 08H — 01H OVRTM2 0EH OVR0 07H — 00H None

†

87C196LA, LB only; reserved on 83C196LD.

† †

7-6

J1850 Communications Controller

CHAPTER 8

J1850 COMMUNICATIONS CONTROLLER

The J1850 communications controller manages communications between multiple network nodes. This integrated peripheral supports the 10.4 Kb/s VPW (variable pulse width) mediumspeed class B in-vehicle network protocol. It also supports both the standard and in-frame response (IFR) message framing as specified by the Society of Automotive Engineering (SAE) J1850 (revised May 1994 ) technical st andards . Its lower cost p er node mak es it suitable for d iagnostics and non-real-time data sharing in applications with high numbers of nodes. This chapter details the integrated J1850 controller and explains how to configure it.

8.1 J1850 FUNCTIONAL OVERVIEW

The integrated J1850 communications controller transfers messages between network nodes according to the J1850 protocol. The complete J1850 communications protocol solution includes an on-chip, J1850 digital-logic controller working with an external analog bus transceiver circuit. Figure 8-1 illustrates the J1850 protoco l with the J1850 contro ller integrated on the 87C19 6LB 16-bit microcontroller and a standalone J1850 bus transceiver device. The example uses the Har- ris HIP7020 as the remote transceiver device.

Clock

TXJ1850

RXJ1850

87C196LB

Microcontroller

PLL/ CLKOUT

Figure 8-1. Integrated J1850 Communications Protocol Solution

HIP7020

The benefit of an integrated, J1850 protocol solution is threefold:

• Minimizes CPU overhead for reception and transmission of J1850 messages.

• Frees up serial and parallel communications ports for other purposes.

• Offers significant printed-circuit board area savings when compared with conventional

standalone protocol devices.

J1850 Bus

A5168-01

8-1

8XC196LX SUPPLEMENT

The J1850 controller can handle network protocol functions including message frame sequencing, bit arbitr atio n, in-frame r esp onse (I FR) messag ing, er ror det ection, an d delay compens atio n.

The J1850 communications controller (Figure 8-2) consists of a control state machine (CSM), symbol synchronization and timing (SST) circuitry, six control and status registers, transmit and receive buffers, and an interrupt handler.

J1850ST J1850RX

J1850TX

OVR

UNDR

Peripheral Data Bus

Interrupt

Handler

J_DLY

J_STAT

J_TX

JTX_BUF

JRX_BUF

J_RX

Bus Error RX

Error

Detection

Circuitry

Bit

Arbitration

Circuitry

Cyclic

Redundancy

Check Circuitry

J1850 Communications Controller

Delay

Symbol

Encoder

Symbol

Decoder

Prescaler

Compensator

Digital

Filter

TXJ1850

RXJ1850

Internal Clocking

8-2

J_CMD

J_CFG

CSM

Figure 8-2. J1850 Communications Controller Block Diagram

SST

A5169-01

J1850 COMMUNICATIONS CONTROLLER

8.2 J1850 CONTROLLER SIGNALS AND REGISTERS

Table 8-1 describes the J1850 con troller ’s pins, and Table 8-2 describes the control and status registers.

Table 8-1. J1850 Controller Signals

Signal Type Description

RXJ1850 I Receive

Carries digital symbols from a remote transceiver to the J1850 controller.

TXJ1850 O Transmit

Carries digital symbols from the J1850 controller to a remote transceiver.

Table 8-2. Control and Status Registers

Mnemonic Address Description

J_CFG 1F54H J1850 Configuration

Program this byte register to specify the oscillator prescaler divisor, mode of operation, and normalization bit format. You must write to this register during the initialization sequence.

J_CMD 1F51H J1850 Command

Program this byte register to specify the number of bytes to be transmitted in the next message frame. This register also monitors the status of the message transmission in progress, and it can abort, ignore, or retry a message if necessary. Read this register to determine the status of transmissions in progress.

J_DLY 1F58H J1850 Delay Compensation

Program this byte register to define the length of the delay time through the external transceiver to compensate for the inherent propagation delays and to accurately resolve bus contention during arbitration. You must write to this register during the initialization sequence.

J_RX 1F52H J1850 Receiver

Read this byte register to receive data in byte increments from the J1850 bus to the microcontroller CPU. This register is buffered to allow for reception of a second data byte while the first data byte is being read.

J_STAT 1F53H J1850 Status

Read this byte register to determine the current status of the receive and transmit buffers and the J1850 interrupt sources. You can also determine bus status and in-frame response messaging status. All bits of this register are cleared when read, with the exception of the BUS_STAT bit.

J_TX 1F50H J1850 Transmitter

Program this byte register to transmit data in byte increments to the J1850 bus from the microcontroller CPU. This register is buffered to allow for writing of a second data byte while the first data byte is being shifted out.

8-3

8XC196LX SUPPLEMENT

Table 8-2. Control and Status Registers (Continued)

Mnemonic Address Description

INT_MASK 0008H Interrupt Mask

Bits 6 and 7 in this register enable and disable the J1850 receive and transmit interrupt requests, respectively.

INT_MASK1 0013H Interrupt Mask 1

Bit 0 in this register enables and disables the J1850 bus error interrupt request.

INT_PEND 0009H Interrupt Pending

Bits 6 and 7 in this register, when set, indicate pending J1850 receive and transmit interrupt requests, respectively.

INT_PEND1 0012H Interrupt Pending 1

Bit 0 in this register, when set, indicates a pending J1850 bus error interrupt request.

