Creating new Sega Game Gear ASIC from FPGA core?

Discussion of developmental aspects of the MiSTer Project.
seastalker
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Creating new Sega Game Gear ASIC from FPGA core?

Unread post by seastalker »

I have been fixated for a while on this video about a 'NEW' Sega Game Gear in 2021 by Macho Nacho:
https://www.youtube.com/watch?v=tgnbuYgp_oI

For brevity sake, a summary: Mathijs Nilwik has completely reverse engineered the Sega Game Gear, creating custom new motherboard and both daughter-boards, with improvements (1 chip ASIC version). The only things you provide are the original ASIC chip, cartridge reader, and EXT port.

Though I can see an aftermarket cart reader and Ext port feasible, the market for them and possibly even Mathijs's whole mainboard project is perhaps hindered by this ASIC requirement. I get it if the ASIC is the Game Gear system-on-a-chip that makes a Game Gear a TRUE Game Gear. Still, the need to desolder and then resolder with fine pitch finesse is a huge hurdle to overcome, especially given that I have not seen many reputable install services offer this (none yet actually that I've seen).

THE BIG IDEA: Could the MiSTer Sega Game Gear core be made into a new cost-efficient chip that could be used as a replacement for the ASIC? I've thought about CPLD vs FPGA options too. If a new Sega Game Gear is available down to even new cases, buttons and screens, I think this ASIC hurdle is the last major aspect to bring the Game Gear to larger audiences.

If the better goal is to use some FPGA chip for this (cost?), would other cores work well with a D-PAD, start button and two action buttons? Some NES or arcade? Do SG-1000 games work with a MasterGear Everdrive

I see this project with major potential to be a better Game Gear given new technology not available to Sega at the time. I love Mathijs Nilwik's idea and work to give new life to a dead Game Gear motherboard. I can ALSO see it only get better with more options like some ASIC replacement to give more functionality, ALL brand new parts, and ease of install.
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Re: Creating new Sega Game Gear ASIC from FPGA core?

Unread post by Reed_Solomon »

Those old Nes on a Chip clones are ASICS made out of an old FPGA NES design. Nobody has ever bothered to update it because it's quite expensive to produce an ASIC so you would have to expect a decent return on your investment to do so. Could it be done? Probably. But for a system that size it might just make sense to use a smaller FPGA and port the core to run on that system. There is nothing to prevent anyone from doing so.
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Re: Creating new Sega Game Gear ASIC from FPGA core?

Unread post by jca »

Coincidence?
I am not too sure of what it is about but someone seems to have taken the FPGA code of SN76489 developped by Jotego and put it on real silicon, not FPGA.

We can take our retro systems to common silicon chips too! Not just FPGA. This is possible thanks to Matthew and the people working on FOSS tools for full silicon design.
Quote Tweet
Matthew Venn
@matthewvenn
· 43m
JT89 FPGA Clone of SN76489 hardware by Jose Tejada @topapate.

https://github.com/jotego/jt89

The SN76489 is a Texas Instruments chip from the 1980s used for sound generation on the BBC Micro, Sega Master System and lots more.

https://en.wikipedia.org/wiki/Texas_Instruments_SN76489


About 170 x 170 um on Sky130.
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Re: Creating new Sega Game Gear ASIC from FPGA core?

Unread post by seastalker »

Yes, as I comprehend it, an over-simplifying explanation is that most (all?) chips originally started life as FPGAs and then were made into non-rewritable chips to make them cost-efficient for mass production. Think of the Atari Pokey IC or the Commodore 64 SID chips for example. Some full systems have been re-implemented onto one-chip designs like the Atari 2600 on a Atari Flashback 2, and a Commodore 64 on the early plug n play "C64 Direct-to-TV".

Of course, I realize I am posting such a crude explanation on a forum of FPGA geniuses who will likely cringe [justifiably] at my explanation. Regardless, the good news I just learned is that RetroSix and Mathijs are already working together:
https://www.youtube.com/watch?v=fNnlTTRwrd4

RetroSix is apparently making a NEW Sega Game Gear cartridge port, and mentions the ONLY thing left that is 'old' is the ASIC. This implies that an EXT port or device functionality replacement is already accounted for? Wouldn't a clean HDMI out solution be nice?

For the most part, it seems the ASIC is the only current setback (re: advanced soldering) for having a 100% brand new Sega Game Gear in 2022.
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Re: Creating new Sega Game Gear ASIC from FPGA core?

Unread post by Newsdee »

seastalker wrote: Fri Jul 01, 2022 11:45 am a Commodore 64 on the early plug n play "C64 Direct-to-TV"
From what I read about it, making the DTV was grueling work and very expensive to produce. And although it sold well, it didnt really meet the expected success.

The way they talk about it, it seems unlikely a new product will go the ASIC route when half-assing an emulator frontend gets you there enough to put products on shelves with much less cost and risk.
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Re: Creating new Sega Game Gear ASIC from FPGA core?

Unread post by jca »

I found a little more information:
https://www.mattvenn.net/stem/zero-to-asic-course/
seastalker wrote: Fri Jul 01, 2022 11:45 am ...
Wouldn't a clean HDMI out solution be nice?
From the link posted above you can reach:
https://www.zerotoasiccourse.com/post/asic_submitted/
which includes
2 mm2hdmi
HDMI driver
author: Aleksandar Pajkanovic
https://github.com/nanoluka/mm2hdmi.git
Sectorseven
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Re: Creating new Sega Game Gear ASIC from FPGA core?

Unread post by Sectorseven »

Would this work as a method for manufacturing new chips?

https://developers.google.com/silicon
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Re: Creating new Sega Game Gear ASIC from FPGA core?

Unread post by seastalker »

It all seems possible, perhaps even likely(?) this will happen some day. In the latest Lu's retro source Mister news update.

FPGAs to ASICs is discussed:
https://www.retrorgb.com/mister-fpga-ne ... -more.html
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Re: Creating new Sega Game Gear ASIC from FPGA core?

Unread post by dmckean »

It's of course possible but the main thing is the economics of it have to make sense. Plus right now is chip fabrication being expensive and at capacity and the existence of FPGA chips that are sub-$10 in volume, it could be a while before we see this happen.
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