Computer / Programmazione / Z80 · 12 May 2020 0

LM80C: new firmware release R3.11

Hello everybody. During these days I spent a lot of time working on the firmware of my LM80C computer trying to add features and fixing little bugs within the code. This is the new R3.11 release of the firmware:

  • Changed the way TMR() reads the real time counter so that now continue readings won’t slow down the clock itself anymore: this was due to the fact the at each reading I disabled/re-enabled interrupts because I read 2 single bytes from the memory while now I’m reading a single word at a time, so I don’t need to disable INTs anymore;
  • I also changed the frequency of the keyboard reading. Since this task was very heavy (more than 1,500 clock cycles), instead of doing it each time the interrupt service routine is called (100 times a second), I just execute it 50 times a second, lightening the jobs of the CPU.

Please, grab it from my Github repo: https://github.com/leomil72/LM80C