Sunday, 28 June 2009

Backplane mk.I built

Here's a rather blurry picture of my first cut backplane. The system bus is fed along the IDC cables each card mates using a 64 way eurocard connector.

The board plugged in is the memory board which I built in 2007. I've still not tested the board yet other than to check that the supplies go to the correct pins on each chip!

The memory board has only 32k RAM fitted but the design allows for 48k RAM. The empty IC holder is for the 256k Flash ROM which can be paged into the top 16k of memory space and into the bottom 8k after a hard reset.

Z80 Homebrew Computer


In this blog I will be keeping brief notes of my progress in trying to design and build a Z80 based computer.

I'm in no way holding this up as an example of how things should be done I just hope it will be of interest!

I first started this project back in 2007 and managed to build a RAM/ROM board with boot controller and ROM segment selector (I'll explain in a later post) but then I moved house and have never managed to get round to doing more.

Before I start I'd like to give some thanks to people who have donated many of the components I'll be using:

From uk.comp.vintage back in 2007:
Little Paul - wirewrap sockets
Barry Ruck - ICs and dip switches

From forums (2009):
GMB (George) - Wirewrap sockets
AC/HL (Bill) - Wirewrap gun and bit!
Brianc - Loads of ICs and sockets!

Also many thanks to the people on the vintage-radio forums and the comp.sys.cpm, uk.comp.vintage and comp.sys.acorn.* and bbc-micro mailing list who have given help and advice on programming and electronics over the years.