4 replies to this topic

[dwhyte]

I can't seem to find any info regarding POKEY programming on the 7800... I'm assuming it's not in the same spot as the 8bit AUDCTL($d200-$d2ff)

Another question... SIO access... for experiment purposes can a 1050 be hooked up to provide 90K or 130K of virtual memory... where would it be located... assuming not SIOV ($E459)

I haven't dived into the 7800 bios disassembly yet as these questions are the deciding factor in my attempt to start programming the 7800...


Thanks

p.s. by the way... Display List List? WTF was GCC thinking...

[dwhyte]

Disregard the last question... I did some searching and it seems the SIO was only on the 7800 keyboard, but then again, most of you probably already knew that...




I'll just go bang my head on the wall for asking a stupid question...

[Rybags]

Most programming considerations should be the same as the computers, although I don't know if the IRQ line is attached.

Clock speed is the same so music should sound the same.

[Bruce Tomlin]

I'm not sure about the IRQ line either, but it's not like there's any reason for it without the SIO hooked up.

But definitely the SIO is completely unused, and is more of an annoyance than anything. It would have been so nice if Atari could have made a 24-pin or 28-pin version without the SIO/keyboard support.

As to where to find it, it's mapped into the $4000-$7FFF block, with all bits but the lowest four being ignored. And then there's the Xboard, which is mapped to an unused 7800 address area, but you have to enable it first:

http://www.atariage....showtopic=74592
http://www.atariage....showtopic=82326

[DanBoris]

The IRQ is NOT wired up on the Pokey cartridges, but since there is an IRQ pin on the cartridge connector, it would be pretty easy to wire the Pokey IRQ pin to the cartridge pin.

Dan