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Open Source Sega Hardware If Retro Engine can, why can't Open Source?

#16 User is offline biggestsonicfan 

Posted 03 November 2018 - 01:02 PM

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View PostBlack Squirrel, on 02 November 2018 - 01:56 PM, said:

Usually these sorts of hardware projects gain traction when there's a genuine need for them to exist. There are people making replacement sound card devices for IBM PCs because the price of real ones second hand is extortionate. With the original NES, the 10NES chip can stop a system from working, and picture quality is poor - you might not want to deal with that noise in 2018.


However with a Mega Drive, there are millions out there that still work fine. Emulation is above average and Sega has most of its best games readily available on almost everything produced this century - your dream will come true eventually, but in the here and now, the problems aren't big enough to deal with.


Posted Image

You are technically correct, which is the best kind of correct. I put "if Sonic Mania can do it" as a sub-tag merely because without Sonic Mania, would we really have a point of reference to judge things like Sonic Forces or other attempts Sega has made at 'classic' Sonic if the collective efforts and knowledge of what was essentially the community shared info to establish a solid enough foundation for what 'classic' really is?

I know it's not going to happen any time soon, but that doesn't mean I can't be the mad scientist and post my research notes first so others may benefit down the line. We're literally starting the foundation in this thread mind you. Well, my foundation anyway. Anyone and everyone is welcome to build from their own ground up mind you.

#17 User is offline biggestsonicfan 

Posted 25 December 2018 - 07:43 PM

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So for Christmas my mom revealed that Pengo was her favorite arcade games and now I want to do the Pengo FPGA....

#18 User is offline Aerosol 

Posted 28 December 2018 - 01:16 PM

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Things like this are what initially drew me towards electrical engineering as an area of study.

#19 User is offline Sonikku2k 

Posted 17 January 2019 - 07:29 AM

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View PostTurbohog, on 26 October 2018 - 10:40 PM, said:


Thanks for the link. I've been hearing about this project a bit lately and hadn't looked into it at all.

So basically, a field programmable gate array (FPGA) can be thought of as a re-programmable silicon chip. FPGAs are used in commercial products and are also sometimes used for both prototyping ASICs (since they are reconfigurable). Normally, you create circuit designs for an FPGA by writing in a hardware description language (HDL) such as Verilog or VHDL. HDLs are very different beasts from programming languages as you are describing hardware that runs in parallel and not sequential code, which is how you normally think when writing software. After your HDL is written, you use tools, normally provided by FPGA vendors, to physically map the design to hardware. Depending on the complexity of the design, this can take anywhere from a few minutes to a week. Cores are often distributed that contain implemented FPGA circuits; sometimes these are open and you can see and edit the HDL. Sometimes the cores are distributed in other ways where you can't see the source. It can be pretty difficult to do write HDL, etc. which is probably why FPGA-based emulators and things aren't more common right now.

The advantage of using FPGAs is of course that if you have the proper knowledge of a some piece of Sega hardware, you could replicate it nearly exactly on an FPGA. So if you knew exactly how the processor used in the Sega Genesis worked, you could basically create an identical implementation of it on an FPGA. Same goes with any other Sega HW. You could then in theory add functionality to the hardware as well.

It looks like the MisterFPGA project is using a board with an Intel SoC that contains an FPGA coupled to a hard ARM processor (as opposed to a soft processor implemented in an FPGA). I don't know the details, but they are doing some sort of hybrid-approach to emulation - some things are emulated by software (with the ARM processor) and some things are emulated by the FPGA. Specifically looking at the Genesis portion of the project, they have cores for the main CPU (TG68K), the sound CPU (Z80), the Sega PSG sound chip, and whatever the JT12 is.

While the TinyNES looks cool, I honestly think FPGAs are a better long-term option as you aren't necessarily dependent on having original hardware like the TinyNes project uses.


FPGA technology is always going to be a winner. Especially since I've seen and experienced quite a few well-known brands who showed me their work-in-progress of a new product being implemented in an FPGA as a proof-of-concept.

FPGAs are always my go-to for when I have to marry ancient systems to new ones.

Reproducing old SEGA chips at the silicon level is going to be prohibitively expensive.. because technology moves on. The process used in those days, is likely very costly now. Every year the semiconductor industry chases the goal of smaller feature sizes and processes to get costs down and yields high. This is why an FPGA makes even more sense. If the FPGA is obsolete, no problem, recompile the HDL source for the new FPGA (after adjusting the constraints file to account for the differences incurred in silicon) and BOOM, back in business.

BUT, getting everything beautifully cloned is always a challenge. I would love to know if companies like SEGA hang onto hardware IP of yesteryear or if it becomes destroyed during the dissolution of various business units i.e. when they stopped making hardware, did they lay off all those people and then just bin all the source code, hardware files, etc? Because if by some miracle, you could obtain that, it would make an IP core of the original hardware quite easy to develop. I suspect they hang onto it, but will charge you an absolute fortune + licensing fees if you even were successful in requesting a license to reproduce it. An example that comes to mind is that HOLLY chip in the Dreamcast. I see lots of surplus stock of that chip on Chinese websites (I suspect 8 out of 10 ads are fake), but yeah, reproducing that functionality accurately in an FPGA as a soft core, would be amazing.

#20 User is offline biggestsonicfan 

Posted 21 January 2019 - 10:10 AM

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View PostSonikku2k, on 17 January 2019 - 07:29 AM, said:

FPGA technology is always going to be a winner.

I completely disagree. The design of the original Sega hardware, especially for systems not fully reverse engineered such as the 32X and select arcade boards, namely Model2 onwards and including things like the Triforce and Lindbergh, will not be possible to create 1:1 hardware setups within the FPGAs. It's not a question of redesigning the wheel, but using components from older, dead hardware, and recycling that into new boards like the Mega Blaster does in the original post. In some cases, we may never have a blueprint of the silicon layout to reproduce into an FPGA. The homebrew hardware scene is very niche, yes, and does require quite a bit of time to source components, but can produce very high-quality results.

There is also the factor of what interference should be caused by component layouts in the original design as well as any flaws that exist. As far as I understand, FPGAs mitigate these design flaws.

#21 User is offline Sonikku2k 

Posted 31 January 2019 - 01:26 AM

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View Postbiggestsonicfan, on 21 January 2019 - 10:10 AM, said:

View PostSonikku2k, on 17 January 2019 - 07:29 AM, said:

FPGA technology is always going to be a winner.

I completely disagree. The design of the original Sega hardware, especially for systems not fully reverse engineered such as the 32X and select arcade boards, namely Model2 onwards and including things like the Triforce and Lindbergh, will not be possible to create 1:1 hardware setups within the FPGAs. It's not a question of redesigning the wheel, but using components from older, dead hardware, and recycling that into new boards like the Mega Blaster does in the original post. In some cases, we may never have a blueprint of the silicon layout to reproduce into an FPGA. The homebrew hardware scene is very niche, yes, and does require quite a bit of time to source components, but can produce very high-quality results.

There is also the factor of what interference should be caused by component layouts in the original design as well as any flaws that exist. As far as I understand, FPGAs mitigate these design flaws.

Of course it will never be possible to create a 1:1 setup. What I meant was, for creating an emulated platform, an FPGA is an obvious choice.

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