you can use 16mb for rom, but there is no point doing that for various reasons. Explained in PM.

In order to use a 32mbit (4mb ) you need extra adress lines , RA20-RA21(wich in reality are RA19 and RA20), these 2 lines are asserted to GND because they are not used in a 8mbit memory. These lines work as adress lines when you have !ROMCS selected (or low level), You can use 4 32mbit memories controlled by this line along with bank select. at the trailing edge of reset they they act as inputs and if they are high level they have other functions.(multiplexed lines). I don't see the point of using it. I think 8mbit is just fine. Let people play with Dram on simm72 connector.
In my humble opinion, I wouldn't even put the soj memory, I would put just the simm socket and that's it. 1mb rom and 16 mb ram, simple. Remember, that there are no 32mbit or higher woking with 5V ,or if there are , they must be obsolete, so it would also need level translators, wich would make the board bigger and more expensive.

Do you have a picture of the proto type board? When everything is soldered on.

So far there's only a paper prototype as well as 3 commercial interwave based GUS cards I used for research.
Prototype will happen soon-ish tho.

Judging from the derived pinout the DIP-footprint for the ROM used on the GUS PnP appears to be for the 27c800 type EPROM
http://www.arcadiabay.de/images/elektronik/ep … c800_pinout.png

I've posted a link to this thread to a Russian forum asking for help with ROM-related issues, no relevant comments so far, but still one member pointed at a "widely spread mistake in the layout: the crystals are located too far away from the IC they serve. Crystals as well as inductors should be placed at 90 degrees to each other, especially when crystals are soldered adjacently to each other. The matter consists in the direction of traces and their interference from the neighboring crystal's traces."

Yeah, tthe crystals are pretty much the last major loose end in the design currently. Attempted moving them a bit at one point to clear up space for the SIMM72 but probably will go back to arranging them the way they were on the PCA761AW.
Someone paid really close attention there 😀

I'll also upload part of the schematic later on already ... so (if anyone wants) a programm for reflashing the Wavetable ROM can be written - allowing alternative ROMs and initial programming in circuit (as of now the ROM chip needs to be written in an external programmer before soldering it to the board).

@hard1k, please read my answer regarding the use of 16mb as rom. As far as using crystals and inductors on that layout, we don't know. Maybe internal design of chip has emi protection . We should use 4 layers boards ,with power planes also.

A 4 layer board would make the PCB twice as expensive, so unless that can't be prevented I see no reason to take that approach.
The crystal layout shown is copied almost 1:1 from the GUS PnP - so it "should" work. I'll try to revert it to the PCA761AW layout as best as I can tho.

EDIT: ROM related parts of the schematic

This is confusing. memory datasheet goes from A0 to A18 but on datasheet it's RLA1 to RLA19, being RA20 and RA21 multiplexed I/O (inputs at trailing edge of reset) and after that become outputs RLA20 and RLA21.

EDIT: Actually ... due to all InterWave cards doing a pretty "meh" job on the crystals I'll go with the GUS PnP approach never the less for the prototype and actually check the signal integrity using a scope.

Here's a close-up of the relevant parts ... placement of caps and crystals will be swapped so slightly shorten the signal lines:
http://i.imgur.com/4wA2FAP.png

Wow, this is a really impressive project and I'm certainly interested in this! I've been wanting a Gravis Ultrasound card for sometime now, and this project is pretty amazing! 😀

Keep up the great work! 😎

Marmes wrote:

@hard1k, please read my answer regarding the use of 16mb as rom.

Yeah, I read it. I don't see any use for 16mb of ROM, but for 4mb - yes. If the original 4mb patchset can be flashed to the ROM without any changes, that would definitely be a great advantage of ARGUS over all other InterWave boards.
So I think the major obstacles are software-related (i.e. the ROM image structure and the ROM configuration utility), and the address lines can be solved, I guess.

Edit: did you mean your answer in the thread? I've noticed your post about some answer in PM, but if it was intended for me, then I should say I haven't received any PM from you recently 🙁

An interesting point would be of course if one could convert a patch set (or FFF file) to a working ROM image for flashing.
However it would be only useful if MegaEM could use it, because games usually run one of these three approaches:
- use the card as GUS classic with own patch handling (UltraMID, Miles AIL), with max. 1 MB RAM per song organized by the driver.
- use the card as GUS PnP with own patch handling or large GUS PnP soundfont
- use General Midi
-> from within Win9x you have MPU-401 emulation which allows to use a large GUS PnP RAM soundfont
-> from DOS with MegaEM which goes for the default 1 MB ROM of the GUS PnP.