PTSSEL 0004H PTS Select

Bits 6, 7, and 8 of this word register select either a PTS service request or a standard interrupt service request for J1850TX, J1850RX, and J1850ST interrupts, respectively.

PTSSRV 0006H PTS Service

Bits 6, 7, and 8 of this word register are set by hardware to request an end-of-PTS interrupt for the J1850.

8.3 J1850 CONTROLLER OPERATION

This section describes the control state machine (which contains the cyclic redundancy check generator) and the symbol syn chronization an d timing circu itry for J1850 transmissio ns and receptions.

8.3.1 Control State Machine

The control state machine (CSM) represents the engine of the digital circuitry portion of the J1850 communications controller. The CSM handles all message framing for standard and inframe response (IFR) messaging, data validation, bus contention, bit arbitration, and error detection.

8.3.1.1 Cyclic Redundancy Check Generator

The cyclic r edund ancy check (CR C) generator circuitry calculates and check s the CRC byte gen- erated for both transmitted and received standard messages as specified by SAE J1850 protocol specification for class B in-vehicle networks. The CRC calculation is a code byte of information that verifies the proper recep tion or transmission of your message. The calculated CRC co de byte is always appended as the last byte of your transmitted message. On reception , the calculated CRC checksum byte always results in a value of C4H f or valid messages. An invalid CRC checksum during reception signals the presence o f an er ror in yo ur in coming messag e, which im mediately sets the J1850 bus error (J1850BE) bit in the J_STAT register (Figure 8-19 on page 8-21).

8-4

J1850 COMMUNICATIONS CONTROLLER

8.3.1.2 Bus Contention

Bus contention arises when multiple nodes attempt to access and transmit message frames across the J1850 bus simultaneously. This creates a conflict on the bus. The recognition of conflicting symbols or bits on t h e bus i s ref erred to as contention detection. For example, if a node observes a difference between a symbol it transmits to the J1850 bus and the symbol that it detects on the bus, that node has detected contention to the transmission of its message frame. Only one message frame from one node vying for the bus wins arbitration on each symbol or bit of its frame. This winning message frame does not experience or detect contention. The message frames that were not awarded arbitration will experience contentio n.

8.3.1.3 Bit Arbitration

A bit arbitrat ion scheme is used to resolve such conflicts as bus contention. The J1850 protocol uses the carrier sense multiple access (CSMA) bit arbitration scheme. Bit arbi tration is the process of settling conflicts that occur when multiple nodes attempt to transmit one bit or symbol at a time across a single bus. A symbol is simply a timing-level formatted bit. By definition, a node that detects contention has lost arbitration and will discontinue t ransm itting any further symbols remaining in its message frame. Remain ing nodes vying for the bus will con tinue to send their symbols until the ne xt instance o f contentio n is detected or arbitration is awarded. This process continues until a complete message frame from one node has been transmitted. For details on this arbitration scheme, refer to the “Bit Arbitration Example” on page 8-7.

8.3.1.4 Error Detection

The J1850 controller’s error detection logic monitors the bus for four error conditions, and sets the J1850BE interrupt pending bit in the J_STAT register if an error occurs. The following list describes each error type:

• CRC error — the calculated CRC checksum received on incoming messages has a value

other than C4H (the expected value for all received message frames).

• bus symbol timing error — the symbol stream on the J1850 bus contains an invalid symbol.

An invalid symbol is any signal that is between 8 µs and 34 µs in duration.

• incomplete byte error — an EOD/EOF symbol occurred,but was not on a byte boundary;

the number of bits recieved was not a multiple of eight .

• no echo — the message is tran sm itted; however, the transmission’s echo back through the

feedback loop to the receiver has not been detected within the allowable 60 µs window.

8.3.2 Symbol Synchronization and Timing Circuitry

The symbol synchronizati on and timing (SST) circuitr y consists of a clock prescaler , digital filter , delay compensatio n circu itry, and s ynch ron i zati o n and sy mbol en codi n g/ deco di ng circuitry . The SST supports Huntzicker encoding of symbols, which entails 10.4 Kb/s variable pulse-width (VPW) operation for valid edge detection on message receptions.

8-5

8XC196LX SUPPLEMENT

8.3.2.1 Clock Prescaler

Because the 87C196LB microcontroller can operate at a var iety of input frequencies (F

XTAL

), the

clock prescaler circuitry is used to provide a single, internal clock frequency (f/2) to ensure that the J1850 peripheral is clocked at the proper operating frequency. This is accomplished through the programmable clock prescaler bits, PRE1:0 in the J_C FG register (Figure 8-17 on page 8-18). The prescale bits support input frequencies of 8, 12, 16, and 20 MHz on the XTAL1 pin. With the phase-locked loop (P LL) circuitry enabled, the prescale bits can su ppo rt inpu t frequencies of 4, 6, 8, and 10 MHz on the XTAL1 pin.

Table 8-3 details the relationships between the input frequency, the configuration of PLL, the internal clock frequency, and the prescaler bits.

Table 8-3. Relationships Between Input Frequency, PLL, and Prescaler Bits

XTAL1

PLL

Disabled

8 MHz 4 MHz 4 MHz 0 0 12 MHz 6 MHz 6 MHz 0 1 16 MHz 8 MHz 8 MHz 1 0 20 MHz 10 MHz 10 MH z 1 1

8.3.2.2 Digital Filter

PLL

Enabled

Internal Clock Frequency

(f/2)

PRE1 PRE0

To automatically r e ject noise spikes of 8 µs or less in duration, the J1850 control l er u ses a digital filter between the RXJ1850 input pin and the symbol synchronization logic.

