My Vicious sound card project

What have you built or do you want to design to go with your replica 1

My Vicious sound card project

Postby speltone » Apr Sun 06, 2014 2:35 pm

Hi everybody!

I've been developing a SID based sound card for the Replica 1 (and I guess for the Apple 1 in general) for the last month or so. Today I got a rudimentary SID player software so much into working order that I was successfully able to play the Commando tune with my card. Some SID tunes may require more C64-like environment than others so it may be impossible to make all of them to work. None of them will work out of the box starting from the fact that in C64 SID chip is visible in the address which is occupied by PIA in the Apple1.

In addition to SID chip the card houses a CIA chip for timed interrupts and there's also place for ROM where I intend to put some relevant software like the SID player. I just currently don't have any PROMs (or PROM burner for that matter) so the ROM is not yet mounted. The card requires only 5V power line. The SID chip 6581 needs 12V but thats generated on the card with a DC-DC converter. Works quite well, though I'm not sure if that conversion contributes for any of the digital noise which is clearly audible from the audio out line. AFAIK in the C64 SID uses it's own separate regulated power line to minimise the digital noise. That could be a possibility here also but I haven't tested that yet.

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Sampo
Attachments
ViciousProtoA.jpg
Vicious A-1 Sound Card Prototype A
ViciousProtoA.jpg (107.14 KiB) Viewed 5288 times
speltone
 
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Joined: Mar Tue 04, 2014 4:18 pm
Location: Espoo, Finland

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