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Intel 87C196CB, 8XC196NT user manual Can Serial Communications Controller, Can Functional Overview

Models: 8XC196NT 87C196CB

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CHAPTER 7 CAN SERIAL COMMUNICATIONS CONTROLLER

CHAPTER 7 CAN SERIAL COMMUNICATIONS CONTROLLER

The 87C196CB has a peripheral not found in the 8XC196NT — the CAN (controller area net- work) peripheral. The CAN serial communications controller manages communications between multiple network nodes. This integrated peripheral is similar to Intel’s standalone 82527 CAN serial communications controller. It supports both the standard and the extended message frames specified by CAN 2.0 protocol parts A and B developed by Robert Bosch, GmbH. This chapter describes the integrated CAN controller and explains how to configure it. Consult Appendix A, “Signal Descriptions,” for detailed descriptions of the signals discussed in this chapter.

7.1CAN FUNCTIONAL OVERVIEW

The integrated CAN controller transfers messages between network nodes according to the CAN protocol. The CAN protocol uses a multiple-master, contention-based bus configuration, which is also called CSMA/CR (carrier sense, multiple access, with collision resolution). Each CAN controller’s input and output pins are connected to a two-line CAN bus through which all com- munication takes place (Figure 7-1).

ABS
	RXCAN		CAN_L				Dashboard
196Cx		Bus				Rx0	Dashboard
196Cx	TXCAN	Bus	CAN_H	CAN_L		Rx0		Bus
device	TXCAN	Driver	CAN_H		Bus		82527	CPU
				CAN_H	Bus	Tx0
					Driver
					Driver
Engine
	RXCAN		CAN_L			Security System
196Cx						Security System
196Cx		Bus		CAN_L		Rx0		Bus
		Bus
device	TXCAN	Driver CAN_H
device	TXCAN	Driver CAN_H			Bus
				CAN_H	Bus	Tx0	82527	CPU
					Driver		82527	CPU
					Driver
Transmission				Bus
196Cx	RXCAN		CAN_L	Bus
196Cx		Bus		CAN
device		Bus
device	TXCAN	Driver CAN_H
	TXCAN	Driver CAN_H
								A2588-02

Figure 7-1. A System Using CAN Controllers

7-1

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Intel 87C196CB, 8XC196NT user manual Can Serial Communications Controller, Can Functional Overview

