Galaga uses 4-bit RAMs.  This means that in order to handle 8-bit data, it needs to group RAMs in sets of 2 – one for the lower 4 bits, and the other for the higher 4 bits.  When Galaga detects a RAM error during the self-test, it does not show the location of the failed RAM, they shows which RAM failed. Continue reading Galaga/Bosconian RAM Tip →