So the ROM is only used in the last case where you have a game/application that runs with (Q)EMM386 loaded, does not run in a Win9x dosbox, can not be patched for native GUS.

Set the case that a 16 MB ROM would be possible and MegaEM could make use of it, then you could choose General Midi instead of GUS classic in a games setup expecting a better music quality. The same can be achieved already by using the MPU401 emulation within Win9x.

In that case instead of putting a flash directly to the board, maybe a connector with enough pins to connect to flash controller would be the answer for the purpose of testing.
But it that case I would prefer to use a WT connector and use a db50xg or a roland.

hard1k wrote:

Yeah, I read it. I don't see any use for 16mb of ROM, but for 4mb - yes. If the original 4mb patchset can be flashed to the ROM […]
Show full quote

Marmes wrote:

@hard1k, please read my answer regarding the use of 16mb as rom.

Yeah, I read it. I don't see any use for 16mb of ROM, but for 4mb - yes. If the original 4mb patchset can be flashed to the ROM without any changes, that would definitely be a great advantage of ARGUS over all other InterWave boards.
So I think the major obstacles are software-related (i.e. the ROM image structure and the ROM configuration utility), and the address lines can be solved, I guess.

Edit: did you mean your answer in the thread? I've noticed your post about some answer in PM, but if it was intended for me, then I should say I haven't received any PM from you recently 🙁

That would be nice , but in terms of cost it would be rather expensive. Because we would need 4 32 mbit that could support 5v, or we would need to add level translators. 32mbit we could put am29f032 wich would support 4mbytes. I am in favour of leaving things as they are. I would remove the soj ram and just use simm memory and 1mb rom. Saves space and money 😀 Argus would be great like this. Simple .

elianda wrote:

An interesting point would be of course if one could convert a patch set (or FFF file) to a working ROM image for flashing. Howe […]
Show full quote

An interesting point would be of course if one could convert a patch set (or FFF file) to a working ROM image for flashing.
However it would be only useful if MegaEM could use it, because games usually run one of these three approaches:
- use the card as GUS classic with own patch handling (UltraMID, Miles AIL), with max. 1 MB RAM per song organized by the driver.
- use the card as GUS PnP with own patch handling or large GUS PnP soundfont
- use General Midi
-> from within Win9x you have MPU-401 emulation which allows to use a large GUS PnP RAM soundfont
-> from DOS with MegaEM which goes for the default 1 MB ROM of the GUS PnP.

So the ROM is only used in the last case where you have a game/application that runs with (Q)EMM386 loaded, does not run in a Win9x dosbox, can not be patched for native GUS.

Set the case that a 16 MB ROM would be possible and MegaEM could make use of it, then you could choose General Midi instead of GUS classic in a games setup expecting a better music quality. The same can be achieved already by using the MPU401 emulation within Win9x.

Not sure if this was asked before yet... but how difficult would it be to add support for 8-bit ISA slots?
From what I know, the GUS needs 16-bit IO for some things to work, which is why the original GUS doesn't work in anything lower than a 286 with 16-bit ISA slots.
But... XT-IDE cards solve basically the same problem with some simple latches to regroup 8-bit reads/writes to 16-bit reads/writes.
Would it somehow be possible to do this for the GUS as well?
It doesn't matter if it isn't backward compatible with existing software, because there probably isn't any software out there that uses a GUS and still is 8088-only code.
But it would give the 8088 demoscene a new toy to play with, allowing high quality mod playing at virtually no CPU usage on 8088 for the first time. Opens up interesting possibilities 😀

Marmes wrote:

That would be nice , but in terms of cost it would be rather expensive. Because we would need 4 32 mbit that could support 5v, or we would need to add level translators. 32mbit we could put am29f032 wich would support 4mbytes. I am in favour of leaving things as they are. I would remove the soj ram and just use simm memory and 1mb rom. Saves space and money 😀 Argus would be great like this. Simple .

I'd rather have the SOJ than the SIMM, really. For those wanting nothing more that GUS classic compatibility this would allow one to not even solder the SIMM slot.

EDIT: Fixed the quote

Both the SOJ and SIMM72 have their unique rights to exist. I guess the SOJ is cheaper and offers a basic RAM setup, while the SIMM72 is for those wanting a card as maxed out as possible. Combining both offers a comfortable way to have almost full power over the bank sizes (1MB per bank is missing or needs placing a 4MB SIMM).

About 8bit support - that's a perfect question for the datasheet and programmer's guide.
Also ... do any 8088 based systems support PnP?