Sid-20 mod for the Vic

yoyodyne · Post by **yoyodyne** » Thu Feb 16, 2006 12:16 am

I've had these prototype boards that fit the vic sitting around, and
was wondering what to do with them, so I added a 6581 sid
chip to the vic-20.

I had to use an external 12v power supply to feed the sid, and I added
a regulator to keep it safe (not many 6581s around anymore!).
Maybe if I found a 9v sid, I could steal power from the user
port?

I finished putting it together tonight, and converted some of
my old (20 years!) basic sid programs to work. The sid sits
at $9800 (38912) so just change the s=54272 line to s=38912 and
my programs worked right away.

Its not very pretty yet:

http://home.alltel.net/bf63349/sid20.jpg

but it was built using parts I had (except for some capacitors I
bought at Radio Shack).

I would like to add a second sid to my 128d. Can any of you musicians
out there point me to some programs that use them?

Brian

vic user · Post by **vic user** » Thu Feb 16, 2006 5:27 am

nice one!

i love the pic.

chris

ruud · Post by **ruud** » Thu Feb 16, 2006 6:45 am

yoyodyne wrote:I had to use an external 12v power supply to feed the sid, ....

What about building the voltage doubler the C64 uses to generate 12V?

vic user · Post by **vic user** » Thu Feb 16, 2006 7:13 am

i found this voltage doubler info:

http://www.reconnsworld.com/power_voltdoubler.html

chris

carlsson · Post by **carlsson** » Thu Feb 16, 2006 7:28 am

Yoyodyne, this game is supposed to support a SID chip at $9140:

http://www.cbm.sfks.se/files/battleships.bin
http://www.cbm.sfks.se/files/battleships.doc

I suppose an internal mod is required to address some extra hardware in I/O block 1, since the cartridge port only has lines to blocks 2 and 3?

yoyodyne · Post by **yoyodyne** » Thu Feb 16, 2006 7:43 am

I thought about a voltage doubler, but the external
power supply was easiest last night.

Thanks for the link to the circuit!

Brian

GreyGhost · Post by **GreyGhost** » Thu Mar 09, 2006 6:50 am

Any chance of you putting a diagram of the curcuit on here for us to see?

Does it use an external speaker? What about using other sound chips?

Also, I have a Z80A CPU laying around. Could that be used by the Vic as maybe a co-processor or something. This stuff is a little out of my league, but I'm studying some electronics.(The talk about the reset switch and the debounce curcuit in another part of the forum got me intrested.)

Just curious,

saundby · Post by **saundby** » Thu Mar 09, 2006 10:15 pm

Yup, with the lines the Vic brings out it would be perfectly possible to add a Z-80. You could do it something like the CP/M cart for the C-64, but a bit more intelligently. See Ruud's site for info on that cart:

http://www.baltissen.org/index.html

-Mark G.

ruud · Post by **ruud** » Fri Mar 10, 2006 5:40 am

GreyGhost wrote:Also, I have a Z80A CPU laying around. Could that be used by the Vic as maybe a co-processor or something.

If you want something like a cart, you can forget it. The 6502 outputs its address line directly at the expansion port, just like the 6510 in the C64. But, unlike the 6510, the 6502 cannot be tri-stated. End of the story.

I could dream up a schematic that enables you to have a Z80 parallel to your 6502 but, with no software available, will it be worth the trouble?

Feel free to email me.

GreyGhost · Post by **GreyGhost** » Fri Mar 10, 2006 8:42 am

All just thoughts, like I said before I'm a novice to the max. Would a parallel application enable you to access both chips at the same time or just one or the other?

yoyodyne · Post by **yoyodyne** » Wed Mar 15, 2006 9:13 pm

GreyGhost wrote:Any chance of you putting a diagram of the curcuit on here for us to see?

Sure! Just give me some time to make something readable!

It was really simple, I can give a pin by pin description.

GreyGhost wrote: Does it use an external speaker?

I added a small circuit for the audio, but it duplicates what the
64 uses between the sid and the audio output. I have an
old amplified pc-speaker that I used for the sound. I imagine you
could use other sound chips besides the sid, but I haven't any to
mess with.

ral-clan · Post by **ral-clan** » Tue Dec 05, 2006 12:32 pm

Hi Yoyodyne and all.

Did plans for this SID add-on ever get made up? I've got the SID bug and a few extra experimenter boards (no SID chip yet though). I'd really be interested in building one of these SID-20 boards!

Centallica · Post by **Centallica** » Tue Dec 05, 2006 2:32 pm

ral-clan wrote:Hi Yoyodyne and all.

Did plans for this SID add-on ever get made up? I've got the SID bug and a few extra experimenter boards (no SID chip yet though). I'd really be interested in building one of these SID-20 boards!

You should of been at World of Commodore as Prophet54.com was there demoing their program to run off the SID...drool

Brian

ral-clan · Post by **ral-clan** » Tue Dec 05, 2006 2:49 pm

Yeah, I've been following the Prophet 64 project since before its release. VERY GOOD software. I'm so tempted, but I don't want to get into the whole other world of C64 collecting. I don't even have a C64, and have no room to set one up. Maybe if someone gives me one for free out of the blue one day I might buy this cartridge. But, as I said, VERY tempting.

That's sort of why I'd just like a SID cart for the VIC.

vic user · Post by **vic user** » Tue Dec 05, 2006 5:25 pm

I'm so tempted, but I don't want to get into the whole other world of C64

cue in the Star Wars music

Denial

Sid-20 mod for the Vic

Sid-20 mod for the Vic

Re: Sid-20 mod for the Vic

Z-80