A noise spike is defined as an active or passive state pulse that is shorter in duration than a valid receive symbol at that state. A valid receive symbol is at least 34 µs in duration. Any symbo l captured on the bus between 8 µs and 34 µs in duration is considered invalid and is flagged by the J_STAT register as a bus-symbol timing error.

8.3.2.3 Delay Compensation

Because the digital portion of the J1850 protocol is integrated onto the microcontroller and physically separated from the transceiver and J1850 bus, control over critical timing parameters of various manufacturers’ remote transceivers is required. The delay compensation circuitry addresses this requirement by providin g the flexibility to compensate for propagation delay and pulse-width variations among various transceivers. The compensation circuitry synchronizes itself to the leading edge of each input symbol , which allows for accurate detection of bus contention during bit arbitration. The delay compens ati o n is pr ogr ammabl e t hro ugh the J_DLY register (Figure 8-18 on page 8-20).

8.3.2.4 Symbol Encoding and Decoding

The J1850 protocol supports the Huntzicker encoding method, which is based on variable pulsewidth (VPW) bus modul ation. VPW modu lation is a forced hi gh/low symbol t ransition format ting

scheme that tracks the duration between two consecutive transitions and the level of the bus, active or passive (Figure 8-3).

8-6

J1850 COMMUNICATIONS CONTROLLER

1 0

128µS

"passive 1"

64µS

"passive 0"

1 0

64µS

"active 1"

128µS

"active 0"

A5219-01

Figure 8-3. Huntzicker Symbol Definition for J1850

A symbol is defined as a timing-level formatted bit. The VPW symbol timing requirements stipulate that there is one symbol per transition and one transition per symbol. This ensures that a message frame will always result in a uniform squ a re waveform of varying level durations. Figure 8-4 depicts a typical Huntzicker formatted data byte of hex value CCH.

"1"

"0"

"1""0"

"1"

"0"

B4 B3

A5222-01

Figure 8-4. Typical VPW Waveform

Bits 7 and 3 carry logic level 1 data; however, they are represented by a passive-level symbol in keeping with the VPW requirements. Bits 4 and 0 carry logic level 0 data and are represented by an active-level symbol.

8.3.3 Bit Arbitration Example

The drive capacity of each symbol establishes the priority for arbitration. By d efinition, an active bus level is a driven state, and a passive bus level is a non-driven, or idle, state. A driven b us state

is always given priority over an idle bus in arbitration. An “active 0” state has priority over an “active 1” state in arbitration, because the “active 0” state is driven over a longer duration, 128 µs versus the “active 1” state’s drive time of 64 µs. Similarly, a “passive 0” state has priority over a “passive 1” state, because the “passive 0” state comes out of its idle state in a shorter period of time, 64 µs versus the “passive 1” state’s idle time of 128 µs.

For example, Figure 8-5 illustrates four nodes v ying for the bus. Node B is th e first no de to discontinue transmitting when it attempts to transmit a “passive 1” symbol onto the bus. At the point

8-7

8XC196LX SUPPLEMENT

of arbitration, nodes A, C, and D are all transmitting an “active 0” symbol, thus the idle state of the “passive 1” symbol is overruled in favor of the driven state of the “active 0” symbol.

Node C is the next node to discontinue transmitting when it attempts to take control of the bus by transmitting an “active 1” symbol. However, nodes A and D maintain control by continuing to drive the bus with an “active 0” symbol.

Finally , node D discontinues transmitting when its attempt to hold the bus in an idle state is overruled by the driven state of the “active 1” symbol on no de A. Thus, node A is awarded arbitration.

The busline signal, detected on the bus by the receiver, reflects node A’s message, as this is the only node that did not experience contention.

Node A

Node B

Node C

Node D

Busline

"0" "0" "0" "1""0" "1""0""0"

"0" "0"

"0" "0" "0" "1""0" "1"

"0" "0" "0" "1""0" "1""0"

"1"

Point of Arbitration

8.4 MESSAGE FRAMES

A message transmission or reception is transferred within a message frame that adds control and error-detection bits to the content of the message. The frame for an IFR message differs slightly from that for a standard message, but they contain similar information (Figure 8-6).

8-8

A5223-01

Figure 8-5. Bit Arbitration Example

J1850 COMMUNICATIONS CONTROLLER

Standard Frame

In-frame Response (IFR) Frame

†

1-3 Bytes

Header

1-3 Bytes

Header

The number of data bytes to be transferred is unspecified if 0EH is written to J_CMD3:0.

1-11 Bytes

†

Data

1-11 Bytes

†

Data

1 Byte

CRC

1 Byte

CRC

1-32 Bytes

IFR Data

0-1 Byte

CRC

E O D

A5225-01

Figure 8-6. J1850 Message Frames

A standard message frame is initiated by the responder and contain s no more than 11 data bytes to be transmitted. An IFR message is a request initiating the recipient(s) to respond by transmitting data within the same frame. The following subsections describe each of the messaging forms.

8.4.1 Standard Messaging

A standard message frame can best be described as a “send mode only” format that is initiated by the responder either to request inf ormation o r to reply to a r eceived message from a remote no de. In addition to the actual data that is being transmitted, the standard message is composed of a header (1–3 bytes), a CRC byte, and a series of start and end symbols.

8.4.1.1 Header

The header provides general infor mation o n the p hy sical network an d the n ecessary interface requirements. For a complete description of the header, refer to the Society of Automotive Engineer- ing (SAE) J1850 specifications (revised May 1994).

