When Motorola came out with the MC6809 microprocessor SWTPC came out with a new series of computers. These had a new case to reduce the radio frequency interference that was common among early personal computers.
The new computers came in two versions. The SWTPC 69K which had the MP-B3 mother board that supported 56K of memory. The SWTPC S09 (shown here) had the MP-MB mother that supported a 20-bit address bus for a total of 768K OF RAM.
I had several SWTPC 6800 systems so I just ordered a new 6809 CPU board and modified a old mother board for 20-bit addressing and expanded I/O addressing. I also got 2 extended addressing memory boards so I could have 112K of RAM.
In 2000 I bought a S09 case with just a MP-MB mother board in it. In 2001 I got the SWTPC 6809 documentation in the yellow notebook and a MP-ID board. This gave me a working system because the older serial interface boards could be used. In 2003 I got a MP-S2 serial interface and a MP-L2 parallel interface and now I have a complete S09 System..
MP-ID Photo (231K JPG)
S09 Computer with MP-ID board
CPU Photo (131K JPG)
S09 with 6809 CPU and older serial interface card.
System Photo (148K JPG)
S09 with MP-09 CPU, two 64 k memory boards, MP-S2, DC5 FDC and MP-L2 interface
Rear view of case.
|S09 Case||Bill Dawson|
|MP-ID Board||Sellam Ismail|
|6809 System Notebook||Jon Roath|
|MP-S2 & MP-L2 Schematics||Jeff Hellige|
|MP-S2 & MP-L2 Boards||Bill Sgambati|