|Re: More FPGA progress (OT - COSMAC)|
Message #3 Posted by Andrés C. Rodríguez (Argentina) on 9 Aug 2010, 6:13 p.m.,
in response to message #2 by Eric Smith
Back in the last 70s, I was a fan of the CDP1802 and the ELF. I built my own ELF, which is still operable today, with its eight toggle switches using DMA to initialize RAM from console (no ROM monitor needed), a speaker driven by Q, and so on. The original ELF had a couple of HP hex displays that were very nice but also expensive, so I resorted to standard 7-segment displays driven by Mitel 4368 decoders (if memory helps). I bought an 1861 for video, but never found time to put it to work. In fact, in the Memories section of the Museum, in an old article by me, there are photos of my ELF and also of a "chemical process monitor" I developed with the 1802. The fact that it was CMOS captured me, but not to the point of consuming all my hobby money; some was directed to my HP-41C and its accessories.
I would like to know more about your FPGA-based COSMAC, because I became a EE professor, and we have some courses here where the students replicate classic microprocessors using FPGA.
Best regards, congratulations, and thank you for the chance to refresh these memories!