The Game Raccoon Revision 1 is a cartridge for the Sega Mega Drive which allows software developers to boot game images stored on SD card on Mega Drive hardware. An internal menu allows the user to select an image to be written to the internal memory, which can then be played as if it were running from a Mask ROM cartridge.
Bus arbitration and SD card IO is performed by a PIC24 microcontroller. An 8 megabyte Flash module provides reprogrammable independent boot menu and game testing partitions. The cartridge uses correct level-shifting on all interfaces.
PCB designed in EAGLE. PIC24 firmware written in C, boot menu M68000 code written in assembly and compiled with Bruce Tomlin's asmx. All available under copyleft licenses.