8.4.1.2 CRC Byte

The CRC byte, calculated through the cyclic redundancy check generator, is a checksum value that verifies the accuracy of the data message transmitted onto the bus. The CRC byte is appended to all data messages and optionally appended to IFR response messages. Upon reception, the CRC byte is compared with the value C4H. If the values match, the transmitted message is valid; otherwise, it is invalid, and an error flag in the J_STAT register is set.

8.4.1.3 Normalization Bit

The normalization bit (NB), found only in IFR messaging, defines the start of the IFR message response data. The NB is tr iggered by bit J_CMD. 6 and is transmitted aft er an end-of-data (EOD) symbol is detected on the bus. The timing format of the NB is assigned by the J_CFG register

8-9

8XC196LX SUPPLEMENT

(J_CFG.7) and considers whether the IFR message response has a CRC byte appended. Figure 8-7 depicts th e SAE preferred, active-level state bit format timing for the NB.

1 0

NB for IFR without CRC

Figure 8-7. Huntzicker Symbol Definition for the Normalization Bit

8.4.1.4 Start and End Message Frame Symbols

64µS

1 0

128µS

NB for IFR with CRC

A5220-01

Five symbols are used to mark the start and end of a message frame and to allow the J1850 bus to properly recognize the interruption of a message transmission or reception. Figure 8-8 illustrates the formats and their respective timing.

The following is a description of each symbol:

• start of frame (SOF) — this symbol signals the start of a message frame. This is an active-

level state symbol only and appears once per frame.

• end of data (EOD) — this symbol signals the end of the data transmission. This is a passive-

level state symbol only. It appears twice in IFR messaging: at the end of the initial request data field and at the end of the IFR data field.

• end of frame (EOF) — this symbol signals the end of a message frame and returns the bus

to an idle state. This is a passive-level state symbol only. It appears once per frame.

• in-frame separation (IFS) — the timing of th is s ymbol allows for proper synchronization of

multiple nodes during back-to-back transmissions. Nodes contending for the bus must comply with one of two condit ions before transmitting:

— wait for the IFS minimum timing to expire — wait for a rising edge on the bus after the EOF minimum timing has expired

• break (BRK) — this symb ol signals an interruption during a bus transmission. At the point

of termination, all nodes are reset. This is an active-level state symbol.

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J1850 COMMUNICATIONS CONTROLLER

1 0

200µS

"Start of Frame (SOF)"

200µS "End of Data (EOD)"

280µS "End of Frame (EOF)"

300µS+

"In-frame Separation (IFS)"

768µS+

"Break Signal (BRK)"

A5221-01

Figure 8-8. Definition for Start and End of Frame Symbols

Table 8-4 details the symbol timing characteristics supported by the 87C196LB.

Table 8-4. Huntzicker Symbol Timing Characteristics

Name S ymbol Bus Level TTXmin TTXnom TTXmax TRXmin TRXmax Units

Logic Level 0 0

Logic Level 1 1 Start of Frame SOF Active 193 200 207 163 <239 µs

End of Data EOD Passive 193 200 207 163 <239 µs End of Frame EOF Passive 271 280 289 239 <300 µs In-frame Separation IFS Passive >300 — — >300 — µs Break BRK Active 768 — — >239 — µs NOTE: Timings are based on the standard bus rate of 10.4 Kb/s. When operating in 4x mode, the bus

rate becomes 41.6 Kb/s and all symbol timings are one fourth that shown.

Passive 60 64 68 34 <96 µs Active 122 128 134 96 <163 µs Passive 122 128 134 96 <163 µs Active 60 64 68 34 <96 µs

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8XC196LX SUPPLEMENT

8.4.2 In-frame Response Messaging

There are three types of in-frame response (IFR) message framings: type 1 (a single byte from a single responder), type 2 (a single byte from multiple responders), and type 3 (multiple bytes from a single responder). Like the standar d message frame, the IFR frame is compo sed of header , data, and CRC bytes, and a series of start and end symbols. Unlike the standard message frame, the actual length of the IFR message frame will differ based on the desired response.

Consider the following example: a system’s controller (the requ estor) requests an information update from each of four nodes (the responders) in the system. W ith type 1 messaging, the controller can receive a limited information update if it sends out four separate transmissions. With type 2 messaging, the controller can receive a limited information update b y sending one message. With type 3 messaging, the controller can receive unlimited information; however, it will require four separate transmissions. The following subsections detail this example for the three IFR messaging types.

8.4.2.1 IFR Messaging Type 1: Single Byte, Single Responder

No IFR messaging type carries a distinct advantage or disadvantage over the other messaging types. IFR messaging type 1 (Figure 8-9) is ideal for use when requesting small amounts of information from a single source in your system. In the above example, suppose you want to know how many pounds of pressure each of th e fou r remo te nod e sites experi enced af ter the con t roller sent out a request to each node sensor to exert a given am ount of pr essure. If you u se type 1 messaging, the controller will send four separate serial messages to the remote no de s ites in the system and wait for their responses. Keeping the data timing a constant, the CPU overhead of transmitting these messages alone amounts to a minimum of 4.96 ms (refer to Table 8-4 on page 8-11 for all symbol timings).

In-frame Response (IFR) Frame

S O F

†

The number of data bytes to be transferred is unspecified if 0EH is written to J_CMD3:0.

