28 pin Atmel AT 29C256 flash programmer cartridge for Commodore 64.
There is a BUG in this circuit, which may cause it not to work. The problem maybe is that the address is basicly not valid at the rising edge of PHI2 clock coming from the C64. This is described in this web page by A. Fachat.
Following postscripts packed into c64fpps.zip :
Top overlay of pcb
Top layer of pcb
Bottom layer of pcb
Schematic diagram in a scanned GIF.
c64ftest.asm Test "demo" program, that doesn't have a user interface. It can be assembled with DASM. This and many other programming tools can be found at ftp.funet.fi