Re: FMonster, the monster of sound synth

Posted on 2018-08-12, 11:34

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

AD7528 is just 2 AD7524, they should have exactly same ouput quality. Probably. But those have different packages and somewhat different reference schematics (connections of AGND/DGND). And 7528 can not write to both channels at once. I'll try three variants: 1) 2xAD7524 in reference variant 2) …

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Re: Covox Sound Master Reverse Engineering / Replica

Posted on 2018-08-09, 23:43

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

I am still willing to contribute (I own the card). I hope it is possible to reverse engineer the card without having to desolder anything. And if we have to, well that would also be ok for me. If you have any suggestions to keep the project moving forward go ahead... At the moment I have all the …

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Re: FMonster, the monster of sound synth

Posted on 2018-08-09, 23:24

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

I am still willing to contribute (I own the card). I hope it is possible to reverse engineer the card without having to desolder anything. And if we have to, well that would also be ok for me. If you have any suggestions to keep the project moving forward go ahead... Do you mean Covox Sound Master? …

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Re: FMonster, the monster of sound synth

Posted on 2018-07-26, 22:05

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

Here is some more "shrinking progress". SSI-2001 block and clock generation block (for the whole card). Before: ISSI_2018-07-18_01.png After: ISSI_2018-07-18_02.png That's 33 mm less length! And jumpers also had been moved to the top edge of the board. And here is my current variant for automatic …

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Re: FMonster, the monster of FM synth

Posted on 2018-07-26, 19:48

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

What i'm hoping is that shock__ can have access to moturimi1 's card and help Fagear with tracing what's left to be traced. That's not everything that needs to be done though, there is a PAL chip on the Covox Sound Master that needs to be probed and then its function replicated either by a GAL or …

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Re: FMonster, the monster of FM synth

Posted on 2018-07-25, 20:55

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

That was a specific design choice, because the PCjr has the same address decoding to C0-C7. I believe the same goes for Tandy. Yes, I know. Those just don't decode 3 LSBs. But it is not necessary, PSG has just one register, that should be at 0x0C0. At least I didn't see any software, that was …

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Re: FMonster, the monster of FM synth

Posted on 2018-07-25, 14:45

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

i also tried with a flipflop but the bios enabled it during boot because of 0c0h are the second dma controller. thats why i switched to mcu. i wanted to keep it very simple :) it worked well with other adresses. Would you even use Tandy on port 0x0C0 if you have DMA there? Also, were those writes …

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Re: FMonster, the monster of FM synth

Posted on 2018-07-25, 13:16

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

This is not PSG, PSG is a Chip with DAC and 3 Voice. How do you call that chip then? "Tandy 3-voice Synth", "Tandy 1000/PCjr-like Synth" is far too long. i simply mute the amp with the attiny13, but you can also just cut the output with the same firmware e.g. using a opto coupler like dreamblasters …

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Re: FMonster, the monster of FM synth

Posted on 2018-07-24, 22:38

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by Fagear

in Marvin \ Sound

in Marvin \ Sound

Thank you everybody for information about OPL IRQs! I've left IRQ jumpers for OPL2 in place, because there is no gain in their removal (nothing usefull will fit in empty space). And I'm not planning to add IRQ jumper for OPL3 block. For the moment I'm reading through the thread about Tandy PSG while …

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Re: FMonster, the monster of FM synth

Posted on 2018-07-24, 12:27

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

The AdLib never had the IRQ line connected to the OPL2 (the interrupt flag of the OPL2 can be polled by reading 0x388, the top 3 bits indicate the timer irq status). I don't think any OPL3 card has it connected either. At least the common Sound Blasters and clones do not. Is there any software that …

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Re: FMonster, the monster of FM synth

Posted on 2018-07-24, 11:41

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

On SBPro 1, AFAIK, only 2 ports at 388-389 range are used, but 4 ports at 220-223 range. A value written to 338 gets duplicated into 220 and 222, so both OPL2 chips receive the same data and operate synchronously and only way to used them separately and obtain stereo audio is to use 220-223 (sb_ …

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Re: FMonster, the monster of FM synth

Posted on 2018-07-23, 21:20

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

Recently discussed here. https://www.vogons.org/viewtopic.php?f=62&t=58936 As I can understand - it is always 4 ports for "native" OPL3. Or 2 ports in "OPL2 mode". I found this nice document with details for Creative cards. Interestingly, while it does seem to support Scali's assertion that …

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Re: FMonster, the monster of FM synth

Posted on 2018-07-20, 22:05

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

The Ad Lib Gold, arguably the card that set the standard for OPL3, did exactly that: the OPL3 was at 388H through 38BH by default, with nothing at or near 220H. ... but I remember specifying 388H for OPL3, even after moving to a Sound Blaster 16. I think I will stick to AdLib/SB16 compatibility. So …

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Re: FMonster, the monster of FM synth

Posted on 2018-07-18, 19:14

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

If there are concerns around such a large 8-bit ISA board (warping, cost, installation etc.) Warping - we'll see later. Cost - definitely will be BIG. Installation - it will fit almost any BabyAT case I think. And it will consume only one slot, so it would be easy to choose which one. have you …

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Re: FMonster, the monster of FM synth

Posted on 2018-07-18, 08:52

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

What about disabling single card parts ? Will you add switches add the backpanel ? That is easily accomplished by pulling off jumper that set address for each block. This effectively disables "Chip Select" line of corresonding block. Maybe I'll manage to put them all in a convinient place - it's …

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Re: FMonster, the monster of FM synth

Posted on 2018-07-18, 08:06

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

The term "FM" only refers to the Yamaha OPx chips, at least on PCs. Tandy 3-voice, CMS and SID are not "FM". You are right, I've used incorrect terminology. Let me rephrase that. All of those are frequency synths with different types of modulations. Some have primitive amplitude modulation (for …

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Re: FMonster, the monster of FM synth

Posted on 2018-07-17, 22:10

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

Tree Wyrm wrote: I kinda wonder about having both OPL2 and OPL3 on same board, unless some pins/switches to put them on different addresses. One of those thing that have to be researched yet. As I understand for now, default address for AdLib was 0x388. And for SB16-compatible OPL3 it was 0x220.

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Re: FMonster, the monster of FM synth

Posted on 2018-07-17, 21:53

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by Fagear

in Marvin \ Sound

in Marvin \ Sound

keropi wrote: ^ I think something like ~31-32cm ? 31 cm for PCI and 33,5 cm for ISA board as I found now. That is already a minor problem, but I'll try to squeeze layout into that size.

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Re: FMonster, the monster of FM synth

Posted on 2018-07-17, 21:13

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by Fagear

in Marvin \ Sound

in Marvin \ Sound

keropi wrote: I approve of this. Maybe using a sop YM3812 will save some space , it would be great if this was not a 100% full-length card By the way, what is the limit for "full-length card"? 😅

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Re: FMonster, the monster of FM synth

Posted on 2018-07-17, 20:46

by

by Fagear

in Marvin \ Sound

in Marvin \ Sound

That thing will be a behemoth! I hope that it WILL BE at least... But the main advantage is that it will rule them all - and alleviate much of the need to add/remove cards constantly in my retro rig. That one of the goals. It would be cool to have "all-in-one" FM Synth board with proper MPU-401 and …

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