Search found 6 matches

by Oliver
Thu Aug 25, 2011 11:28 pm
Forum: Sinclair Misc
Topic: does your zeddy (or emulator) work like the real thing ?
Replies: 17
Views: 6851

Re: does your zeddy (or emulator) work like the real thing ?

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 ...
by Oliver
Thu Aug 25, 2011 10:16 pm
Forum: Sinclair Misc
Topic: does your zeddy (or emulator) work like the real thing ?
Replies: 17
Views: 6851

Re: does your zeddy (or emulator) work like the real thing ?

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...
by Oliver
Thu Feb 24, 2011 10:57 pm
Forum: Development
Topic: ZX80 convert .o to .wav
Replies: 18
Views: 10959

Re: ZX80 convert .o to .wav

Here is the tool that should auto-detect ZX81 and ZX80 files (.p/.o/.80 etc) and convert to a sound file:
zx_p2wav_v0_04.zip
File converter with C language sources
(18.58 KiB) Downloaded 351 times
by Oliver
Tue Jan 11, 2011 8:47 pm
Forum: Development
Topic: 80 file format, 81 file format
Replies: 3
Views: 10805

Re: 80 file format, 81 file format

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...
by Oliver
Mon Nov 08, 2010 9:00 pm
Forum: Development
Topic: New ZX80 boards
Replies: 194
Views: 106576

Re: New ZX80 boards

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...
by Oliver
Tue Jul 27, 2010 11:52 pm
Forum: Development
Topic: New ZX80 boards
Replies: 194
Views: 106576

Re: New ZX80 boards

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...