Am Sonntag, 2. Oktober 2022, 00:02:20 CEST schrieb Craig Taylor: > From the schematic, what is the wiring for the Joystick Port? I"ve got a > 128 w/ a chip labelled Partner 128 but have never figured out quite what > it's useful for. When I re-setup the system next would love to know to > trigger it. Its really kindof weird. The cartridge has a circuit to listen to the address bus. The button "arms" the circuit and issues a NMI, and when there is $fffa it forces $de on the databus. Now a side effect of how the keyboard scanner works is that you get a 60Hz pulse on some pin(s) on the joystick port. This pulse is now used to "disarm" the NMI logic. -- http://hitmen.eu http://ar.pokefinder.org http://vice-emu.sourceforge.net http://magicdisk.untergrund.net Education is what you have left when you have forgotten everything you learned in school. <Albert Einstein>Received on 2022-10-02 20:00:03
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