5 replies to this topic

[Rybags]

Well, not really music, and POKEY's only doing part of the work here.

Real machine required, won't work in an emulator.

Start the machine with BASIC installed.

POKE 53775,2

Now, hold down groups of 3 keys, especially in horizontal rows with each hand.

Try combinations involving SHIFT, CONTROL and also cursor keys and the DELETE key.

[Bryan]

Ah, by turning off key debouncing you cause Pokey to generate rapid-fire interrupts when a key is pressed (Pokey does no "same as last key" checks), so you hear the key click going nuts. I guess multiple keys need to be pressed to fool the OS, though.

-Bry

[analmux]

this is really freaky.....and a feature i've never seen before

also try:

poke 559,0
poke 54286,0

to turn off antic DMA and NMI (vblank interrupts)

then the sound gets cleaner


also freaky what's appearing on the screen...(cursors moving in weird directions, inverse turning on and off all the time etc.)

[Allas]

analmux, on Wed Jun 21, 2006 12:38 PM, said:

this is really freaky.....and a feature i've never seen before

also try:

poke 559,0
poke 54286,0

to turn off antic DMA and NMI (vblank interrupts)

then the sound gets cleaner


also freaky what's appearing on the screen...(cursors moving in weird directions, inverse turning on and off all the time etc.)

The screen go blank, nothing more happens....

[Rybags]

Do it all in one line.

If Vblank is disabled (poke 54286,0) then the key debounce isn't done properly by the software and it won't detect consecutive keys that are the same.

[Allas]

I surrender nothing strange happens, maybe the NTSC system is different.