MicroKit09 recreation, MicroProfessor-style

The MicroKit09 is a 6809 based single board computer with a 6-digit, 7-segment display, a 34 key keyboard and a cassette interface. It is designed and published as a kit in the French 'LED' magazine in 1983.

The first version of the recreated version is implemented in two boards, like the original:

Yes, the connectors are not properly lined out, I might fix that in a newer version.

The new board has the same components as the original, but another, more compact form factor. The rebuild version has some minor extra's making extension easier:

• Eprom can be enlarged to a 2732 (4kx8)
• RAM can be enlarged to 6264 (8kx8),
• The address space reserved for the 6821 PIA (8kByte!) is split into smaller ranges (1kByte), making room for other perpherials,
• An extension connector is added for a planned MC6850 ACIA board.

Tools used while debugging the boards:

• Logic level probe (a signal level indicator; low, invalid, high),
• Logic signal probe (a CD4040 and LED-array)
,
• MC6809 exersizer. Actually a small Arduino Mega2560 shield and sketch to exersize signals from the processor socket. The sketch is derived from the Z80 exersizer sketch
.

Local links:

• Edited monitor source that works with asm6809
• Keyboard overlay in open office draw format and PDF
• 3D-printed key caps, switch cover and PCB tray
• CPU board schema
• I/O board schema
• Display demo
• Keyboard test
• Still growing quick reference guide for the monitor
• Scanned documentation

The KiCAD and gerber files will be added later.

External links:

• Hackaday page
• Monitor source & image on github
• Thingiverse page
• French forum topic on the MicroKit09
• Documentation and monitor ROM contents
• Grant Sarle's mininimal 6809 system
• Jeff tranter 6809 board. The port of the Assist09 monitor is interesting too. It has Motorola S1/S9 format up- and download.

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Last update: 2023-05-26