12 Jul
2010
12 Jul
'10
2:02 p.m.
Andrew Lynch wrote:
Hi! Just out of curiosity does anyone know of any home
brew ISA bus 68K
boards?
Not ISA bus, but I built a homebrew 68020/68881 board for the Apple II
back in 1986. It had an EPROM with boot code, and 32K of SRAM. It used
two eight-bit parallel ports in each direction to communicate with the
Apple, and allowed either processor to interrupt the other. Richard
Ottosen helped me build and debug it, and Loren Blaney developed a
version of the XPL0 compiler to produce native code for it.
I no longer have the card, though I do still have the schematic so I
occasionally get tempted to build S/N 2. Originally I wanted to design
an upgraded version that could DMA into the Apple memory, for higher
performance graphics.
Eric