1-3 Bytes

Header

1-11 Bytes

†

Data

1 Byte

CRC

1Byte

IFR Data

0-1 Byte

CRC

A5229-01

Figure 8-9. IFR Type 1 Message Frame

8.4.2.2 IFR Messaging Type 2: Single Byte, Multiple Responders

When response time is the highest consideration, IFR messaging type 2 is desirable. IFR type 2 messaging can monitor up to 32 remote nodes on a given request (see Figure 8-10). While it allows only one byte of information per response, in many cases a single byte of information is more than adequate. In our example, suppose that each node sensor detected a pressure of 75 P.S.I. (pounds per square inch). The response (the value 75) would take a single byte, 46H, to communicate the reply. The maximum overhead required is 1.24 ms, or one fourth the time it would take type 1 messaging to achieve the same results.

8-12

J1850 COMMUNICATIONS CONTROLLER

††

0-1 Byte

CRC

O D

A5227-01

N B

IFR Data Field

. . . . . . . . . .

1D0

In-frame Response (IFR) Frame

† ††

1-3 Bytes

Header

The number of data bytes to be transferred is unspecified if 0EH is written to J_CMD3:0. Each D

block in the IFR data field represents a byte of data from a different remote node.

1-11 Bytes

†

Data

1 Byte

CRC

E O D

Figure 8-10. IFR Type 2 Message Frame

8.4.2.3 IFR Messaging Type 3: Multiple Bytes, Single Responder

IFR messaging type 3 (Figure 8-11) is ideal for requesting large amounts of information from a single source in your system. You can compile up to 12 bytes of data from a remote node on a single request. In our example, for the same amount of CPU overhead as IFR type 1 messaging exhausted (4.96 ms), you can gather up to twelve times as much information.

In-frame Response (IFR) Frame

1-3 Bytes

Header

1-11 Bytes

†

Data

1 Byte

CRC

1-12 Bytes

IFR Data

0-1 Byte

CRC

†

The number of data bytes to be transferred is unspecified if 0EH is written to J_CMD3:0.

A5228-01

Figure 8-11. IFR Type 3 Message Frame

8.5 TRANSMITTING AND RECEIVING MESSAGES

The J1850 controller can transmit and receive messages in either standard or IFR form.

8.5.1 Transmitting Messages

To transmit a standard message, prepare the message in register RAM and then write it to the J1850 transmit (J_TX) register (Figure 8-12) one byte at a time.

8-13

8XC196LX SUPPLEMENT

J_TX

The J1850 transmitter (J_TX) register transfers data in byte increments to the J1850 bus from the microcontroller CPU. This register is buffered to allow for transmission of a second data byte while the first data byte is being shifted out. This byte register can be read or written, and is addressable through

7 0

windowing

Address:

Reset State:

1F50H

00H

Transmit Byte

Bit

Number

7:0 DB7:0 Data Bits

Bit

Mnemonic

Function

These eight bits compose the data byte to be transmitted to the J1850 bus.

Figure 8-12. J1850 Transmitter (J_TX) Register

Transmitting the message requires that you first program the J1850 command (J_CMD) register to specify the number of bytes you want to transfer across the J1850 bus. The number of bytes specified must include the header byte(s). After the start of frame (SOF) symbol is put on the bus, the first header byte is transferred to J_TX for transmission. This byte will automatically be transferred into the J1850 transmit buffer (JTX_BUF) and the second byte of the message frame will be written to J_TX. The transfer of the first byte to JTX_BUF triggers t he transmissio n process and generates the J1850 transmi ssi on (J1 850TX) int errupt (if it is enab led), sign aling that J_TX is available for another byte (Figure 8-13).

CPU

J_TX

JTX_BUF

Message transmit interrupt (J1850TX) set

J1850 Bus

A5235-01

Figure 8-13. J1850 Transmit Message Structure

After the byte in JTX_BUF is transmitted, the byte residing in J_TX is automatically shifted into JTX_BUF, freeing J_TX for another byte. This pro cess con tinues until th e CSM has res olved t he number of message bytes (MSG3:0) programmed into the J_CMD register.

If the last message byte being transmitted is shifted out before the MSGx count expires, a J1850ST core interrupt is generated and the OVR_UNDR (J_STAT.3) bit records a transmitter underflow error in the J_STAT register.

8-14

J1850 COMMUNICATIONS CONTROLLER

NOTE

An overrun condition can occur on trans mission if the transmit buffer, JTX_BUF, is overwritten.

8.5.2 Receiving Messages

For a message reception, after a SOF is detected on the bus, the contro ller starts to shift data sy mbols into the J1850 receive buffer (JRX_BUF) until an entire data byte has been received. This byte is automatically transferred into th e J1850 receive (J_R X) register (Figure 8-14 ) and the subsequent byte is written into the empty JRX_BUF.

J_RX

The J1850 receiver (J_RX) register transfers received data in byte increments from the J1850 bus to the microcontroller CPU. This register is buffered to allow for reception of a second data byte while the first data byte is being read. This byte register can be read or written, and is addressable through

windowing

7 0

Address:

Reset State:

1F52H

00H

Receive Byte

Bit

Number

7:0 DB7:0 Data Bits

Bit

Mnemonic

Function

These eight bits compose the last data byte received from the J1850 bus.

Figure 8-14. J1850 Receiver (J_RX) Register

The transfer of the first byte to J_RX triggers the reception process and generates the J1850 reception (J1850RX) interrupt (if it is enable d), signaling that JRX_BUF is av ailable for another byte (Figure 8-15).

CPU

Figure 8-15. J1850 Receive Message Structure

After J_RX is read, the byte residing in JRX_BUF is automatically shifted into J_RX, freei ng JRX_BUF for another reception. This process continues until an end of data (EOD) symbol is encountered.

