Friday, December 1, 2017

Interrupt timer added

Not of much interest to ordinary users, but I have added a PIT to handle the timer interrupt, allowing me handle time in a much more efficient manner than reading from CMOS every so often.  Basically it fires off IRQ 0 as often as I need it to.  Originally I wanted to use it to help with overall system timing, but that didnt work out so well.  Maybe Ill revisit that at some point.  But it's good to know it's there when I need it.

Also, as an easter egg, try the following:

POKE 313,255


Its got some issues still, but its somewhat playable.  This wont remain in the build for long, but it will give you an idea of how well the emulation is working.  And why being able to manage the system clock is so important :)


  1. Like the easter egg
    the speaker worked for the first time with this . Only at the end when I died. gave out 2 tones. 1st short, the 2nd lower sound but continuous .Dies cause the pacman image was off to the side. (( ))

    1. The pacman is above the word highscore . Circle of dots.
      the game play area works except you're invisible.

  2. Yeah, agreed. Im not sure how he is doing the pacman sprite, but it doesnt seem to behave the same as the others. Ill have to look into that. As for the sound, youre right - he likely used all three voices for sound and my current implementation only behaves as voice 1 which is missing a bit. I might try to change it to voice 2 or 3 just to see what this game might sound like :) Hopefully soon we can get resid implemented with sound cards.

  3. Sprite 5's x coord has been fixed. You can now see the little pac dude on the screen :)