Icecart-GB

Another ROM Cartridge for the Gameboy. Purpose is to fit the form factor of a gameboy cartridge and act as a ROM cartridge while also providing an arduino-like interface. Emulates the functionality of an official cart, with the different bank controllers implemented in software.

Schematic

It should also have functionality similar to an arduino, where you can interface with it through GPIO and audio in/out. It should be as low-power as possible, since it will run off the gameboy battery. It should support an sd card for storage while powered off.

Requirements:

• STM32-type processor
  • low power
  • Enough pins for cart and GPIO (32+16)
  • rtc
• External mic + speaker 3.8mm jacks
• dac connection to gameboy cartridge audio line for input
• usb C for programming / updating
• 2x8 or 2x6 GPIO
• microsd card slot for storage
• 32Mbit serial ram
• Respond to gameboy cartridge read/write (1MHz ??? Not sure)
  • 4Mihz for gameboy: gekkio notes appendix C
  • 8Mihz for gameboy color?
  • More timing information: https://dhole.github.io/post/gameboy_cartridge_emu_1/
• gameboy dmg/color cartridge footprint
  • https://github.com/Gekkio/gb-hardware/tree/main/GB-BRK-CART
• FreeRTOS

Examples:

• emeryth-hacks: https://emeryth.net/stm32-game-boy-cartridge/
• gekkio: https://github.com/Gekkio/gb-hardware#gb-live32

References:

Old Memory bank controllers TPP1 mapper