Atari Chip compatibility with other systems

[seastalker]

I'm curious most specifically because I have lots of Commodore 64 chips and 1541 floppy drives laying around and wonder what ICs can be salvaged for a 800xl. Perhaps obviously not say the big guys like SID or VIC, but what about some of the smaller chips? Any existing list/database would be fun to compare Atari systems as well as other computers. if a rare pricey chip on ebay could be found more commonly in another system that would be useful like (hypothetically) if a MMU was also found in an Apple IIe.

 

Though it would be amazing to conceptualize a stereo/quad rig board of POKEY AND SID singing in harmony, I'll save that for another discussion day.

[Osgeld]

I would think anything common (like the 6532, or any glue logic) would be cheap and easy to find... cause they are common

Edited July 16, 2017 by Osgeld

[Rybags]

From the chipset SID is actually the most relevant and has been done. CIAs could in theory provide a more advanced IO solution than PIA does though not sure how much would be needed to have them as a replacement, and it would raise compatibility issues.

 

The problem with the old gear is the most of the system is reliant on running at the video or pixel frequency or some derivative of it, it's there that Atari and C64 differ since Atari is based on the NTSC colour clock but with C64 they decided on a higher base frequency (5/4 ratio?)

 

Regardless, VIC-2 provides stuff we just don't need again like refresh and I believe it also does Ras/Cas selection for the CPU which we don't want.

 

Back to SID - I think there are mixed implementations, the "true" way of doing it is using it's proper master clock speed which would mean that music would work properly, otherwise the notes would need to be recalculated. Running asynchronous clocks as such I believe requires extra interface hardware.