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

Yes, the connectors are not properly lined out, the version 1.1 fixes that.

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 more options, like RAM or the MC6850 ACIA / 6840 PTM board.

Tools used while debugging the boards and software development:

• 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.
• ROM emulator

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.

email

Last update: 2023-06-09