JRX_BUF

J_RX

J1850 Bus

Message receive interrupt (J1850RX) set

A5236-01

8-15

8XC196LX SUPPLEMENT

If a third byte is received before J_RX is read, a J1850ST core interrupt is generated and the OVR_UNDR (J_STAT.3) bit records a receiver overrun error in the J_STAT register.

8.5.3 IFR Messages

In-frame response (IFR) messaging is identical in setup to standard messaging for both transmission and reception. It uses the same registers to configure, communicate, and control data. The difference is that the requestor initiating the IFR message sequence writes the message specifying a response from either one or more nodes in the system. Framing a message in this manner bypasses needless CPU overhead that can result from lengthy EOF symbols, and it gives you a faster response to the information you are accessing from remote sites in your system. (Refer to “In-

frame Response Messaging” on page 8-12 for a detailed explanation).

8.6 PROGRAMMING THE J1850 CONTROLLER

This section explains how to configure the J1850 controller . Several registers combine to control the configuration: the command register, the configuration register, the delay compensation register, and the status register.

Programming the J1850 controller requires that you first program the configuration and delay registers during initialization. You need to program thes e two registers only once per initialization sequence.

After initialization, you must first program the command register, followed by either the receive or transmit register, and then the status register.

8.6.1 Programming the J1850 Command (J_CMD) Register

The J1850 command register (Figure 8-1 6) d etermines the messaging type, specifies the number of bytes to be transmitted in the next message frame, and u pdates the status of the message transmission in pr ogress.

8-16

J1850 COMMUNICATIONS CONTROLLER

J_CMD

The J1850 command (J_CMD) register determines the messaging type, specifies the number of bytes to be transmitted in the next message frame, and updates the status of the message transmission in progress. This byte register can be directly addressed through register prior to transmitting every message.

7 0

AUTO IFR IGNORE ABORT MSG3 MSG2 MSG1 MSG0

Bit

Number

7 A UTO Automatic Transmit Retry

6 IFR In-frame Response Indicator

Bit

Mnemonic

This bit, when arbitration is lost on the first byte of your message, prompts the transmitter to automatically retry until the byte is successfully transmitted. Automatic retry applies only to the first byte.

0 = normal operation 1 = enable automatic retry

This bit signals that a normalization bit (NB) is to be sent after an end-ofdata symbol is detected on the bus and that the subsequent byte written to the J1850 transmitter (J_TX) register is an in-frame response (IFR).

0 = standard messaging 1 = next byte written to J_TX is an IFR

windowing

Function

Address:

Reset State:

. You must write to this

1F51H

00H

5 IGNORE Ignore Incoming Message

This bit instructs the bus to ignore the incoming message until an EOF symbol is detected. The bit is cleared after an EOF symbol is detected.

0 = normal operation 1 = ignore incoming message

4 A BO RT Abort Transmission

This bit aborts any transmission in progress and flushes the transmit buffer (JTX_BUF). To prevent another node from mistakenly assuming that the

last byte was a CRC byte, two extra ‘1’s are appended. 0 = normal operation

1 = abort transmission in progress

3:0 MSG3:0 Message

These four bits specify the number of bytes to be transmitted in the next message frame. This number includes the header, but not the CRC byte. In normal messaging, the maximum number of bytes you can transmit in a message frame is eleven.

MSG3:0 Operation Purpose

FH Terminati on byte Terminate block transmission EH Block transmission Transmit unspecified number of bytes DH Reserved — CH Reserved — B:0H Normal messaging Transmit specified number of bytes

Figure 8-16. J1850 Command (J_CMD) Register

8-17

8XC196LX SUPPLEMENT

8.6.2 Programming the J1850 Configuration (J_CFG) Register

The J1850 configuration register (Figure 8-17) selects the prop er oscillator prescal er, initiates a transmission break for debugging, invokes clock quadrupling operation, and selects the normalization bit format.

J_CFG

The J1850 configuration (J_CFG) register selects the proper oscilator prescaler, init iates transmission break for debug, invokes clock quadrupling operation, and selects the normalizartion bit format. This byte register can be directly addressed through first write to this register.

7 0

NBF IFR3 4XM TXBRK RXPOL — PRE1 PRE0

Bit

Number

7 NBF Normalization Bit Format

6 IFR3 Type 3 IFR Messaging

Bit

Mnemonic

This bit specifies which normalization bit (NB) format is to be used.

IFR with CRC Byte IFR without CRC Byte

0 = active long NB 0 = active short NB 1 = active short NB 1 = active long NB

This bit selects type 3 IFR messaging, which supports the in-frame transfer of an unspecified number of data bytes.

0 = normal operation 1 = type 3 IFR messaging

windowing

. All J1850 bus activity is ignored until you

Function

Address:

Reset State:

1F54H

00H

5 4XM Oscillator Quadruple (4x) Mode

This bit allows the J1850 peripheral to operate at four times the normal bit transfer rate (41.6 Kb/s versus 10.4 Kb/s).

0 = normal operation 1 = 4x mode operation

4 TXBRK Transmission Break

This bit will terminate any transmission in progress by writing a break (BRK) symbol to the bus.

