Hello! Jeff Laughton wrote: > Hi, Michal. Speaking for myself, I'd feel more clarity if the details > were spelled out. At least explain, please, which handshake pins attach > to which (or link to a schematic). You're right, but since the interface works flawlessly with the 6525, my question was more "what is 8255 doing differently?" that "what can go wrong in this interface?" > That makes sense to me, but I'd be looking for the "something" on the > handshake lines (not the data pins of the port). Or maybe I've > misunderstood something -- always possible. It turned out that it was the pin used to generate IRQ on the 6509 after all - it is the only pin in the output port that has a default value of 1, so resetting it to 0 caused havoc. Fortunately, the pin on the 6509 side (FLAG in the CIA) is edge triggered so it should be possible to rewrite everything so that the default value is 0 and it still works. Regards, Michau.Received on 2018-06-10 15:00:26
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