Nice.
By the way, have you tried the keyboard beeper?
Search found 337 matches
- Mon Mar 19, 2018 3:15 pm
- Forum: Hardware
- Topic: Keyboard beeper
- Replies: 3
- Views: 1811
- Mon Mar 19, 2018 3:09 pm
- Forum: Development
- Topic: ZX81 ULA-in-a-CPLD
- Replies: 238
- Views: 123546
Re: ZX81 ULA-in-a-CPLD
I all Zeddys that I've got the NEC Z80 clone is sitting. The uPD780C datasheet is referring to:
- Address lines 50pF
- Data lines 200pF
- Sun Mar 18, 2018 1:03 pm
- Forum: Development
- Topic: ZX81 ULA-in-a-CPLD
- Replies: 238
- Views: 123546
Re: ZX81 ULA-in-a-CPLD
It seems that I am back on the track. The ULA is alive, works in FAST mode only, loads some BASIC software, reads keyboard, execute BASIC command. Furthermore I ran a BASIC benchmark and its execution time was the same like my other Zeddy in the FAST mode. Regarding "SLOW" mode, see the screen shoot...
- Sun Mar 18, 2018 12:43 pm
- Forum: Development
- Topic: Bad Apple UDG
- Replies: 23
- Views: 10913
Re: Bad Apple UDG
My jaws dropped to the floor and can't lift them up.
- Sat Mar 17, 2018 12:24 am
- Forum: Development
- Topic: ZX81 ULA-in-a-CPLD
- Replies: 238
- Views: 123546
Re: ZX81 ULA-in-a-CPLD
I am back to square one. No proper keyboard reads, my Zeddy boots to the "K" prompt in the FAST mode only, a lot of noise on the ground plane of the Zeddy PCB and the noise is visible in the video signal too.
- Thu Mar 15, 2018 1:55 pm
- Forum: Development
- Topic: Tzxduino
- Replies: 3
- Views: 3033
Re: Tzxduino
Hi Bill, I use one, precisely it is the Zaxon's variant of TZXDuino ( SMR ). It works well with any .p and .o files for ZX80/ZX81. These formats have been supported by the TZXDuino firmware for a while since its rev. 1.3 was released in May 2017. The current F/W is in rev. 1.81 or so. I can post som...
- Wed Mar 14, 2018 7:24 pm
- Forum: Development
- Topic: ZX81 ULA-in-a-CPLD
- Replies: 238
- Views: 123546
Re: ZX81 ULA-in-a-CPLD
Yes. See below
- Tue Mar 13, 2018 11:17 pm
- Forum: Development
- Topic: do we still use UHF modulators ?
- Replies: 17
- Views: 7955
Re: do we still use UHF modulators ?
Thanks Andy. I did more searching in a few places including forgotten folders on my hard drive and I've found it.
- Tue Mar 13, 2018 10:46 pm
- Forum: Development
- Topic: do we still use UHF modulators ?
- Replies: 17
- Views: 7955
Re: do we still use UHF modulators ?
Has anyone got any schematic diagram or datasheet of the UM1233 modulator? I would appreciate if you could share it, please.
- Tue Mar 13, 2018 10:05 pm
- Forum: Development
- Topic: do we still use UHF modulators ?
- Replies: 17
- Views: 7955
Re: do we still use UHF modulators ?
Paul,
In my case the cost is a secondary issue, because we are talking about difference in voltage levels at the pin 16 of the ULA only. The development time could be longer but I think, both variants are feasible.
In my case the cost is a secondary issue, because we are talking about difference in voltage levels at the pin 16 of the ULA only. The development time could be longer but I think, both variants are feasible.