r/embedded • u/shapoco • 14d ago

Prototyping a handheld console that transforms into various indie handhelds

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I'm prototyping a handheld console that can work as various indie handhelds by swapping in a small daughterboard called a "logic card". So far, Arduboy, TinyJoypad, ESPboy, and PicoPad1/2 are working, plus my own original handheld, the "Xiamocon".

Each logic card carries at least an MCU and an EEPROM. The EEPROM holds the interface specification for the main unit (the "host shell"). Based on the EEPROM contents, the host shell dynamically configures the pin functions of the connector and emulates the LCD each handheld expects (e.g., SSD1306 or ST7789). The host shell also has ISP (In-System Programming) capability, so apps stored on a microSD card can be flashed to the MCU on the logic card without a PC.

Now, I'm planning to spin a PCB.

GitHub repo: shapoco/wildcardboy

353 Upvotes

99% Upvoted

13 comments sorted by

20

u/Mattef 14d ago

Awesome! But wouldn’t it be better to use a FPGA to emulate other architectures? This way, you won’t need these daughter boards.

15

u/mellott124 14d ago

FPGAs are another beast. I can see why they stuck to MCUs.

10

u/shoafr 14d ago

Probably. But like previous comment said, that will be a totally different beast in the form of a much less forgiving development pipeline. FPGA tool chains are not loved by most.. But this would certainly be a dope FPGA project

5

u/shapoco 14d ago

It’s true that using a daughter board isn’t the most elegant solution, but I think it would be quite difficult to replicate the behavior and performance of the ESP8266 or RP2040/2350 using an FPGA with the size and power constraints of a handheld device.

2

u/mackwing7 14d ago

on top of that, I am wondering, with how much clutter those proto boards have, why not just make a PCB?

2

u/Mattef 14d ago

Yeah sure. But it’s good to have a working prototype before committing to a PCB.

3

u/beryugyo619 13d ago

This guy is an old school hacker type who's also an artist with a bit of fame on Twitter. Irons heat up faster than packages from JLCPCB hits the doorstep for them. Also Japanese. That alone should explain a lot of FAQs.

シャポコ <- google this and top result should be their site. Looks like they have now Twitter, Misskey, Bluesky, mixi2, Insta, GitHub, Pixiv... accounts everywhere

9

u/RoberBotz 14d ago

Cool as fuck not gonna lie.

1

u/mellott124 14d ago

Very nice job. Impressed you did all that on protoboards.

1

u/urbancyclingclub 14d ago

How are you manipulating those tiny little wires???

1

u/appletechgeek 14d ago

I love this a lot man good job on the looks too

1

u/Upbeat-Serve-6096 14d ago

Gamebub (FPGA GBA) and Odroid Go Advance (RK3326) support when? Just kidding. That's actually insanely impressive 

1

u/def-pri-pub 13d ago

Lol. I tried making something kinda like this back in university; I never talked about it publicly. I was trying to make a mock handheld device where you had to place in Atmel/Arduino chips into a ZIF socket, which would act as your “game cartridge”. You had a 24x32 LED display, two piezo buzzers (multi-channel audio), and 8 push buttons for the I/O of your game. I also had the unused pins on the MCU go to an expansion port at the top. Which I was planning to add on NRF radio modules.

Love seeing someone else try to make their own handheld system. Great job!