Sources for 8b TTL keyboards (Keytronics)

Sources for 8b TTL keyboards (Keytronics) ROBO5.8 robo58 at optonline.net <mailto:cctalk%40classiccmp.org?Subject=Sources%20for%208b%20TTL%20keyboards %20%28Keytronics%29&In-Reply-To=20081124113652.A53673%40shell.lmi.net> Thu Dec 4 10:03:11 CST 2008 * Previous message: Free ZX81 kits... * Next message: Sources for 8b TTL keyboards (Keytronics) * Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] ________________________________ Hi Folks, It's been interesting taking out my old CP/M stuff and getting it operational again. My system uses an 8bit TTL Keytronics Capacitive Sense keyboard. It was operational for about an hour and then it quit. It turns out that the keyboard uses little sponge pads to hold the capacitive disks and they have biodegraded into dust. So I went looking for an old 8b TTL replacement keyboard. So far no luck. I also looked for a black box solution that would take an AT or PS/2 keyboard and convert it to a parallel port output. So far no luck. So let me turn to the experts and ask for advice and suggestions. Please advise Robo -----REPLY----- Hi! I feel your pain on trying to obtain parallel ASCII keyboards. They are not easy to find and sometimes when you do they are not compatible or require extensive modifications to work. My suggestion is to use a PIC (16F628) to implement a simple serial to parallel converter. I did this to with a PIC to convert a spare broken KayPro II keyboard (300 bps serial) to 8 bit parallel with strobe for use with a Vector Graphic FlashWriter II parallel keyboard interface. The same could be done with an XT or AT (PS/2) keyboard although a bit more complex. The software source code examples available on the internet. One of the N8VEM builders (James) just did a project to add a AT (PS/2) keyboard to the N8VEM SBC so that might be a good place to start for a source code example. Thanks and have a nice day! Andrew Lynch