Tags » RetroChallenge
After the tribulations of the last few days, I decided to change the program to display the value in the IC3 captured-value register (TIC3) – the last value of the free-running 16-bit hardware cycle-counter when the most recent IC3 pin-event occurred. 731 more words
Following on from the “final solution” plan described in the previous episode, the first step is to try to simulate incoming keyboard-clock interrupts.
This can be done by using a pin of the output-only PORTB on the 68hc11 directly connected back to the input-capture pin concerned, and then to drive that output pin under software control. 555 more words
At the lowest level PS/2 keyboard interface is an active-clocked packetised serial bitstream using open-drain drivers, running at 10KHz-30KHz (frequency depends on keyboard, and can vary somewhat at runtime!). 463 more words