Covox Sound Master Reverse Engineering / Replica

Discussion about old sound cards, MIDI devices and sound related accessories.

Re: Covox Sound Master Reverse Engineering / Replica

Postby SquallStrife » 2014-8-28 @ 22:57

Re: Tandy music on a card: viewtopic.php?t=31040

It wouldn't work in AT or above systems because of the 2nd DMA controller.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby carlostex » 2014-8-28 @ 23:22

SquallStrife wrote:Re: Tandy music on a card: viewtopic.php?t=31040

It wouldn't work in AT or above systems because of the 2nd DMA controller.


Ah, right i totally forgot about that. But emulation should be possible. There is a TSR named TEMU, that emulates tandy on a covox speech thing. I wonder if we can take DOSBox source code and emulate tandy via a Sound Blaster DAC on a DOS environment.

If so this tandy discussion should be done in another thread.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby Cloudschatze » 2014-8-28 @ 23:22

carlostex wrote:...i'm afraid most of the games would require Tandy graphics to get Tandy Sound as well.

Actually, the majority of games that I've tested (from the larger publishers) provide command-line switches and/or configuration options to allow for Tandy sound + EGA/VGA/etc.

SquallStrife wrote:Re: Tandy music on a card: viewtopic.php?t=31040

It wouldn't work in AT or above systems because of the 2nd DMA controller.

That conflict can be managed. Assuming there isn't concurrent use of the 16-bit DMA channels, one option would be to stick the Tandy card at 1E0 (where it's at in the 2500-series and 1000 RSX besides), and re-direct the C0-range writes via TSR, similar to how SoftMPU operates.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby swampfox » 2014-8-28 @ 23:35

Yvan256 wrote:GAL16V8-25LNC (x1) (whoever can contact someone who used to work at Covox try and see if we can get the programming information needed for that one)


Well, I found this: http://doc.chipfind.ru/lattice/gal16v825lnc.htm

If no one from Covox has any information, perhaps one could contact someone from Lattice Semiconductor?
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Re: Covox Sound Master Reverse Engineering / Replica

Postby carlostex » 2014-8-28 @ 23:44

swampfox wrote:
Well, I found this: http://doc.chipfind.ru/lattice/gal16v825lnc.htm

If no one from Covox has any information, perhaps one could contact someone from Lattice Semiconductor?


That's just the datasheet of the IC. We need the logic that was programmed on the GAL by Covox.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby Stiletto » 2014-8-29 @ 02:11

If it's like PALs, it could be possibly be dumped by someone with a PAL dumping rig. Usually this is a few members of the crew known as "The Dumping Union" who specialize in MAME/MESS dumps. That's who I'd contact for help, anyways.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby carlostex » 2014-8-29 @ 08:34

Cloudschatze wrote:Actually, the majority of games that I've tested (from the larger publishers) provide command-line switches and/or configuration options to allow for Tandy sound + EGA/VGA/etc.


Great news then.


Stiletto wrote:If it's like PALs, it could be possibly be dumped by someone with a PAL dumping rig. Usually this is a few members of the crew known as "The Dumping Union" who specialize in MAME/MESS dumps. That's who I'd contact for help, anyways.


GAL's are much easier than PAL's. If i'm not mistaken, GAL's work similar to EEPROM's. You store or erase the logic via Vcc.

The challenge here is to find the actual logic that was programmed in the GAL. In my opinion if we want this project to walk forward and the clone card to be a reality we have no choice but to dump the GAL's from the original cards. This envolves de-soldering the GAL or connection wires to the correct legs and the IC programmer.

I would do that job except i don't own a card. Since Yvan has a degree in electronics i assume he'll be comfortable dumping the GAL. The question is that if he is comfortable de-soldering the GAL or connecting wires to the GAL on the card. I actually think de-soldering has a much smaller risk.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby keropi » 2014-8-29 @ 10:23

99.999% the GAL/PAL/whatever has the READ PROTECTION bit to ON , so putting it in a programmer produces no result... sadly it needs other methods to read the data - expensive in both knowledge and money...
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Re: Covox Sound Master Reverse Engineering / Replica

Postby Yvan256 » 2014-8-29 @ 12:42

Let's wait until I trace the card and its ICs, if we're lucky maybe the GAL was only used for the digital joystick ports?

After that, I already have an ISA protoboard card, what I'd need is a spare AY-3-8930.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby vetz » 2014-8-29 @ 13:18

I'm going to order some stuff from Taobao. I dont mind ordering one of the AY8930 I linked to earlier and send it to someone who needs it. Its so little amount of money that its not the biggest loss if it turns out to be something different
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Re: Covox Sound Master Reverse Engineering / Replica

Postby carlostex » 2014-8-29 @ 15:06

vetz wrote:I'm going to order some stuff from Taobao. I dont mind ordering one of the AY8930 I linked to earlier and send it to someone who needs it. Its so little amount of money that its not the biggest loss if it turns out to be something different


That would be deeply appreciated. Since Yvan volunteered to clone the board, i'd suggest you 2 get in touch.

