I have a problem at my new prototype build on w65c265. My project use this input for counting and time checking beetwen a pluses form crank sensor on a engine.
This routine work correctly at older project based on 6502 and 8520 CIA (from Amiga 500).
I read a datasheet from WDC , but i still dont know how Timer 7 working.
If i understand correctly - a defined edge on PWM pin generating interrupt - this work ok. A timer7 counters at this moment are latching at T7CL and T7CH.
But when i reading this registers my routine work verry strange.
Maybe i must read T7Cl first, maybe write to eifr first, maybe ........ i dont know
Now is some part of my code:
irpe62 pha
; copy timer7 latched data into memory
lda t7ch
sta bak_todmid
lda t7cl
sta bak_todlo
lda pd4 ; for checking interrupt response
eor #%0010000 ; at every pulse change bit at PD4
sta pd4
; $ffff - TIMER7 value
sec
lda #$ff
sbc bak_todlo
sta bak_todlo
lda #$ff
sbc bak_todmid
sta bak_todmid
; calculate tod-oldtod/2
lda bak_todlo
sec
sbc old_todlo
lda bak_todmid
sbc old_todmid
bcs next_tooth
; obsluga zabka indexowego
lda pd4 ;
and #%11101111 ;
sta pd4 ;
jmp end_tooth ; kasuj poprzedni licznik!
next_tooth
lda pd4
ora #%00010000
sta pd4
lda #$ff ; zliczaj od nowa - czyli $ffff
sta T7CL
sta T7CH
end_tooth
lda bak_todmid
lsr a
sta old_todmid
lda bak_todlo
ror a
sta old_todlo
no_flag
lda #%00001000
sta eifr
pla
rti
Please help me, i spent a 4 days for checking this routine and i dont know why i cant read data from timer correctly ?
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