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Trifox
Account closed
Registered: Mar 2006
Posts: 108 |
question about triggered raster line in raster interrupt
i am using this code
to initialise my interrupt
this should look fairly common:
(pasted from somewhere ... )
; Initialise Music Interrupt
sei ; turn off interrupts
lda #$7f
ldx #$01
sta $dc0d ; Turn off CIA 1 interrupts
sta $dd0d ; Turn off CIA 2 interrupts
stx $d01a ; Turn on raster interrupts
lda $d011
;ldx #%1000
;ldy #$14
and #%01111111
sta $d011 ; Clear high bit of $d012, set text mode
;stx $d016 ; single-colour
;sty $d018 ; screen at $0400, charset at $2000
lda #<int ; low part of address of interrupt handler code
ldx #>int ; high part of address of interrupt handler code
ldy #0 ; line to trigger interrupt
sta $0314 ; store in interrupt vector
stx $0315
sty $d012
lda $dc0d ; ACK CIA 1 interrupts
lda $dd0d ; ACK CIA 2 interrupts
asl $d019 ; ACK VIC interrupts
cli
to init my interrrupt, i encountered that this interrupt is triggered in row 256 :( what must i do to let it trigger on exactly line 0 ? and only there, not on line 0 AND 256 ... know what i mean ?
i am leaving the interrupt with following fragment:
; Initialise Music Interrupt
sei ; turn off interrupts
lda #$7f
ldx #$01
sta $dc0d ; Turn off CIA 1 interrupts
sta $dd0d ; Turn off CIA 2 interrupts
stx $d01a ; Turn on raster interrupts
lda $d011
;ldx #%1000
;ldy #$14
and #%01111111
sta $d011 ; Clear high bit of $d012, set text mode
;stx $d016 ; single-colour
;sty $d018 ; screen at $0400, charset at $2000
lda #<int ; low part of address of interrupt handler code
ldx #>int ; high part of address of interrupt handler code
ldy #0 ; line to trigger interrupt
sta $0314 ; store in interrupt vector
stx $0315
sty $d012
lda $dc0d ; ACK CIA 1 interrupts
lda $dd0d ; ACK CIA 2 interrupts
asl $d019 ; ACK VIC interrupts
cli
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TWW
Registered: Jul 2009
Posts: 545 |
dec $d019? |
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SIDWAVE
Account closed
Registered: Apr 2002
Posts: 2238 |
RTFM...
the correct thing is poke d019,1 |
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Mace
Registered: May 2002
Posts: 1799 |
awww... please close this thread, it's many moons old :( |
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