This is an excellent tutorial on how cloning PAL/GAL's.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby Yvan256 » 2014-8-29 @ 15:17

vetz wrote:I'm going to order some stuff from Taobao. I dont mind ordering one of the AY8930 I linked to earlier and send it to someone who needs it. Its so little amount of money that its not the biggest loss if it turns out to be something different

Could you order five? I could use backups in case something goes wrong and if all goes well, I'll have enough to make five boards to send to others.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby Great Hierophant » 2014-8-29 @ 16:36

carlostex wrote:Welcome to VOGONS Yvan!!! Thank you for coming here. I had to contact Trixter to get in touch with you.

First of all, a non-DAC Tandy sound card would be amazing, but i'm afraid most of the games would require Tandy graphics to get Tandy Sound as well. So i'm not sure how well that would work. But with some "magic" it should be possible and and incredible addition to our retro machines.
Combining all three, not so much.

Yvan256 wrote:GAL16V8-25LNC (x1) (whoever can contact someone who used to work at Covox try and see if we can get the programming information needed for that one)


Crap i was afraid of this. I seriously doubt someone from Covox would give us the logic or even find it for that matter. Dumping would be a last resource measure, but necessary i'm afraid....

BTW, it would be nice to have high resolution pictures of the card...


For the GAL, perhaps the easiest thing would be to try and dump it, and if the security cell is active, then use the instructions given here : http://www.vintage-computer.com/vcforum ... AL-(Part-1)

For many games, Tandy sound will not be used without Tandy graphics, or you may get a black or garbled screen. In other games, Tandy sound will not be used because the system is detected as a PC, not a Tandy 1000. A BIOS replacement would be required.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby keropi » 2014-8-29 @ 19:40

well if someone here can clone/read/whatever a GAL then try this as well: viewtopic.php?f=46&t=38478 so the intelligent-mpu situation can be solved once and for all for everyone :)
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Re: Covox Sound Master Reverse Engineering / Replica

Postby Stojke » 2014-8-29 @ 19:44

Can't we simply try to find the people who worked on such things and ask for their assistance?
There are 3 models besides Roland who are intelligent.

If GAL chips require serious work to be decoded than we might as well search for those people too.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby Yvan256 » 2014-8-29 @ 21:34

I have only taken a quick look at it, but aren't GALs relatively simple? They have input and output pins, and the outputs change depending on the inputs? They're only complex, programmable 74HC138, as far as utility goes? That's only 256/512/1024/etc combinations to try out, isn't it?
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Re: Covox Sound Master Reverse Engineering / Replica

Postby carlostex » 2014-8-29 @ 21:55

Yvan256 wrote:I have only taken a quick look at it, but aren't GALs relatively simple? They have input and output pins, and the outputs change depending on the inputs? They're only complex, programmable 74HC138, as far as utility goes? That's only 256/512/1024/etc combinations to try out, isn't it?


Oh yeah they are simple, but if they are read protected additional work is required to get the logic out of them. If ChuckG's guide is clear to you than it shouldn't be a big problem.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby Yvan256 » 2014-8-29 @ 22:39

carlostex wrote:
Yvan256 wrote:I have only taken a quick look at it, but aren't GALs relatively simple? They have input and output pins, and the outputs change depending on the inputs? They're only complex, programmable 74HC138, as far as utility goes? That's only 256/512/1024/etc combinations to try out, isn't it?


Oh yeah they are simple, but if they are read protected additional work is required to get the logic out of them. If ChuckG's guide is clear to you than it shouldn't be a big problem.


You don't need to get the logic out of them, you just probe them to see what they do. Protected or not, they have to do their job. ;-)

If they're really as simple as a 74138, in that it was programmed as an address decoder of some sort, all it's going to take is connecting the pins, make a small circuit, connect to a parallel port and write a small program to test all possible combinations.

edit: I just read this in the datasheet: "In addition, 100 erase/write cycles and data retention in excess of 20 years are specified." Uh-Oh... We could be around five years too late.
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Re: Covox Sound Master Reverse Engineering / Replica

Postby vetz » 2014-8-29 @ 22:58

Yvan256 wrote:
vetz wrote:I'm going to order some stuff from Taobao. I dont mind ordering one of the AY8930 I linked to earlier and send it to someone who needs it. Its so little amount of money that its not the biggest loss if it turns out to be something different

Could you order five? I could use backups in case something goes wrong and if all goes well, I'll have enough to make five boards to send to others.

Sure, NP :) One of them goes into my card if this project comes to a successful end :cool:
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Re: Covox Sound Master Reverse Engineering / Replica

Postby awgamer » 2014-8-29 @ 23:03

Yvan256 wrote:
carlostex wrote:
Yvan256 wrote: edit: I just read this in the datasheet: "In addition, 100 erase/write cycles and data retention in excess of 20 years are specified." Uh-Oh... We could be around five years too late.


If your card is still working, it would seem to follow it has retained the data.
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