Friday, September 21, 2007

Inputs



I had to hack the game code to jump to the operator mode. The only way to normally get to this screen is to open the door and press the "Self Test" button. Since I don't have inputs yet, I force the code to jump there.


This allows me to see what happens when messing with the inputs via the keyboard.


After a lot of digging I found that the Inputs seem to address external ram at #A000. There is also inputs at #8000.


After fuzzing around with the values, I found that the #A000 region is split into 2 banks. The high nibble stores 8 inputs and the low nibble the other 8. This covers banks B and C.


The #8000 region seems to handle the bank A but since these are not buttons, they need to be treated differently. This area is gonna need help eventually. But for now I have all 3 banks working but not the dip switches.

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