J1850 Communications Controller, PLL Clkout | Intel 87C196CA

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) 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. Its lower cost per node makes it suitable for diag- nostics 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.

8.1J1850 FUNCTIONAL OVERVIEW

The integrated J1850 communications controller transfers messages between network nodes ac- cording 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 protocol with the J1850 controller integrated on the 87C196LB 16-bit microcontroller and a standalone J1850 bus transceiver device. The example uses the Har- ris HIP7020 as the remote transceiver device.

	TXJ1850	TX	J1850
		HIP7020	Bus
	RXJ1850	RX
	87C196LB
	Microcontroller
Clock	PLL/
Clock	CLKOUT
	CLKOUT
			A5168-01

Figure 8-1. Integrated J1850 Communications Protocol Solution

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.

8-1

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Intel 87C196CA, 8XC196Jx, 8XC196Lx, 8XC196Kx J1850 Communications Controller, J1850 Functional Overview, PLL Clkout

Contents

August Page Contents 8XC196LX Supplement Chapter Synchronous Serial I/O Port Internal Timing Entering and Exiting Once ModeFunctional Groupings of Signals Default Conditions Programming the J1850 Controller Figures 11-3 Tables Guide to This Manual Page Chapter Guide to this Manual Manual Contents Related Documents Related Documents Architectural Overview Page Features of the 8XC196Lx and 8XC196Kx Product Famiies Microcontroller FeaturesChapter Architectural Overview Internal Timing Block Diagram Clock Circuitry 87C196LA, LB Only 16 MHz State Times at Various FrequenciesMHz 12 MHz Pllen External TimingMultiplier State Time Uprom Programming Values and Locations Internal PeripheralsCLK1 CLK0 4 J1850 Communications Controller 1 I/O PortsSynchronous Serial I/O Port Event Processor ArrayPage Address Space Page Address Partitions Chapter Address SpaceAddress Map 1BFF Register File CA,JT,KT AddressJR, KR XC196Lx Peripheral SFRs Peripheral SPECIAL-FUNCTION RegistersUSFR1 LA, LB Jdly SSIO1CLKSSIO0CLK Rstsrc Windows Windowing Upper Register File CA, JT, JV, KT BaseUpper Register File CA, JT, JV, KT, LA, LB 0140H 4BH25H 0120H 49H 0100H 48H 24H 12H Standard and PTS Interrupts Page Interrupt SOURCES, VECTORS, and Priorities Chapter Standard and PTS Interrupts Interrupt Source Mnemonic Priority Name Interrupt Controller PTS ServiceInterrupt Registers Interrupt Sources, Vectors, and Priorities Bit Mnemonic Interrupt Description Interrupt Mask RegistersIntmask Bit Function Number NMI Extint SSIO1 SSIO0 Interrupt Pending RegistersINTMASK1 LA, LD Intpend Interrupt Pending Intpend Register INTPEND1 Peripheral Transaction Server RegistersNMI Bit PtsselInterrupt PTS Vector Bits PtssrvInterrupt Standard Vector Ports Page EPA, Ssio Chapter PortsI/O Ports Overview Microcontroller Ports 8XC196LX Supplement Ports 1, 2, 5, and 6 Internal Structure 87C196LA, LB Only Configuring Ports 1, 2, 5, and 6 Bidirectional Ports Special Bidirectional Port Considerations For complementary output configurations Internal Structure for Ports 3 and 4 ADDRESS/DATA BUS 8XC196L X Supplement Synchronous Serial Port Page For receptions Chapter Synchronous Serial I/O PortSsio 0 Clock Register Bit Function CHS Ssio 1 Clock Register1FB7H CHS DUP Conint Conpnd Phas Pols SSIO1CLK Page Event Processor Array Page Device Capture/Compare Compare-only Chapter Event Processor ArrayEPA Functional Overview EPA Channels EPA Block Diagram 87C196LA, LB Only EPA Block Diagram 83C196LD Only Epamask EPA Mask RegistersEPAMASK1 Epapend EPA Pending RegistersEPAPEND1 Value Interrupt EPA Interrupt Priority Vector RegisterEpaipv J1850 Communications Controller Page J1850 Functional Overview J1850 Communications ControllerPLL Clkout J1850 Communications Controller Block Diagram Control and Status Registers J1850 Controller Signals and RegistersJ1850 Controller Signals Signal Control State Machine J1850 Controller OperationCyclic Redundancy Check Generator Bit Arbitration Symbol Synchronization and Timing CircuitryBus Contention Error Detection Digital Filter Delay CompensationSymbol Encoding and Decoding Clock Prescaler Bit Arbitration Example Huntzicker Symbol Definition for J1850 Bit Arbitration Example Message Frames Normalization Bit Standard MessagingHeader CRC Byte 64µS 128µS NB for IFR with CRC NB for IFR without CRC Name Symbol Bus Level TXmin TXnom TXmax RXmin RXmax Units Huntzicker Symbol Timing Characteristics IFR Messaging Type 1 Single Byte, Single Responder In-frame Response Messaging Transmitting Messages Transmitting and Receiving Messages CPU JTX Jtxbuf Transmit Byte Receive Byte Receiving MessagesCPU Jrxbuf IFR Messages Programming the J1850 Command Jcmd RegisterProgramming the J1850 Controller MSG30 Operation Purpose JcmdAuto IFR Ignore Abort MSG3 MSG2 MSG1 MSG0 Auto IFR without CRC Byte Programming the J1850 Configuration Jcfg RegisterNBF IFR3 4XM Txbrk Rxpol PRE1 PRE0 NBF PRE1 PRE0 Programming the J1850 Delay Compensation Jdly Register 18. J1850 Delay Jdly Register Jstat Programming the J1850 Status Jstat Register Msgrx Msgtx Minimum Hardware Considerations Page Minimum Hardware Considerations Identifying the Reset Source Design Considerations for 8XC196LA, LB, and LD Special Operating Modes Page Chapter Special Operating Modes Entering and Exiting Once Mode 10-3 Page Programming Nonvolatile Memory Page Signature Word and Programming Voltage Values Programming the Nonvolatile MemorySignature Word and Programming Voltage Values Otprom Address MAP CCB1 Slave Programming Circuit and Address MAPC196LA, LB Otprom Address Map Address Range Description Hex Description Address Comments Serial Port Programming Circuit Serial Port Programming Circuit and Address MAP Do not address Serial Port Programming Mode Address MapDescription Address Range A000-FFFFHPage Signal Descriptions Page Functional Groupings of Signals Appendix a Signal Descriptions Table A-1 C196LA Signals Arranged by Functional Categories Signal Descriptions Table A-2 C196LB Signals Arranged by Functional Categories Figure A-2 C196LB 52-pin Plcc Package Bus Control & Status Table A-3 C196LD Signals Arranged by Functional CategoriesInput Name Pin Input/Output Cont’d Name Pin Default Conditions Port Alternate During RESET# Upon RESET# Power Table A-5 C196LA, LB Default Signal ConditionsSignals Functions Table A-6 C196LD Default Signal Conditions Page Glossary Page ALU GlossaryBIT Byte EPA DOUBLE-WORDESD Integer FET LSW ISRLONG-INTEGER LSB MSW MSB PIC PIH PLL PTS PSWPtscb Ralu QUAD-WORD SFR SARSHORT-INTEGER Uart WDT VPWWord Index Page Clkout Index Index-2