AN1212 Freescale Semiconductor / Motorola, AN1212 Datasheet - Page 25

• Manufacturer Part Number: AN1212
• Description: J1850 Multiplex Bus Communication Using the MC68HC705C8 and the SC371016 J1850 Communications Interface (JCI)
• Manufacturer: Freescale Semiconductor / Motorola

MOTOROLA
NO
NO
NO
TEMPORARY STORAGE
BIT COMBINATION INTO
INTO SPDR, INITIATING
INTO SPDR, INITIATING
LOCATION "data" INTO
"command" AND "data"
LOCATION "command"
LOCATION "command"
LOAD BYTE IN SPDR
LOAD BYTE IN RAM
LOAD BYTE IN RAM
LOAD BYTE IN RAM
LOCATION "status"
STORE CURRENT
SPDR, INITIATING
LOAD "flush byte"
LOCATION "data"
IRQ INTERRUPT
INTO MCU RAM
SPI TRANSFER
SPI TRANSFER
SPI TRANSFER
SPI TRANSFER
SPI TRANSFER
SPI TRANSFER
COMPLETE?
COMPLETE?
COMPLETE?
VALUES IN
MCU RAM
YES
YES
YES
OCURS
IS
IS
IS
Figure 14. IRQ Interrupt Service Routine (Sheet 1 of 2)
J1850 Multiplex Bus Communication Using the MC68HC705C8
and the SC371016 J1850 Communications Interface (JCI)
Freescale Semiconductor, Inc.
For More Information On This Product,
NO
Go to: www.freescale.com
INTO SPDR, INITIATING
LOCATION "command"
LOAD BYTE IN SPDR
LOAD BYTE IN SPDR
LOAD BYTE IN RAM
LOCATION "status"
"data" MATCH I.D.
"data" MATCH I.D.
"data" MATCH I.D.
"data" MATCH I.D.
LOCATION "data"
INTO MCU RAM
INTO MCU RAM
SPI TRANSFER
SPI TRANSFER
COMPLETE?
YES
NO
NO
NO
NO
DOES
DOES
DOES
DOES
#1?
#2?
#3?
#4?
IS
A
YES
YES
YES
YES
MC68HC705C8/JCI Interface Driver Routines
NO
YES
NO
NO
INTO SPDR, INITIATING
MATCHING Rx BUFFER
INTO INDEX REGISTER
LOCATION "data" INTO
LOCATION "command"
LOAD BYTE IN SPDR
LOAD BYTE IN RAM
LOAD BYTE IN RAM
LOAD POINTER TO
LOCATION "status"
SPDR, INITIATING
BIT 7 OF "status"
BIT 6 OF "status"
SPI TRANSFER
SPI TRANSFER
INTO MCU RAM
SPI TRANSFER
SPI TRANSFER
COMPLETE?
COMPLETE?
YES
YES
YES
NO
SET?
SET?
IS
IS
IS
IS
B
AN1212/D
C
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