MiSTer FPGA Forum

Posted: **Thu May 28, 2020 8:25 pm**

Would love to see an Apple IIgs core

Posted: **Fri May 29, 2020 5:45 am**

I second this..

Posted: **Fri May 29, 2020 6:34 am**

Spunkworks wrote: ↑Thu May 28, 2020 8:25 pm Would love to see an Apple IIgs core

Me too!

Posted: **Fri May 29, 2020 4:49 pm**

It would be amazing! I have tried to contact this author, but I haven't heard anything:

https://www.youtube.com/watch?v=N3AP9sr6C34

Posted: **Fri May 29, 2020 5:41 pm**

Hopefully he will respond as I would love to have a IIgs core.

Posted: **Sun May 31, 2020 12:28 am**

Would love to see this too!!

Posted: **Tue Jun 02, 2020 10:56 pm**

Me too !

Posted: **Wed Jun 03, 2020 2:24 am**

I'd love this, but I'll settle for a finalized Apple //e core

Posted: **Thu Jun 18, 2020 10:48 pm**

I will third (fourth, fifth, sixth, seventh?) this too

The IIGS was a pretty unique computer. It did not have a ton of games (well under 100 IIRC) but it did have some gems. It had a really awesome version of Rastan. Interestingly enough the two other 16-bit computer contenders of the time (Amiga and Atari ST) never got a released port of Rastan. That alone is worth having a IIGS core for in my book!

Posted: **Fri Jun 19, 2020 7:04 am**

For me, the IIgs was the high point in Apple design until the arrival of the iMac.

Now, instead of wishing for an IIgs, how about taking up the mantle to create one yourself.

I have another project started...working from first principles, learning about core development.

If you cannot work on it individually, well then, form a small team to get the core over the line.

Posted: **Mon Aug 17, 2020 4:49 pm**

I'll 10th,11th, 12th and so on for this core to come to fruition. I have a IIgs but more nostalgic for the II Plus and E type keyboard design so might even sell mine when and if a core releases.

Posted: **Tue Oct 20, 2020 9:58 am**

Minimig + ShapeShifter may be so close, isn't it?

Posted: **Tue Oct 20, 2020 12:20 pm**

Isn't ShapeShifter for Mac and not for the IIgs?

Posted: **Wed Oct 21, 2020 6:09 am**

Correct - see this side-by-side comparison from RMA. https://www.youtube.com/watch?v=Jph0gxzL3UI&t=225s

I also recall a thread on Mac on Amiga, but not sure if it was on this, or the old Atari forum.

Posted: **Fri Mar 26, 2021 2:25 pm**

IIGS would be a tough core to do. Not so much for the CPU and graphic modes, as they are pretty straightforward - but for the unique Ensoniq sound chip. Unless it's similar to another sound chip that has been done, it's a lot of work from scratch.

Posted: **Mon Apr 26, 2021 5:21 pm**

There are open source emulators for the IIgs. Wouldn't the source code be helpful in creating a core for the MiSTer?

Posted: **Wed Apr 28, 2021 1:45 am**

rcade wrote: ↑Fri Mar 26, 2021 2:25 pm IIGS would be a tough core to do. Not so much for the CPU and graphic modes, as they are pretty straightforward - but for the unique Ensoniq sound chip. Unless it's similar to another sound chip that has been done, it's a lot of work from scratch.

even a partial IIGS core is more than we have now. IMHO sound can wait get "something" going first to kindle movement.

Posted: **Wed Apr 28, 2021 2:08 am**

I can't locate actual schematics for the ES5503 but there is a lot of information on how it worked and it's exact timings.

Posted: **Wed Apr 28, 2021 2:39 am**

dmckean wrote: ↑Wed Apr 28, 2021 2:08 am I can't locate actual schematics for the ES5503 but there is a lot of information on how it worked and it's exact timings.

I would think for now that building out a IIGS core minus that one component would be of greater benefit then arguing about it absence.