Contents

87C196CB Supplement to 8XC196NT User’s Manual Order Number 87C196CB Supplement to 8XC196NT User’s ManualAugust Copyright Intel Corporation, 1998 GUIDE TO THIS MANUAL CONTENTSCHAPTER CHAPTERCHAPTER SIGNAL DESCRIPTIONS87C196CB SUPPLEMENT SPECIAL OPERATING MODESInternal Clock Phases FIGURESCONTENTS Effect of Clock Mode on CLKOUT FrequencyPage FIGURES8XC196CB SUPPLEMENT 87C196CB 100-pin QFP PackagePage TABLESCONTENTS Page Guide to This Manual Page 1.1 MANUAL CONTENTS CHAPTER GUIDE TO THIS MANUALChapter 9 - Interfacing with External Memory 1.2 RELATED DOCUMENTSAppendix A - Signal Descriptions Architectural Overview Page 2.1 DEVICE FEATURES CHAPTER ARCHITECTURAL OVERVIEW2.2 BLOCK DIAGRAM 2.3 INTERNAL TIMINGPage 16 MHz 8 MHz12 MHz 20 MHzFrequency Figure 2-4. Effect of Clock Mode on CLKOUT FrequencyARCHITECTURAL OVERVIEW Input Frequency toPage Memory Partitions Page CHAPTER MEMORY PARTITIONS 3.1 MEMORY MAP, SPECIAL-FUNCTION REGISTERS, AND WINDOWING87C196CB SUPPLEMENT Table 3-2. 87C196CB Memory Map AddressPorts 0, 1, 2, and 6 SFRs Timer 1, Timer 2, and EPA SFRsMEMORY PARTITIONS Table 3-3. 87C196CB Peripheral SFRs SIO and SSIO SFRs1ECCH 87C196CB SUPPLEMENT Table 3-4. CAN Peripheral SFRs1EDCH MEMORY PARTITIONS Table 3-4. CAN Peripheral SFRs Continued Message64-byte Window 87C196CB SUPPLEMENT Table 3-5. Selecting a Window of Peripheral SFRs32-byte Window 128-byte WindowRegister RAM MEMORY PARTITIONSTable 3-6. Selecting a Window of the Upper Register File Locations87C196CB SUPPLEMENT 0DE0-0DFFH MEMORY PARTITIONSTable 3-7. Selecting a Window of Upper Register RAM 87C196CB SUPPLEMENT Table 3-8. Windows Upper Register File MEMORY PARTITIONSTable 3-8. Windows Continued Table 3-9. WSR Settings and Direct Addresses for Windowable SFRs 87C196CB SUPPLEMENTMEMORY PARTITIONS 87C196CB SUPPLEMENT MEMORY PARTITIONS 87C196CB SUPPLEMENT MEMORY PARTITIONS 87C196CB SUPPLEMENT 64-byte Windows MEMORY PARTITIONS32-byte Windows 128-byte Windows32-byte Windows Standard and PTS Interrupts Page CHAPTER STANDARD AND PTS INTERRUPTS 4.1 INTERRUPT SOURCES, VECTORS, AND PRIORITIESFigure 4-2. interrupt Pending 1 INTPEND1 Register 87C196CB SUPPLEMENTFigure 4-1. Interrupt Mask 1 INTMASK1 Register Standard VectorI/O Ports Page CHAPTER I/O PORTS 5.1 PORT 0 AND EPORTFigure 5-2. Extended Port I/O Direction EPDIR Register Figure 5-3. Extended Port Mode EPMODE Register87C196CB SUPPLEMENT EPDIRFigure 5-5. Extended Port Data Output EPREG Register I/O PORTSFigure 5-4. Extended Port Input EPPIN Register EPPINPage Analog-to-digital A/D Converter Page CHAPTER 6 ANALOG-TO-DIGITAL A/D CONVERTER 6.1 ADDITIONAL A/D INPUT CHANNELS87C196CB SUPPLEMENT Figure 6-1. A/D Command ADCOMMAND RegisterADCOMMAND FunctionADRESULT Read ANALOG-TO-DIGITAL A/D CONVERTERFigure 6-2. A/D Result ADRESULT Register - Read Format FunctionPage CAN Serial Communications Controller Page CHAPTER 7 CAN SERIAL COMMUNICATIONS CONTROLLER 7.1 CAN FUNCTIONAL OVERVIEWPage CAN SERIAL COMMUNICATIONS CONTROLLER 7.2 CAN CONTROLLER SIGNALS AND REGISTERSTable 7-1. CAN Controller Signals Table 7-2. Control and Status Registers7.3 CAN CONTROLLER OPERATION 87C196CB SUPPLEMENT Table 7-2. Control and Status Registers Continued7.3.1 Address Map 7.3.2 Message Objects7.3.2.1 Receive and Transmit Priorities Contents87C196CB SUPPLEMENT Table 7-4. Message Object Structure 7.3.2.2 Message Acceptance Filtering7.3.3 Message Frames 87C196CB SUPPLEMENT Table 7-6. Standard Message Frame Table 7-7. Extended Message Frame7.3.4 Error Detection and Management Logic Definition 7.3.5 Bit TimingSymbol Table 7-9. CAN Controller Bit Time Segments CAN SERIAL COMMUNICATIONS CONTROLLERFigure 7-5. A Bit Time as Implemented in the CAN Controller t SYNC87C196CB SUPPLEMENT 7.3.5.1 Bit Timing Equations whereTable 7-10 defines the bit timing relationships of the CAN controller Table 7-10. Bit Timing Relationships7.4 CONFIGURING THE CAN CONTROLLER 7.4.1 Programming