Keyboard PS/2 to Parallel converter

Thats a pretty short strobe --- although it will be perfectly acceptable on many systems - Others will "go away" to process a key strobe, and may miss the next key if the strobe is short (in certain applications yadda yadda ...) [An example of where this occurs badly is in polled CTRL-C processing on some systems - you need to hold CTRL-C until the software notices that you have a key down - normal operation on polled systems does this to a lesser extent, but it helps to have a long strobe if you don't have a true key-down strobe] Most of the parallel keyboards I've worked with use a true "key down" strobe which stays asserted until you let go of the key - so I like to provide that capability. As noted above, thats a shortish strobe, and given that the keyboard clocks the transfer, you don't really have control over how fast the next data can come in other than "they are supposed to do it somewhere near this rate", but yes - with a short strobe you can in most cases get away with this technique. As a simple approach, this will work as long as the timing fits ... and it is an easy way to do it - you actually need to "undo" some of the PC's nice keyboard features to implement more robust emulation... (I had to "undo" the auto-repeat by ignoring multiple-key downs without key-ups in my PC100 emulator when the "auto-repeat" option is turned off). I should point out that auto-repeat and a true key-down indicator are somewhat multually exclusive - If you want the indicator to stay asserted as long as a key is held down, then having it auto-repeat is contrary to that ... this is why many parallel keyboards have a separate "REPEAT" key - this key simply interrupts the key-down indicator at a regular rate while it is held down. Which is fine for many applications - A generalized parallel keyboard emulation should allow for either case, and you will need to handle the things I mentioned (which isn't hard). Regards, Dave -- dave06a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Collector of vintage computing equipment: http://www.classiccmp.org/dunfield/index.html