Anyone connected an older sound chip?

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

Anyone connected an older sound chip?

Postby lorddoomicus » Nov Fri 10, 2006 10:27 pm

I found a source for 76489's. I was thinking, using a 6522, it sould be pretty easy to hook one up to the Replica.

Of course a SID chip from a Commodore would be cooler, but I think something simpler to start with like a 76489 is a better idea.

What does everyone else think?

-Derrik
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Postby kgreene » Nov Tue 14, 2006 6:29 pm

I have been considering hooking up an AY-3-891x chip to make a apple 1 version of the mockingboard. The programming was relatively straightforward (if somewhat arcane) so it seems likely that sound software from the II could be ported.
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Postby fsafstrom » Jan Tue 09, 2007 2:24 am

I tried hooking up the SN76489 Sound Chip straight to the Expansion bus and that didn't work... ;-)
The chip gives off some noise mixed in with a tone but whatever I send to it, nothing happens.
I had the Ready signal hooked up and that seem to halt the CPU now and then, I had to reset to get out of it...

Maybe I got it wrong, but this is how I hooked it up...
Image
I'm not crazy by the way, D0-D7 was reversed on the original Data sheet. :lol:

I tried to access it on address $C000 but nothing...

Data sheet:
ftp://ftp.whtech.com/datasheets%20&%20m ... N76489.pdf
Info:
http://www.howell1964.freeserve.co.uk/parts/76489.htm

Any ideas ???
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Postby vbriel » Jan Tue 09, 2007 8:13 am

Try PHI2 to the clock, everything is timed memory addressing wise around PHI2. PHI1 is 180 degrees off. And what do you have READY tied to? You might just let that hang for now, that is an output ready pin on the sound chip. If anything it goes to RDY but I would be careful of that since that can stop the CPU. While running, test the value of that lead with a volt meter. Since it pulls low when active I would put a pullup resistor on that if you do tie it to RDY.

Also, the MSB is LSB is backwards so D7 is actually D0. Wow, thats bassackwards.

Never used this chip so I can't tell you. The audio out looks like it can go straight to powered PC speakers no problem. Keep trying.

Vince
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Postby fsafstrom » Jan Tue 09, 2007 12:50 pm

Hmm, same problem with Phi2...

I'm going to hook this chip up to a micro controller and give it a try.
Let me see if I can get it to work in a more familiar environment before I hook it up to the Replica gain...

It's cheaper to try it out on a $4 microcontroller rather than the Replica just in case something goes wrong... 8)
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Postby vbriel » Jan Tue 09, 2007 3:28 pm

That's what I would do. Did you also wire up D7-D0, D6-D1, D5-D2...? Because the one web site stated that they used D0 as the MSB for some reason.

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Postby fsafstrom » Jan Thu 18, 2007 5:06 pm

I don't really have energy to figure this out but it would be nice to have a working configuration...

If you think you can get this working, send me a Private Message with your address and I'll send a chip to you.
Only thing I'm asking in return is that you give it an honest try and if you get the SN76489 chip to work, let us know how you did it... 8)

Note that I got these cheap off E-bay so there could be a possibility that these chips don't work at all... :(
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Postby Mojoseph_12 » Jul Sun 22, 2007 3:49 am

I think I got the SN76489AN to work. I connected the /WE and /CE both to $B000 so nothing is connected to R/W.Nothing to Rdy.I added a cap between Vcc and Gnd to cut down on noise from the power source. When I write to $B000:F0 00 the sound changes $B000:80 12 makes a new sound. :D

There is some random noise when it is powered maybe because of some random data inside the SN76489AN. But it changes when new data is sent to the IC.
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Postby Mojoseph_12 » Jul Fri 27, 2007 4:35 am

I found this picture of connecting the SN76489 to a microprocessor
Note:I edit the data bus to the correct lables.

http://www.flickr.com/photo_zoom.gne?id=914062356&size=o

when I solder the IC to a pcb i didnt realize I made a solder bridge between the ready and /WE and not /CE so the IC made sound and was programmed. The link shows a good way of connecting it to the replica 1 using an AND gate. I am going to try it later and see if it works. :)
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Postby Pepe » Oct Fri 12, 2007 7:52 am

Did anyone get this to work ? The last schematic looks a bit dangerous as it relies on the READY-signal to latch the data into the device, but it might work.

You can also gate (NAND) the inverted R/W signal from the CPU with PHI2 and connect to WE* and have a chip select signal connected to CE*. This way the data should be latched into the device when WE* is asserted, assuming that the READY signal has been negated. The SN76489 seems to have a strange asynchronous bus design which is probably what is causing your problems.

/Pepe
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