ESP32 Game Boy Printer (2018) (opens in new tab)

> Ermmm no.

Removing the snide 'Well, akshually...' remark from your comment makes you come across like a much better person.

> Not utilising both cores properly on the ESP32 is a common mistake which causes this (described) behaviour https://randomnerdtutorials.com/esp32-dual-core-arduino-ide/

Doesn't it? :)

Adding to that, it probably shouldn't need to be bit banged. I've found that SPI peripherals can generally be put into a mode that can speak gameboy link cable. When I wrote a gameboy printer emulator in an arduino that simply spoke over serial instead of over wifi, running the emulation state machine as the highest priority task directly in the SPI interrupt worked great.

Other way to do bitbanging without being (as much) dependant on task timing is using DMA engine to just dump the state of pins and parse it after. Same thing with outputting when you need precise timings, no need to burn a core to bitbang if DMA engine is featureful enough.

Yes! This works great, I used it recently. Also notable: there's this custom ROM project for the gameboy camera (requires a custom PCB) https://github.com/HerrZatacke/2bit-pxlr-studio

I also finally finished Pokemon Gen 1 recently, by using one Gameboy and the two original cartridges, in combination with an arduino to trade between them: https://github.com/pepijndevos/arduino-boy

It's a software implementation (on the ESP32 microcontroller) of something that the Gameboy will think is a printer. You print to it, and images are made accessible on the ESP's web server instead of on paper.

I actually did exactly what you suggest a couple years ago.

https://github.com/iamjackg/esp32-phomemo-gameboy-printer

My immediate thought also, I have seen some very cheap thermal printers on Aliexpress and the like that could be used for this purpose.