olix Posted November 19, 2021 Share Posted November 19, 2021 I have a question to which I have not yet found an answer: On the XL boards (and I think also on the XE boards) a bridge "W1" is drawn in the circuit diagram. This connects on the Pokey pin 10 (P4) with pin 11 (P5). On my board this bridge is set with a 0 ohm resistor. I do not understand what function this bridge has and in what cases is it opened? Can someone help me there? Quote Link to comment Share on other sites More sharing options...
Rybags Posted November 19, 2021 Share Posted November 19, 2021 (edited) Fairly sure P4 through P7 are wired together - they're the unused POT inputs that would otherwise go to controller ports 3 and 4 which XL/XE don't have. I would think this is done to force a constant paddle value on those pins, if they were not connected to anything possibly they'd get some random floating value? ed - most software will read the shadow registers - the XL OS mirrors the included port's controller values to the "missing" ones so that games that use those controllers can still have a chance of working. On the 1200XL, one of the POTS has a settable jumper (POT 7 ? ) - likely used at the factory, it can force the computer to go to Self Test when powered on. Edited November 19, 2021 by Rybags 1 Quote Link to comment Share on other sites More sharing options...
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