Pokey in FPGA?

[classics]

Since the address of the cartridge hardware is fixed it would not be plug-and-play compatible with anything. You would have to modify the program to see Pokey at a different address.

 

I just modified RMT using a hex editor by searching for the pokey memory addresses and replacing them with new ones, so its not very difficult, in fact I bet most software could be done automatically.

[Wilhelm]

Just a crazy idea, but you can install a switch in the atari computer to modify the CCTL line, using D5xx or D2xx.

 

that would give compatibility to the standard Pokey.

[Cybernoid]

You could do that, but the point is to make something that doesn't require a hardware mod. I wouldn't stop you from adding a switch. I can see how it could be done with one additional mux chip.

 

You could also make a PBI device that uses the whole address bus, that way you could decode the additional Pokeys at address $d200 and $d210. As long as you disable reads from the Pokeys on the PBI this should be okay...

 

However, it is easy to make a modified RMT player that uses the CCTL address space. Other programs could be modified as well.

 

I would also like to see a dual-sid cart for the Atari, and also a dual-sid/dual-pokey cart. Though, this last one will take up too much space in a cart.... it would be nice.

 

Heck, you could even do a pseudo-dolby 5.1 channel surround sound cart, but it would take 6 Pokeys!

[raster/c.p.u.]

If we put 2 pokeys into a cart and use A7 to select between the two... one at $d500 and the other at $d580, with a stereo jack...It should be easy to do for plug and play

Can I ask why there is used A7 ($d500/$d580) to select first or second pokey?

Why you don't use A4 so that there was first pokey at $d500 and second at $d510. It would be more similar to standard ($d200 for standard built-in pokey and 16 addresses below at $d210 is established location for second built-in pokey).

[Schmutzpuppe]

This guy seems to have build a pokey into a fpga:

http://home.freeuk.com/fpgaarcade/ast_main.htm

[Heaven/TQA]

unbelievable... sad that i have to clue what this hardware stuff is for... but it's amazing what is possible nowadays...

[Wrathchild]

I recall David Lloyd developing a SID (or maybe multi-SID) board during the early days of us trying to get the revised CC65 suite working for the Ataris at the beginning of 2000.

 

Maybe someone could contact him for details.

[classics]

Can I ask why there is used A7 ($d500/$d580) to select first or second pokey?

Why you don't use A4 so that there was first pokey at $d500 and second at $d510. It would be more similar to standard ($d200 for standard built-in pokey and 16 addresses below at $d210 is established location for second built-in pokey).

 

I guess A4 would be compatible with the idea posted about adding the toggle switch for external Pokey too, letting it automatically recognize it as a regular Gumby upgrade.

 

Changing it to A4 sounds like a pretty good idea.

[Wilhelm]

Maybe it could be easier to make PBI Pokey device rather than the Cartridge. There will be no need to add a toggle switch.

[Cybernoid]

I guess it would be possible to add some internal hardware that would allow any accesses to Pokey, Antic, Gtia, PIA, etc show up on the CCTRL address space. Make it configuratable be a $d500 register somewhere and you are set. This is a whole different discussion, though.

 

This would be most useful for adding extra Pokeys and Antics...if that is useful.