Roger -
Great to hear. I take very little credit, it was Geoff who did the design and published all of the necessary files.
BTW I also used a ZRT-80 for many years. Somewhere in one of many moves I lost mine, but would still like to find one again. It was a pick'y design but was affordable. One funny glitch I learned is that it would only work with the Hitachi version of the 6845...
Happy to program PIC's for you, but with a working board it's really easy. Just remove all of the baud rate jumpers and populate the ICSP header. You need a PICKIT3 programmer (there are cheap Chinese knock-off's on Ebay for around $15), the .hex file from Geoff's site and MPLAB IPE (free). I won't tell the Atmel folks...
- Gary
On 10/10/2015 9:21 PM, norwestrzh via N8VEM-S100 wrote:
Great to hear. I take very little credit, it was Geoff who did the design and published all of the necessary files.
BTW I also used a ZRT-80 for many years. Somewhere in one of many moves I lost mine, but would still like to find one again. It was a pick'y design but was affordable. One funny glitch I learned is that it would only work with the Hitachi version of the 6845...
Happy to program PIC's for you, but with a working board it's really easy. Just remove all of the baud rate jumpers and populate the ICSP header. You need a PICKIT3 programmer (there are cheap Chinese knock-off's on Ebay for around $15), the .hex file from Geoff's site and MPLAB IPE (free). I won't tell the Atmel folks...
- Gary
On 10/10/2015 9:21 PM, norwestrzh via N8VEM-S100 wrote:
Great job Gary!!!!
Assembly was *very* easy, and it works!!!! Glad you posted construction notes, and other info. I was wondering about a few things, and they cleared all of that up. The PCB is so small that the hardest part was getting it to "hold still" while I soldered.
This will make a great console for a number of my SBCs.
Takes me back to a project for an ASCII terminal way back when. I think it was called the ZRT-80?? Produced and sold by "Digital Research Computers"? It was a 6.5" x 9"(!) PCB -- bunches of TTL, a Z80A, EPROMs, an 8250 (UART?), and a 6845 CRT driver. As I remember it, basically the same functionality as Geoff Graham terminal -- keyboard (old style (parallel) with maybe a dozen wires) and video. BUT ... the design was pushing the TTL to the limit, so there were some 74S parts required for speed. Mine worked, but it glitched so often (and had to be reset) that it was quite annoying to try to use it. What a difference in 30 or 40 years!!!
Would you consider selling some pre-programmed PICs? I might want to build up other terminals in the future, and I'd really rather not buy the stuff necessary to program the microcontroller. (I'm an ATMEL kinda' guy!)
Roger
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