Hi!
I only read 2 of them

So what is the exact memory layout going to be? (it is not 100% clear for me from the blog)

- There will be 2x 256 kB SOJ onboard, which will give compatibility as 512 kB GUS classic (2 banks a 256 kB)?
- with the Jumper the memory bus can be switched to the SIMM72 slot. There I can plug a 16 MB SIMM72 which will result internally in 4 banks with 4 MB each = 16 MB. This results in 1 MB GUS classic compatibility as well?
- Jumper can as well disable all RAM
- ROM will be the default 1 MB

Is there a design barrier that prevents using 2x 512 kB SOJ by default to have 1 MB GUS classic compatibility in the standard config?
It is just that in regards of games the card is used 99% as GUS classic, where the best quality can be achieved with games loading patches dynamically according to the 1 MB profile.
Is the ROM an actual ROM or some kind of Flash where also other content can be dropped. I know that atm no other ROM exists, but does that mean different ROMs can't be made? MegaEM is limited to 1 MB ?!?

Each SOJ is 512kb, offering 2 banks of 256k - so in case both footprints are populated you get 1MB for a fully blown GUS classic compatible setup without having to use (or even populate) the SIMM72
Otherwise your observations are correct.

About the ROM - I'm currently closing in on that area. According to the datasheet up to 16MB of ROM can be adressed.

EDIT: ROM is working on the PCA761AW again ... turned out one of the latches had become bad. Gonna attach Marmes Flash-ROM next and see if that approach works 😀

EDIT2: 29F800 isn't detected 🙁

EDIT3: Lifting Pins 44/43 didn't help either - reverified everything is working by resoldering a IW78C21M1, which it is. Crap!

EDIT4: Contacted Macronix for a datasheet on said chip - maybe I'll get lucky.

pins 43 and 44 are not used on iw78c chip. but they are used on 29f800

Anyone know any software that works with the InterWave native mode that doesn't require any RAM on the card?
I'm in the progress of reviving a Reveal WavExtreme 32, which might come handy in reversing the ROM, but can't thoroughly test the card as of now.

It was previously broken but so far I got the PnP-ROM accessible again, the card passes the GUS PnP setup and can play back digital sounds under windows 3.11 - I didn't get to test midi/megaem stuffs yet as the card doesn't have a IW78C21M1 currently 😉
Inertia Player, XTC-Play & cubic player sadly don't detect the card.

EDIT: Also macronix replied:
"The IW78C21M1 is EOL product, so we don't support any more."
*clap*clap* that was helpful.

Guess what? Pictures say more than a 1000 words 😀

FlashROM substitute is now working 😀 (turned out the PCA761AW kept the ROM in a constant reset state ... which can be easily fixed)

P.S.: Dear Macronix, for being so super helpful I'd like you to have intercourse with a cactaceae.

That may be one of the coolest photos to have appeared on Vogons 😀

Very cool indeed. Well done shock__.

Excellent work! 😀

Great milestone achieved! Really happy to hear that! 😀

Nice to see it going 😀

Major props to Marmes for figuring out the pinout, reading the IW78C21M1 and donating the programmed 29F800 that was used for experimenting.

Seeing how the substitute is almost the same pinout as the original chip, do we really need a second, DIP-sized footprint for an alternative bank? As things are I'd add a single jumper to represent the difference in pinout instead. Which would mean only 1 bank contrary to the proposed 2, but also more PCB space for another feature (maybe reprogramming the Flash-ROM in circuit?)

Well, there is one major issue that needs to be addressed in that respect - does the internal structure of the ROM image match the FFF file structure? I mean, can we take an FFF patchset and flash it into the ROM? If yes, then a DIP footprint would be *extremely* useful as it will allow for custom 4 MiB chips to carry the original Voice Crystal 4 MiB patchset. If no (and there is no way we can accomodate the originally RAM-intended patchset for use as ROM image), then there is actually no use for any footprint other then the original one - just because we'll be limited to the original 1 MiB image from the IW78C21M1 chip.

To be perfectly honest - I have no idea how the ROM image is built up (and wouldn't know how to start analyzing) and since I can't freely distribute it (copyright and stuff) there's little chance we might see a 4MB ROM bank for now. Least I can say is that the ROM image also contains SBOS patch information, so I guess it's a little more than just a .fff bank.
DIP footprint would be limited to 1MB by hardware anyways (16 data lines, 19 adress lines) - sadly the datasheet doesn't mention how exactly the 20th line for a 4MB bank is latched/designed. It's kinda funny how the RAM-Adress lines become the upper Data-lines for the ROM and stuff (that part even is wrong in the datasheet but correct in the programmer's guide).

Me neither. I guess the only way to find out is to flash the 4 MB file into the Flash IC and try it (provided that someone can advise on the addressing issue; some description of addressing pins is given in Table 5 on page 9 of the attached datasheet).
Another bottleneck will be software-related: InterWave needs to be configured by software for the correct size of installed ROM. I guess this won't be a great problem, but still some piece of software will have to be written if we want to use 4 MB ROM.

But if nobody can explain how to bypass all of the above - then yes, no additional footprints will be needed... 🙁

Better refer to page 354 (A-4) of the programmer's guide. That table is wrong in the datasheet (blocks MA0:2 & MA3:10 are backwards).

On another note ... I'll get back into contact with Eye & I Sound Design about end-user licensing their sample data and designing a .diff file to create a ROM image from their data, so folks can get down to analyzing if they want before the hardware gets finalized (as said I'd have no clue how to get started ... and don't think it's something I'd enjoy too much myself).

shock__ wrote:

Anyone know any software that works with the InterWave native mode that doesn't require any RAM on the card?

I think that Miles Sound System does support IW native mode with IWSBOS loaded, even without RAM present.

Excuse the dumb question at this point, but the card as-is with some ram in the socket, isn't it compatible with the GUS-classic?

keropi wrote:

Excuse the dumb question at this point, but the card as-is with some ram in the socket, isn't it compatible with the GUS-classic?

It is compatible. But the cards without any RAM are not compatible. They need direct Interwave support.

^ thanks for the clarification 😀