The Sinclair ZX80
With its unique place in computing history, there is still a
lot of interest in the ZX80 and, being entirely built from
discrete logic components, with no custom logic chips (other
then the contents of the ROM), it is even possible to build your
has comprehensive details on building your own ZX80, either on
strip-board, or on a recreated PCB, on his
homebuilt hardware page.
Click to open full size image
|Martin Allcorn used this information to build a
ZX80 on a
Eurocard prototyping board, using currently
|A nice feature of Martin's version is that it
has both the ZX80 and ZX81 ROM contents in the ROM
The red jumper block switches between the
two ROMs, and the 4-pin header is for the 5VDC power
|Screen shot from the board running
- with the screen output in reverse video.
The light stripe across the bottom of the screen
is, unfortunately, a "feature" of the design.
|The output levels from the board are such that
normal video is not displayed correctly on a TV
screen - inverse video output is much improved.
The green jumper next to the Z80 CPU switches
between normal and inverse video.
|Running with a copy of the original 4k ROM
|Running with the 8k ROM selected
|Photo showing the system running from the
"external PSU" and connected to Martin's "home brew"
|Keyboard close up
Pictures and other
information courtesy of Martin Allcorn