On Thursday 09 August 2007 21:52, James Knott wrote: > Robert Smits wrote: > > On Wednesday 08 August 2007 19:08, James Knott wrote: > >> Incidentally, many years ago, I bought a huge Cherry keyboard, without > >> any encoder logic. I designed & built my own encoder and used that > >> keyboard with my IMSAI 8080. > > /snip/
As long as we're reminiscing here, I must jump in with this: In 1981 I bought the Big Board CPM computer, which came as a kit of components, with no peripherals. I found a 10" monitor and a keyboard from someplace that had a shift key, but only produced upper-case keycodes. It must have been used with a teletype machine or something similar. Not being a programmer, certainly not in assembler, I built (with some trial and error, since I'm also not a digital but an RF engineer) a converter out of TTL logic to produce both upper and lower case characters under control of the shift key. The Big Board would take parallel keyboard input, as well as serial, so this was not too difficult to do. (Genuine serial k/b's usually only came as part of a terminal, which was pretty darned expensive back in the day.) In another aside, I found, with the help of another engineer who was experienced in video, that the BB was deficient in video bandwidth, so I figured out how to cure that, and wrote it up for the Micro-Cornucopia. They sent me a Tee-shirt, which I still have, marked "AUTHOR". --doug -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
