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DevelopmentSega Master System / Mark III / Game Gear |
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Start Button
Overview
The Game Gear has three face buttons: buttons 1 and 2 as in the Master System, and additionally a Start button.
When running in Game Gear mode, the Start button state may be read by inputting from port $00; bit 7 reflects its state, with active-low logic (1 = not pressed, 0 = pressed).
When in Master System mode, the Start button acts identically to the Pause button.
Example code
in a,($00)
cpl ; invert logic so 1 = pressed
and %10000000
ret ; result in a (non-zero if pressed)
cpl ; invert logic so 1 = pressed
and %10000000
ret ; result in a (non-zero if pressed)
