http://www.sega-16.com/forum/showthread.php?20691
But i discovered something interesting. I wrote a z80 program that plays a sinewave over the pcm channel.
Here is the code:
Code: Select all
stack: equ $1ff0
ld sp, stack
ld a, $0
ld ix, $4000
ld (ix), $2B
ld (ix+1), $FF
ld (ix), $2A
redo:
ld hl, sine
ld a, $FF
loop:
ld b, (hl)
ld (ix+1), b
inc hl
dec a
jp z, redo
jp loop
sine:
incbin "sine.bin"
I don't wait for the ready bit to become set and I accidentally made it so one period is 256 bytes. So basically if I have a 440hz sinewave that would be ~112khz i'd be stuffing into that poor YM.
Now, the curious thing is, that it actually doesn't crash. It's probably missing a shitload of writes, but it doesn't crash. My question is: why?
Because lots of people said that after like 52khz the thing will just crash hard. And this is not happening for me.
Cheers,
Oerg866
EDIT: I then took 1 second of 48KHz music and let the 68k doit this time.
Result is this: http://www.mdscene.net/~pvt/Untitled7.wav
This is ~10 times the speed of the original 48khz sample. So for some reason, even at like 480khz the thing is not crashing. What is going on down here?!