Show HN: Game Bub – open-source FPGA retro emulation handheld

Populated PCB in quantity 100 would probably be 60-70 USD, yeah. Maybe a bit less, it really depends on how much you can buy the FPGAs for.

I really did want to switch to the RP2350B, but it's (still) not available to buy. There's also the (unreleased) Raspberry Pi RM2 module which would help with Bluetooth Classic and LE support.

On Game Bub, I do expose a Pmod interface (4 data wires) connected to the FPGA, so that actually is an option here too.

I think latency is the one aspect where FPGA systems can be genuinely better because you don't have to have mountains of abstractions and frame-buffering between the controller and the display, the controller can poke values directly into memory and the graphics core can "race the beam" much like the original hardware did. Besides that the benefits are pretty tenuous though, yeah.

I agree, and wrote a rant about this as part of the post: https://eli.lipsitz.net/posts/introducing-gamebub/#a-brief-r...

IMO: the only real advantage is that it allows you to meet the precise timing needed to interface with physical hardware, like cartridges and other consoles (with link cables).

I think they're also really fun to write, because you think more like a hardware designer than a software engineer.

Consider that you can emulate an FPGA on a CPU, just much slower.

Thanks! Slint has been great to work with :)

We do, sort of. There are ASIC based clones of the NES, SNES, Genesis, GBA and GBC. Hyperkin for example sells a few, the SupaRetron HD is an ASIC based SNES clone, the MegaRetron HD is an ASIC based Genesis clone. Some Chinese companies have Game Boy Clones (e.g., GB Boy Colour). They aren't perfect because they aren't perfect 1:1 reverse engineered chips and nobody seems willing to spend the money to fix all the bugs, but they can be pretty close. The main benefit of the FPGA systems is that bugs can be fixed and they can do more than the real systems if need be like scan line emulation.

It's been done before. Lots of 90s bootleg consoles used clones of the Famicom/NES chips, though they weren't particularly accurate clones. The Commodore 64 Direct-To-TV of all things had a custom ASIC made for it in 2004.

I think these days FPGAs have just gotten cheap enough that the economics of making custom chips doesn't make much sense for the volumes these kinds of products tend to sell.

I imagine there's a huge difference, legally, with black-box reverse engineering and then creating a very similar design on an FPGA (what I did here), and actually fully decapping the chip and cloning the gates.

Plus FPGAs add a lot of flexibility (e.g. multiple systems, enhancements), and they're really not that expensive. Especially in relatively low volumes compared to an ASIC.

There's a Gameboy clone made by kongfeng that seems kind of like this, with its own chip. I'd love to know more about how they created it.

I believe NES patents might be finally all expired and off this year, but the SNES is probably covered for a little longer. Reverse engineering emulators and fpgas has been safer legally speaking for most of the last few decades.

Yep, that’s definitely a concern with hardware projects. I guess mass produced hardware doesn’t run into the problem as much because there’s funding for upfront bulk component purchases.

At least with open source hardware you could theoretically modify the hardware to use an alternative component, even if it’s no longer commercially viable.

For a lot of open source projects you can pretty much just source everything from DigiKey or Mouser, so you can buy them all atomically.

You're literally describing a product and a company that already exists (Analogue Super Nt: https://en.wikipedia.org/wiki/Super_Nt)

This is an open source analogue pocket.

This main distinguishing feature of this project is that it supports physical cartridges, whereas MiSTer and almost every other emulation handheld doesn’t.

The FPGA cores here are written from scratch by me with hardware support in mind, and it’s quite a bit of work! Plus, SNES cartridges don’t exactly fit in a handheld :)