Sinclair ZX80 / ZX81 / Z88 Forums

Hi, the source (for use with TASM) had not been published because of its quick-and-dirty style. Anyway. Please find it attached for your disposal.
Greetings, Oliver

Hi Andy, The Zeddy-board has 14 Chips + RAM+ROM+CPU. Schematics can be found here: http://forum.tlienhard.com/phpBB3/viewtopic.php?f=2&t=331#p1647 (sorry, mostly in German, but you will find the ZX81_Clone_Schem.zip file with the schematics). I already know that the HSync-Timing differs, making the ...

Aaaargh. Seems my homebrew Zeddy made from standard-logic-chips manages to emulate the emulators in real hardware: With_zxtest_lo.jpg The challenge was to build a ZX81-compatible with as few standard-ICs as possible. I knew I omitted some shifters in the sync-Logic, but why..? It will take me a whil...

Here is the tool that should auto-detect ZX81 and ZX80 files (.p/.o/.80 etc) and convert to a sound file:

AFAIK, both file formats consist of the raw byte stream as written on tape. So the differences should be the same as for the tape format: - ZX81 files start with the file name, ZX80 files do not have a name included and just start with the data - The memory offset for ZX81 files is 4009 hex, whereas...

Hi Lee, concerning the HC versus LS logic keyboard problem: Did you look at the pullup-resistors R13-R17? At 47K Ohm, they might probably cause trouble, depending on the stray capacity of the keyboard line: These 47K-pullups need to rise the input voltage above the logic threshold within one I/O rea...

Greetings, I would like to add some details concerning the modification we made to Jens' ZX80-LEGACY last weekend. Firstly, the design and the quality of Lee's ZX80-LEGACY board is really phantastic! After replacing a broken 74LS74 (it just did not provide the divided 3.25MHz CPU clock), the compute...