0 = normal operation 1 = transmit BRK symbol onto bus

3 RXPOL Receive Polarity

This bit changes the polarity of the receive symbol. 0 = normal operation – Rx input inverted

1 = receive polarity enabled – Rx input non-inverted

Figure 8-17. J1850 Configuration (J_CFG) Register

8-18

J1850 COMMUNICATIONS CONTROLLER

J_CFG

7 0

NBF IFR3 4XM TXBRK RXPOL — PRE1 PRE0

Bit

Number

2 — Reserved; for compatibility with future devices, write zero to this bit. 1:0 PRE1:0 J1850 Oscillator Prescaler

Bit

Mnemonic

These bits ensure proper operation of the J1850 peripheral at the supported input frequencies (F

PRE1 PRE0 F

00 8 MHz 0 1 12 MHz 1 0 16 MHz 1 1 20 MHz

windowing

XTAL1

. All J1850 bus activity is ignored until you

Function

Address:

Reset State:

1F54H

00H

Figure 8-17. J1850 Configuration (J_CFG) Register (Continued)

8.6.3 Programming the J1850 Delay Compensation (J_DLY) Register

The J1850 delay compensation register (Figur e 8-1 8) allows y ou to pro gram the n ecessary delay time through the external transceiver to compensate for the inherent propagation delays and to accurately resolve bus contention during arbitration.

8-19

8XC196LX SUPPLEMENT

J_DLY

The J1850 delay (J_DLY) register allows you compensate for the inherent propagation delays and to accurately resolve bus contention during arbitration. This byte register can be directly addressed through

7 0

Number

7:5 — Reserved; for compatibility with future devices, write zeros to these bits. 4:0 DLY4:0 Delay Time

windowing

— — — DLY4 DLY3 DLY2 DLY1 DLY0

Bit

Mnemonic

Function

These five bits specify the desired propagation delay between the J1850 controller circuitry and the off-chip transceiver device, in units of microseconds (µs).

Address:

Reset State:

1F58H

00H

Figure 8-18. J1850 Delay (J_DLY) Register

8-20

J1850 COMMUNICATIONS CONTROLLER

8.6.4 Programming the J1850 Status (J_STAT) Register

The J1850 status register (Figure 8-19) provides the current status of the message and the four interrupt sources associated with the J1850 protocol.

J_STAT

The J1850 status (J_STAT) register provides the current status of the message transfer, the receive and transmit buffers, and the four interrupt sources associated with the J1850 protocol. This byte register can be directly addressed through transmitting each message. Reading this register clears all bits except BUS_STAT.

7 0

IFR_RCV BUS_CONT BUS_STAT BRK_RCV OVR_UNDR MSG_TX MSG_RX J1850BE

Bit

Number

7 IFR_RCV In-frame Response Received

6 BUS_CONT J1850 Bus Contention

Bit

Mnemonic

This bit indicates whether the IFR byte has been received and is ready to be read from the J1850 receiver (J_RX) register.

0 = no action 1 = IFR byte received

This bit indicates whether bus contention has been detected and arbitration has been lost.

0 = no action 1 = bus contention

windowing

. You must write to this register before

Function

Address:

Reset State:

1F53H

00H

5 BUS_STAT J1850 Bus Status

This bit indicates whether a transmission or reception is in progress on the J1850 bus.

0 = J1850 bus idle 1 = J1850 bus busy

4 BRK_RCV Break Received

This bit indicates whether a BRK symbol has been detected on the J1850 bus.

0 = no action 1 = BRK symbol detected

3 OVR_UNDR Receive Overrun/Transmit Underflow Interrupt

This bit indicates whether a receive buffer overrun (OVR) or transmit buffer underflow (UNDR) has occurred. An overrun occurs when a symbol is received while both J_RX and JRX_BUF contain unread bytes. An underflow occurs when a transmission is attempted while both J_TX and JTX_BUF are empty.

0 = normal operation 1 = OVR or UNDR detected

Figure 8-19. J1850 Status (J_STAT) Register

8-21

8XC196LX SUPPLEMENT

J_STAT

7 0

IFR_RCV BUS_CONT BUS_STAT BRK_RCV OVR_UNDR MSG_TX MSG_RX J1850BE

Bit

Number

2 MSG_TX Message Transmit Interrupt

1 MSG_RX Message Receive Interrupt

0 J1850BE J1850 Bus Error Interrupt

Bit

Mnemonic

This bit signals the successful transmission of a message upon detecting the EOD symbol.

0 = no action 1 = message transmitted

This bit signals the successful reception of a message upon detecting the EOD symbol.

0 = no action 1 = message received

This bit is set if one or more of the following conditions occur:

• t he calculated CRC for a received message does not equal C4H

• an incomplete byte is received on the bus

• an invalid bus symbol is detected on the bus

• a tr ansm ission occurs and the feedback through the receiver is not detected within 60 µs

windowing

. You must write to this register before

Function

Address:

Reset State:

1F53H

00H

Figure 8-19. J1850 Status (J_STAT) Register (Continued)

8-22

Minimum Hardware Considerations

CHAPTER 9

MINIMUM HARDWARE CONSIDERATIONS

This chapter discusses the major hardware consideration differences between the 8XC196Lx and the 8XC196Kx. The 8XC196Lx has implemented a reset source SFR that reveals the source of the most recent reset request.

9.1 IDENTIFYING THE RESET SOURCE

The reset source (RSTSRC) register indicates the source of th e last reset that the m icrocon troller encountered (Figure 9-1). If more than one reset occur s at the same time, all of the corresponding RSTSRC bits are set. Reading this SFR clears all the register bits.

RSTSRC

The reset source (RSTSRC) register indicates the source(s) of the last reset that the microcontroller encountered.

7 0

— — — — CFDRST WDTRST SFWRST EXTRST

Bit

Number

7:4 — Reserved; for compatibility with future devices, write zeros to these bits. 3 CFDRST Clock Failure Detection Reset

2 WDTRST Watchdog Timer Reset

1 SFWRST Software Reset

0 EXTRST Ex ternal Reset

NOTE:

1. The State of the RSTSRC register is inderterminate on a V states will have the corresponding reset event bit set in the register.

