View the Guestbook
I reserve the right to delete double or offending entries. I might comment some entries, so beware!
In the former East Germany many people built a ZX-clone themselves.
I also was a part of this great idea, to construct a 100 % code-compatible
clone, using available chips of the Z80-family (Z80 named U880 in East
Germany) The PIO, and some TTL-chips were used to simulate the ULA. We used
a 4 MHz-Z80 and DMA-request to read out the memory. So was the real clock
rate near 3 MHz. A problem was the tape loading. We switched off the
DMA-Request from graphik hardware to meet the real time requirements in the
loading procedure. It worked fine. The only problem was, that we could not
see the title picture prior the game. We used 64 MB RAM and did copy the 16
KBYTE ROM into the RAM on the Boot-time. So the chipselect-logic was very
simple. Hardware was not greater then a normal PC-keyboard. We did pack the
board (2-layer-Board) together with the keybord in a box.
It was a non comercial project. In the former East Germany, were any of such
privat projects. Every student had his own ideas to make a 100 % compatible
The best was a debugger. It was started with a NMI-key (NMI of the Z80). So
we could debug every game or application.
Feel free to contace me, if you want to have any photos of my clone.
Any chance of porting this to OS X?
I don't have access to OS X. Volunteurs are welcome!
I wanted to find any picture of my first computer in life. That was Zx
Spectrum 48kb. In my countrie then was huge rivalry against Comodore 64kb. I
saved an picture from this site (ZX spec. with Jet pack game, horizons...).
Great Basic programing, great games... for that times.
Old, good times...
Branko (Krusevac, Serbia)