the CAN Control CANCON RegisterFigure 7-6. CAN Control CANCON Register Continued This bit globally enables and disables interrupts error, status-change, and87C196CB SUPPLEMENT 7.4.2 Programming the Bit Timing 0 CANBTIME0 Register UnchangedFigure 7-8. CAN Bit Timing 1 CANBTIME1 Register 7.4.3 Programming the Bit Timing 1 CANBTIME1 Register87C196CB SUPPLEMENT TSEG2Requirement 7.4.4 Programming a Message Acceptance FilterBit Time CommentsCANSGMSK 87C196CB SUPPLEMENTFigure 7-9. CAN Standard Global Mask CANSGMSK Register 87C196CBCANEGMSK CAN SERIAL COMMUNICATIONS CONTROLLERFigure 7-10. CAN Extended Global Mask CANEGMSK Register 87C196CBFigure 7-11. CAN Message 15 Mask CANMSK15 Register 7.5 CONFIGURING MESSAGE OBJECTS87C196CB SUPPLEMENT 7.5.1 Specifying a Message Object’s Configuration Figure 7-13. CAN Message Object x Identifier CANMSGxID0-3 Register 7.5.2 Programming the Message Object Identifier87C196CB SUPPLEMENT Access Type 7.5.3 Programming the Message Object Control Registers7.5.4 Programming the Message Object Data Program the CAN message object x control 0 CANMSGxCON0 register to indicate whether the message object is ready to transmit and to control whether a successful transmission or reception generates an interrupt. The least-significant bit-pair indicates whether an interrupt is pending 87C196CB SUPPLEMENTFigure 7-14. CAN Message Object x Control 0 CANMSGxCON0 Register CAN SERIAL COMMUNICATIONS CONTROLLER 87C196CB SUPPLEMENT Figure 7-15. CAN Message Object x Control 1 CANMSGxCON1 RegisterCAN SERIAL COMMUNICATIONS CONTROLLER Function 87C196CB SUPPLEMENTFigure 7-16. CAN Message Object Data CANMSGxDATA0-7 Registers 7.6 ENABLING THE CAN INTERRUPTS CANCON Continued 87C196CB SUPPLEMENTFigure 7-17. CAN Control CANCON Register Continued 87C196CBWhen the SIE bit in the CAN control register is set, the CAN controller generates a successful reception RXOK interrupt request each time it receives a valid message, even if no message ob- ject accepts it. If you set both the SIE bit Figure 7-17 and an individual message object’s RXIE bit Figure 7-18, the CAN controller generates two interrupt requests each time a message object receives a message. The status change interrupt is useful during development to detect bus errors caused by noise or other hardware problems. However, you should disable this interrupt during normal operation in most applications. If the status change interrupt is enabled, each status change generates an interrupt request, placing an unnecessary burden on the CPU. To prevent re- dundant interrupt requests, enable the error interrupt sources with the EIE bit and enable the re- ceive and transmit interrupts in the individual message objects 7.7 DETERMINING THE CAN CONTROLLER’S INTERRUPT STATUS CAN SERIAL COMMUNICATIONS CONTROLLER Figure 7-20. CAN Status CANSTAT Register87C196CB SUPPLEMENT Figure 7-21. CAN Message Object x Control 0 CANMSGxCON0 Register7.8 FLOW DIAGRAMS Register MnemonicFigure 7-22. Receiving a Message for Message Objects 1-14 - CPU Flow Process message contents87C196CB SUPPLEMENT A2594-01Restart Process CAN SERIAL COMMUNICATIONS CONTROLLERFigure 7-23. Receiving a Message for Message Object 15 - CPU Flow Received frame with 87C196CB SUPPLEMENTFigure 7-24. Receiving a Message - CAN Controller Flow same identifer as thisCAN SERIAL COMMUNICATIONS CONTROLLER Power UpUpdate Figure 7-25. Transmitting a Message - CPU FlowReceived remote frame 87C196CB SUPPLEMENTFigure 7-26. Transmitting a Message - CAN Controller Flow with same identifer as7.9.2 Software Initialization 7.9.1 Hardware Reset7.9 DESIGN CONSIDERATIONS 7.9.3 Bus-off StateThe CAN controller synchronizes itself to the CAN bus by waiting for 128 bus idle states 128 occurrences of 11 consecutive recessive bits before participating in bus activities. During this sequence, the CAN controller writes a bit 0 error code to the LEC20 bits of the status register