Bit

Mnemonic

Function

When set, this bit indicates that a failed clock caused the last reset.

When set, this bit indicates that the watchdog timer caused the last reset.

When set, this bit indicates that either the RST instruction or the IDLPD instruction used with an illegal key caused the last reset.

When set, this bit indicates that the RESET# pin being asserted caused the last reset.

power up condition. All other reset

Address:

Reset State:

1F92H

(1)

XXH

Figure 9-1. Reset Source (RSTSRC) Register

9-1

8XC196LX SUPPLEMENT

9.2 DESIGN CONSIDERATIONS FOR 8XC196LA, LB, AND LD

Follow these recommendations to help maintain hardware and software comp atibility between the 8XC196Lx, 8XC196Kx, and future microcontrollers.

• Bus width. Since the 8XC196Lx has neither a WRH# nor a BUSWIDTH pin, the

microcontroller cannot dynamically switch between 8- and 16-bit bus widths. Program the CCBs to select 8-bit bus mode.

• Wait states. Since the 8XC196Lx has no READY pin, the microcontro ller canno t rely on a

READY signal to control wait states. Program the CCBs to limit the number of wait states (0, 1, 2, or 3).

• EPA6–EPA7. These functions exist in the 8XC196Lx, but the associated pins are omitted.

You can use these functions as software timers, to start A/D conversions (on 87C196LA and LB only), or to reset the timers.

• Slave port. Since the 8XC196Lx has no P5.1/SLPCS and P5.4/SLPINT pins, you cannot

use the slave port.

• ONCE mode. On the 8XC196Lx, the ONCE mode entry function is multiplexed with P2.6

(and TXJ1850 on the 87C196LB) rather than with P5.4 as it is on the 8XC196Kx (P5.4/SLPINT/ONCE).

• NMI. Since the 8XC196Lx has no NMI pin, the nonmaskable interrupt is not supported.

Initialize the NMI vector (at location 203EH) to point to a RET instruction. This method provides glitch protection only .

• I/O ports. The following port pins do not exist in the 8XC196Lx: P0.0–P0.1, P1.4–P1.7,

P2.3 and P2.5, P5.1 and P5.4–P5.7, P6.2 and P6.3. Software can still read and write the associated Px_REG, Px_MODE, and Px_DIR registers. Configure the registers for the omitted pins as follows:

— Clear the corresponding Px_DIR bits. (Configures pins as complementary outputs.) — Clear the corresponding Px_MODE bits. (Selects I/O port function.) — Write either “0” or “1” to the corresponding Px_REG bits. (Effectively ties signals low

or high.)

Do not use the bits associated with the omitted port pins for conditional branch instructions. Treat these bits as reserved.

• Auto programming. During auto programming, the 8XC196Lx supports only a 16-bit,

zero-wait-state bus configuration.

9-2

Special Operating Modes

CHAPTER 10

SPECIAL OPERATING MODES

The 8XC196Lx’s idle and powerdown modes are t he same as t hose of th e 8XC196 Kx. However, the clock circuitry has changed, and the on-circuit emulation (ONCE) special-purpose mode operation has changed slightly because of the new reset state pin levels that have been implemen ted.

10.1 INTERNAL TIMING

The 87C196LA and LB clock circuitry (Figure 10-1) implements a phase-locked loop and clock multiplier circuitry, which can substantially increase the CPU clock rate while using a lower-frequency input clock.

10-1

8XC196LX SUPPLEMENT

XTAL1

XTAL2

XTAL1

Disable Oscillator (Powerdown)

XTAL1

Disable

PLL

(Powerdown)

PLLEN

XTAL1

Divide by two

Circuit

Clock

Generators

Phase

Comparator

Phase-locked

Oscillator

Phase-locked Loop

Clock Multiplier

Disable Clock Input (Powerdown)

f/2

Clock

Failure

Detection

f/2

Filter

To reset logic

Disable Clocks (Idle, Powerdown)

CPU Clocks (PH1, PH2)

Peripheral Clocks (PH1, PH2)

Programmable

Divider

(CLK1:0)

OSC

CLKOUT

Disable Clocks (Powerdown)

A5290-01

Figure 10-1. Clock Circuitry (87C196LA, LB Only)

10.2 ENTERING AND EXITING ONCE MODE

ONCE mode isolates the device from other components in the system to allow printed-circuitboard testing or debugging with a clip-o n emulator. During ONCE mode, all pins except XTAL1, XTAL2, V

, and VCC are weakly pulled either high or low. During ONCE mode, RESET# must

be held high or the device will exit ONCE mode and enter the reset state. On the 87C196LA and LB, the reset state level of all 41 general-purpose I/O pins has changed

from a weak logic “1” (wk1) to a weak logic “0” (wk0). ONCE shares a package with port pin

2.6. Asserting and holding the ONCE signal high during the rising edge of RESET# causes the device to enter ONCE mode. To prevent accidental entry into ONCE mode, configure this pin as

10-2

SPECIAL OPERATING MODES

an output. If you cho os e t o configure this pin as an i n put, always hold it low durin g r e set an d ensure that your system meets the V

specification to prevent inadvertent entry into ONCE mode.

10-3

Programming the Nonvolatile Memory

Intel 8XC196Jx, 8XC196Kx, 8XC196Lx, XC196Kx Supplement To User’s Manual

Specifications and Main Features

Frequently Asked Questions

User Manual