FLEXI PLUS 6809 Single Board Computer

(This page is still under construction.)

The FLEXI PLUS 6809 single board computer was a product of The Computerist in Chelmsford MA.

The FLEXI PLUS featured:

• 1 MHz 6809E microprocessor
• seven 28-pin memory sockets for SRAM or EPROM, up to 56KB total
• Fleximon monitor in EPROM
• cassette port (supported several formats)
• one serial port (6551) with RS-232 and 20mA current loop transceivers
• floppy disk controller (1791) for three 5¼" or four 8" drives
• IEEE 488 instrumentation bus (MC68488 controller)
• parallel ports (6522/VIA)
• ??" x ??" PCB (2-layer?, soldermask? silkscreen?)
• FLEX and OS-9 operating systems supported
• cost U$320 for the base system, not including the 6809 ($75), RS-232 ($75), floppy disk controller ($125), or IEEE 488 controller ($125)
• ??-pin user expansion bus (buffered?)

The FLEXI PLUS main board could be expanded with VIDEO PLUS, DRAM PLUS, and PROTO PLUS boards, or it could be used without the 6809E microprocessor as an expansion board for most 6502, 6800, or 6809 systems. Refer to the FLEXI PLUS announcement on page 29 (pdf p.31) and advertisement on page 113 (pdf p.117) of the July 1981 issue of "MICRO - The 6502/6809 Journal".

The FLEXI PLUS was also used as the basis for a complete computer system, the U$3495 Focus. Refer to the full page advertisement on page 36 (pdf p.38) of the December 1981 issue of MICRO. The price had gone up to $3995 in the ad on page 121 (pdf p.125) of the July 1983 issue.

I am in contact with someone who has owned a FLEXI PLUS since the 1980's, and is in the process of restoring it. I hope to post pictures of his system soon. He ran the FLEX operating system on it, but is planning to also port NitrOS-9/6809 Level 1 to it.

"FLEX" was a trademark of Technical System Consultants (TSC).
"OS-9" is a registered trademark of Microware LP.

Last revised 2024-Apr-04 12:43 PDT.
Copyright 2020- David C. Wiens.