Posted: **Thu Apr 29, 2021 12:34 am**

Here, these might help take care of the sound:
https://github.com/mamedev/mame/blob/ma ... es5503.cpp
http://archive.6502.org/datasheets/enso ... r_chip.pdf

Posted: **Thu Apr 29, 2021 11:30 pm**

Impressive sound chip from 1986!
https://www.youtube.com/watch?v=NEyrydIkBtw

Posted: **Fri Apr 30, 2021 12:10 am**

Maybe I'm missing some subtleties (still an HDL neophyte), but the ES5503 doesn't look all that daunting to me. It's basically an array of 32 almost-identical functional units that seem like pretty straightforward sample playback units. There are some oddities regarding the even and odd members of a pair, and two of the channels not really being usable due to a mask defect or something, but it doesn't seem to be a quagmire of a chip by any means.

Also, I've seen a couple comments suggesting that GS/OS uses the "unusable" channels as timers, so it might not really work to omit it altogether.

Posted: **Fri Apr 30, 2021 12:53 am**

Estrayk wrote: ↑Thu Apr 29, 2021 11:30 pm Impressive sound chip from 1986!
https://www.youtube.com/watch?v=NEyrydIkBtw

If they are PCM like ExCyber says it's not much of a surprise, right?

PS: Greetings from Cranky!

Posted: **Fri Apr 30, 2021 1:36 am**

Just to be clear, I'm not trying to say it wasn't an impressive chip, just that it appears to be much more regular than, say, SID or a Yamaha synth. Basically, it seems like its cleverness had more to do with making 32 channels happen at that price point at that time than it had to do with anything that leaks into the programming model. To put it another way, it "compresses better" as a high-level functional description.

I'm reminded of an interview with Bob Yannes that I read years ago in which he talked about an "oscillator" that was supposed to be shared between all SID channels, but due to a combination of manufacturing process oddities and schedule pressure they ended up basically doing a copy/paste/edit of the silicon layout so that each channel had its own "oscillator" (scare quotes because I'm pretty sure that this term was being used as a metaphor for an analog Moog component, with the actual implementation in the Commodore and Ensoniq chips being based on digital counters). I'd bet that the ES5503 actually achieved some of the particular efficiencies that he'd hoped to implement in SID.

Posted: **Fri Apr 30, 2021 4:58 pm**

ExCyber wrote: ↑Fri Apr 30, 2021 1:36 am Just to be clear, I'm not trying to say it wasn't an impressive chip, just that it appears to be much more regular than, say, SID or a Yamaha synth. Basically, it seems like its cleverness had more to do with making 32 channels happen at that price point at that time than it had to do with anything that leaks into the programming model. To put it another way, it "compresses better" as a high-level functional description.

I'm reminded of an interview with Bob Yannes that I read years ago in which he talked about an "oscillator" that was supposed to be shared between all SID channels, but due to a combination of manufacturing process oddities and schedule pressure they ended up basically doing a copy/paste/edit of the silicon layout so that each channel had its own "oscillator" (scare quotes because I'm pretty sure that this term was being used as a metaphor for an analog Moog component, with the actual implementation in the Commodore and Ensoniq chips being based on digital counters). I'd bet that the ES5503 actually achieved some of the particular efficiencies that he'd hoped to implement in SID.

Yes, supposedly the SID was to be 32 channels also using some tricks that were later used in the 5503 instead.

Posted: **Fri May 07, 2021 9:02 pm**

pgimeno wrote: ↑Fri Apr 30, 2021 12:53 am
Estrayk wrote: ↑Thu Apr 29, 2021 11:30 pm Impressive sound chip from 1986!
https://www.youtube.com/watch?v=NEyrydIkBtw
If they are PCM like ExCyber says it's not much of a surprise, right?

PS: Greetings from Cranky!

Cranky! hey my friend! we haven't seen each other for a long time! still at Valencia?

Yep, anyway sounds like the angels:
https://www.youtube.com/watch?v=wxzH5kdejAA

Posted: **Fri May 21, 2021 9:20 pm**

Not sure if this is helpful, but here is a schematic: https://www.applefritter.com/files/2021 ... ematic.pdf

Posted: **Fri Oct 01, 2021 12:55 pm**

The hard drive support on Apple2 has piqued my interest in this - did anything come of the ideas etc?

Another great demo here https://youtu.be/73X9O2dQ0rM?t=37 showing OXYGEN running with some lovely sound.

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