I am sure this is revisiting some old QuestStudios forums discovery (and some USENET discovery before that), but I hadn't seen things explained this way recently.

Some days ago, a friend of mine asked if I'd ever stumbled upon datasheets or even pinouts for Gravis Ultrasound's main chip, the ICS1614 / ICS11614 / GF1 / GF-1.
Apparently a buddy of my friend was looking to get into designing a new audio board and repurposing some scavenged chips.

And I had to reply that "no, I hadn't" - I still haven't seen official GF1 documentation leaked. Just that SDK and stuff...

Still, it got me thinking.

The GF1 chip was fabricated and probably designed by ICS ("Integrated Circuit Systems", Valley Forge, PA, USA) on behalf of Gravis. But okay, maybe they were just a second source. I did find a guy involved in ICS's chip design who I had once contacted, he surely knew something about it or knew the people involved. Coincidentally the company's original location is not too far from me.

See here: http://witt-family.com/jeff-sr/Resume.htm

I still plan on contacting him again to see what else if anything he or his friends/former coworkers have squirreled away. I last touched base with Jeff in 2014: Re: ASC Media Master synthesizer

Still, the ICS datasheet PDF's that I've collected so far are generally all "second source" Ensoniq chips, nothing Gravis specific.

Anyhow, the ICS1614 (which also seems to be labeled the ICS11614?) is allegedly an ASIC based on the Ensoniq DOC-II, aka the ICS1399.

ICS1399:
https://datasheet.datasheetarchive.com/origin … AIH00051221.pdf
but it seems a little older and smaller.

The Gravis GF1's successor, the "GFA1", became the AMD InterWave (Am78c201) and datasheets and even SDK for that are definitely around if you know where to look.

MAME even has a WIP emulation of the Gravis Ultrasound of its own, unrelated to the GusEmu code that DOSBox found its way to back in the day:
https://github.com/mamedev/mame/blob/master/s … bus/isa/gus.cpp
https://github.com/mamedev/mame/blob/master/s … s/bus/isa/gus.h
licensed BSD-3-Clause and credited to mahlemiut (Barry Rodewald).
Unfortunately it does not also document the pinouts of the Gravis GF1.

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But now let's look closer at an ICS chip called "WaveFront".

The ICS ICS2115 "WaveFront" chip, a 32-voice wavetable synthesizer used in Turtle Beach Maui sound card and other Turtle Beach products, used the same 84-pin PLCC package as the ICS1614.
https://csclub.uwaterloo.ca/~pbarfuss/WaveFront_ics2115.pdf

(MAME also has an ICS2115 emulation: https://github.com/mamedev/mame/blob/master/s … und/ics2115.cpp / https://github.com/mamedev/mame/blob/master/s … sound/ics2115.h )

The ICS2115 also can use an ICS2116 system interface chip which is a 100-pin PQFP, similar to the Gravis Ultrasound "Advanced Gravis GF1D1".
https://datasheet.datasheetarchive.com/origin … A2IH0067320.pdf

PERHAPS the ICS2115 is the same or similar pinouts as the GF1 / ICS1614 / ICS11614. And PERHAPS the ICS2116 has the same/similar pinouts to the GF1D1.

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I'd need someone capable of tracing out some of the original Ultrasound board to be able to say more. So for now, for me, this question is unanswered. But it seems possible!

Note that I am not saying that GF1 / ICS1614 / ICS11614 *IS* the Wavefront ICS2115.

But they seem to share packages and perhaps pinouts as well. There's definitely "a family resemblance"! 😉

[EDIT] They do not share pinouts. Thanks, Tiido.