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RE: [N8VEM-S100:1455] S-100 board reorders

Hi Andrew,

I'm well underway with my 8080 CPU board project.  It will be a replacement board for the IMSAI 8080 at the Brantford PC Museum.


Their IMSAI 8080 is currently non-operational.  It's missing the 8080 CPU card and was upgraded to a Z80 board.  The problem with the Z80 board, is that it doesn't allow the use of the front panel.

The 8080A CPU card I'm building here will be a full SBC with RAM, Console I/O and an emulated disk system.  The RAM is going to be a single 32K RAM chip (62256) or two chips stacked for 64K.  The Serial I/O is going to be through a PIC chip configured as a slow I/O chip (wait states added to communicate).  The same PIC chip will interface to a 4M Flash chip (not shown in picture) to emulate a disk system that can be loaded with CP/M.  As a bonus, I'm going to try to use the same PIC chip to load a boot strap program into RAM.  This will cut out an EPROM chip and extra wiring.

Right now, I have the CPU running, RAM operational.  Working on PIC chip firmware to get I/O, Disk & Boot.

I can post schematics later, once I verify circuit operation.

PS.  This CPU card has the 16 pin connector (local data bus) used by the IMSAI 8080 front panel.


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