Monthly Archives: October 2013

PS/2 Keyboard Decoder

I have run into a problem with the decoder software.  I have read many posts on how to turn the keyboard LEDs on and off but they stubbornly remain off.  Normally interfaces to a PC are extensively documented by multiple sources and widely available.  I’m surprised by how little accurate information is available.  This includes some waveforms (diagrams, not captures) that have the wrong number of clock pulses in the transmitted data.  I have been busy recently and unable to work on the issue but during the past week I got back to it and rewrote the code to toggle the LED once more and it still doesn’t work.

Since I can’t find reliable information I will have to measure it.  I bought a few cables, connectors and set up a test PC to talk to the keyboard.  I will capture the waveforms and publish them here so that there is a trustworthy source of information.