each time it receives a recessive bit. Software can check the status register to determine whether the CAN bus is stuck in a dominant state. Once the CAN controller is resynchronized with the CAN bus, it clears the BUSOFF bit and starts transferring messages again Special Operating Modes Page Figure 8-1. Clock Circuitry CHAPTER SPECIAL OPERATING MODES8.1 CLOCK CIRCUITRY Page Interfacing with External Memory Page 9.2 BUS TIMING MODES 9.1 ADDRESS PINSCHAPTER 9 INTERFACING WITH EXTERNAL MEMORY T RLDV = 1t 87C196CB SUPPLEMENTFigure 9-1. Modes 0 and 3 Timings T AVDV = 3t= always enabled Figure 9-2. Chip Configuration 1 CCR1 Registerno direct access † INTERFACING WITH EXTERNAL MEMORYCCR1 Continued Figure 9-2. Chip Configuration 1 CCR1 Register Continued87C196CB SUPPLEMENT FunctionProgramming the Nonvolatile Memory Page 10.1 SIGNATURE WORD AND PROGRAMMING VOLTAGES 10.2 MEMORY MAP FOR SLAVE PROGRAMMING MODECHAPTER 10 PROGRAMMING THE NONVOLATILE MEMORY Table 10-3. Auto Programming Memory Map 10.3 MEMORY MAP AND CIRCUIT FOR AUTO PROGRAMMING87C196CB SUPPLEMENT Table 10-2. Slave Programming Mode Memory Map Figure 10-1. Auto Programming Circuit 10.4 MEMORY MAP FOR SERIAL PORT PROGRAMMINGPROGRAMMING THE NONVOLATILE MEMORY 74HC14Serial Port Programming Mode 10.4.1 Selecting Bank 0 FF2000-FF7FFFH10.4.2 Selecting Bank 1 FF8000-FFFFFFH Signal Descriptions Page APPENDIX A SIGNAL DESCRIPTIONS A.1 FUNCTIONAL GROUPINGS OF SIGNALSxx87C196CB 87C196CB SupplementFigure A-1. 87C196CB 84-pin PLCC Package View of component asFigure A-2. 87C196CB 100-pin QFP Package A.2 SIGNAL DESCRIPTIONSSIGNAL DESCRIPTIONS xx87C196CBTable A-2. Description of Columns of Table A-3 Table A-3. Signal Descriptions87C196CB Supplement read or write. AINC# is sampled after each location is programmed or dumped SIGNAL DESCRIPTIONSTable A-3. Signal Descriptions Continued Table A-3. Signal Descriptions Continued 87C196CB SupplementSIGNAL DESCRIPTIONS Table A-3. Signal Descriptions ContinuedTable A-3. Signal Descriptions Continued 87C196CB SupplementSIGNAL DESCRIPTIONS Table A-3. Signal Descriptions ContinuedA-10 Table A-3. Signal Descriptions Continued87C196CB Supplement A-11 SIGNAL DESCRIPTIONSTable A-3. Signal Descriptions Continued A-12 Table A-3. Signal Descriptions Continued87C196CB Supplement A-13 SIGNAL DESCRIPTIONSTable A-3. Signal Descriptions Continued Table A-4. Definition of Status Symbols A.3 DEFAULT CONDITIONSTable A-3. Signal Descriptions Continued 87C196CB SupplementA-15 SIGNAL DESCRIPTIONSTable A-5. 87C196CB Pin Status Continued Page Glossary Page GLOSSARY channel-to-channel matching error transfer function of an A/D convertertwo adjacent code transitions on the A/D converter characteristicconversion result. Differential nonlinearity is a earity errorsSee off-isolation code widthare to be serviced by interrupt service routines that The characteristic of an ideal A/D converter. An ideallinearity errors. Quantizing error is the only error starting address of an interrupt service routinelinearity errors See interrupt service routineSee differential nonlinearity and nonlinearity OTPROM. Consult the Automotive Products or terminal-based characteristic from the correserviced by interrupt service routines that you Embedded Microcontrollers databook to determineprioritized interrupt directly to the interrupt service routine whenSee PTS control block quantizing error transitions from different actual characteristics takenideal A/D converter repeatability errorsample delay Successive approximation register. A component ofthe A/D converter characteristic of the A/D converter service routinescaled to remove zero-offset error and full-scale interrupt controller for processing by an interruptisolation, and VCC rejection errors process quantizing error, zero-offset error, full-scaleerror, differential nonlinearity, and nonlinearity characteristicPage Index Page INDEX 87C196CB SUPPLEMENT Index-2