During the 1980's my job involved embedded control using the Motorola 6800 and 6809 series microprocessors so when I managed to buy two 8" disk drives at an affordable ( just ) price I was able to design and build my own 6809 based system.
This has lain untouched for about 25 years until prompted by a post on this forum I dug it out and intend to get it going again.
Its not exactly small or light!, case is 3mm aluminum sheet, the card frame on the left takes up to 6 U4 cards on a custom bus, the 2 drives are on the right and the PSU ( linear ) at the rear, 5,12 -12 and 24V for the drives.
The cards are as follows
Left front, the CPU with 6809 , 64k Dram, monitor and boot EPROM, RS232 for console and parallel ip for keyboard. Dram was cheaper and smaller than static and its fairly easy to use with a 6809.
Middle card, more I/O, 4 x 8 bit ports and a handful of handshake / strobe curtesy of a 6821 PIA and a 6522 VIA, 2 more RS232 ports and a real time clock, the NiCad of which is responsible for the blue corrosion all over centre of the board Grrr.
Front right, display card, HD6845 based with added BBC mode 7 using a SAA5050.
This in fact was the mark 2 card, the mark 1 being a straight TTL,RAM, EPROM, 32 line x 64 char card.
Top Left, Disk interface using MB 8877, I think that's a Fujitsu part, I think Im running MFM but will have to check as it is a long time ago.
Top Right, not a wire wrap card, but also not a commercial but a 6800 card from my work, my design though, only used here for power up reset as I couldn't be bothered to put this on the CPU card !,
The OS was the TSC FLEX 09 OS
Progress so far, PSU run up and test with cards out, ok, cpu and display cards in , nothing !!. I have found my original design notes and drawings so there's some serious trouble shooting coming.
DaveH
This has lain untouched for about 25 years until prompted by a post on this forum I dug it out and intend to get it going again.
Its not exactly small or light!, case is 3mm aluminum sheet, the card frame on the left takes up to 6 U4 cards on a custom bus, the 2 drives are on the right and the PSU ( linear ) at the rear, 5,12 -12 and 24V for the drives.
The cards are as follows
Left front, the CPU with 6809 , 64k Dram, monitor and boot EPROM, RS232 for console and parallel ip for keyboard. Dram was cheaper and smaller than static and its fairly easy to use with a 6809.
Middle card, more I/O, 4 x 8 bit ports and a handful of handshake / strobe curtesy of a 6821 PIA and a 6522 VIA, 2 more RS232 ports and a real time clock, the NiCad of which is responsible for the blue corrosion all over centre of the board Grrr.
Front right, display card, HD6845 based with added BBC mode 7 using a SAA5050.
This in fact was the mark 2 card, the mark 1 being a straight TTL,RAM, EPROM, 32 line x 64 char card.
Top Left, Disk interface using MB 8877, I think that's a Fujitsu part, I think Im running MFM but will have to check as it is a long time ago.
Top Right, not a wire wrap card, but also not a commercial but a 6800 card from my work, my design though, only used here for power up reset as I couldn't be bothered to put this on the CPU card !,
The OS was the TSC FLEX 09 OS
Progress so far, PSU run up and test with cards out, ok, cpu and display cards in , nothing !!. I have found my original design notes and drawings so there's some serious trouble shooting coming.
DaveH