ST92F124JDV2TC View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
ST92F124JDV2TC
STMicroelectronics
ST92F124JDV2TC Datasheet PDF : 429 Pages
| |||
ST92F124/F150/F250 - KNOWN LIMITATIONS
KNOWN LIMITATIONS (Cont’d)
Workaround 2
after the acknowledge and the critical slot. If a
Workaround 2 (see Figure 7) first tests that
FMP=2 and the CAN cell is receiving, if not the
FIFO can be released immediately. If yes, the pro-
gram goes through a sequence of test instructions
dominant bit is read on the bus, we can release the
FIFO immediately. This workaround has to be
written in assembly language to avoid the compiler
optimizing the test sequence.
on the RX pin that last longer than the time be- The implementation shown here is for the CAN
tween the acknowledge dominant bit and the crit- bus maximum speed (1MBd @ 8MHz CPU clock).
ical time slot. If the Rx pin is in recessive state for
more than 8 CAN bit times, it means we are now
Figure 6. Reception with TCAN=12/fCPU and sampling time is 16/fCPU
CAN Bus signal R R R D R R R D R R R D R R R D R R R D
Sampling of Rx pin
Figure 7. Workaround 2 in Assembler
asm (“
spp #48
/*
Bytes/cycles
*/
/* set CAN0_CTRL page
2/4
*/
/* Use spp #36 for CAN1
ld
r0, R244
/* For FIFO 0
2/4
*/
/* NB: Replace R244 with R245 for FIFO 1
*/
and r0, #3
/*
3/6
*/
cp
r0, #2
/*
3/6
*/
jxnz _release
/* (JRNE instruction)
2/6
*/
/* if FMP is not 2 then FIFO
*/
/* release can be done
*/
pushw RR232
/* push working group
2/8 or 10
*/
srp #31
/* set group F as working group
2/4
*/
btjf r1.5, _release /* REC bit of CMSR register
3/6 or 10 if jmp
*/
btjf r12.3, _release /* sample RX bit for 8 bit time
3/6 or 10 if jmp
*/
btjf r12.3, _release /* ie. 11 btjf instructions
3/6 or 10 if jmp
*/
btjf r12.3, _release /*
3/6 or 10 if jmp
*/
btjf r12.3, _release /*
3/6 or 10 if jmp
*/
btjf r12.3, _release /*
3/6 or 10 if jmp
*/
btjf r12.3, _release /*
3/6 or 10 if jmp
*/
btjf r12.3, _release /*
3/6 or 10 if jmp
*/
btjf r12.3, _release /*
3/6 or 10 if jmp
*/
btjf r12.3, _release /*
3/6 or 10 if jmp
*/
btjf r12.3, _release /*
3/6 or 10 if jmp
*/
btjf r12.3, _release /*
3/6 or 10 if jmp
*/
_release: or R244, #32
/* set RFOM bit of CRFR0 register 3/6
*/
/* NB: Replace R244 with R245 for FIFO 1
*/
popw RR232
/* restore previous working group 2/10
*/
“);
418/429
1
Share Link: 