Scanlines and ppu

Hi,

Trying to find a simple way to track scanlines,

so I can JSR something every scanline!

Is there a way to IRQ easly using the ppu ? Any ideas?

I need to do that without interfering with my music. counting to 241 in a loop seems to slow.


.segment "CODE"


INFLOOP:


;JSR PLAY_MUSIC1
;JSR REST_QUARTERSEC
;JSR REST_QUARTERSEC
;JSR PLAY_MELODY
;JSR REST_QUARTERSEC
;JSR PLAY_MELODY2
;JSR REST_QUARTERSEC
;JSR PLAY_MELODY3
;JSR FOLLOWUP_MELODY
;JSR REST_QUARTERSEC
;JSR PLAY_MUSIC1
;JSR REST_QUARTERSEC


;JSR BIG_BOOM_SOUND
JSR PLAY_MUSIC2
JSR REST_QUARTERSEC
JSR PLAY_MUSIC2
JSR REST_QUARTERSEC
JSR PLAY_MUSIC3
JSR REST_QUARTERSEC
JSR PLAY_MUSIC3
JSR REST_QUARTERSEC

JMP INFLOOP

; Jump back to the start of the loop
; Jump back to the start of the loop
NMI:

;Disable sound IRQ (set the corresponding bit)
LDX #%11000000
STX APU_PAD2


;; Backup A, X, Y registers
PHA ; Push A to the stack
TXA ; Transfer X to A
PHA ; Push X (now in A) to the stack
TYA ; Transfer Y to A
PHA ; Push Y (now in A) to the stack

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
INC frame_counter ; Increment the frame counter
INC sound_frame_counter ; Increment the counter every NMI
INC RANDOM_SEED
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

JSR HEARTS_CHECK


(rest of nmi)

RTI

Statistics: Posted by v.depatie — Sat Dec 21, 2024 9:09 pm — Replies 3 — Views 139

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