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BGPierce / VCC

Tandy Color Computer 3 Emulator
GNU General Public License v3.0
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interrupts appear to be edge-triggered instead of level-triggered #1

Open jaggies opened 5 years ago

jaggies commented 5 years ago

While going back and forth between real hardware, I found VCC is tolerant of not clearing FIRQ/IRQ/NMI sources (e.g. forgetting to read GIME register 0xff93 to clear the interrupt). I had to break out the oscilloscope to figure out what was going on. :) Applications that are written correctly don't have a problem, of course, but it makes cross-developing code more challenging since code that works fine on the emulator locks up the real hardware.

BGPierce commented 4 years ago

Sorry for the long wait, but it's been a tough time around here. I understand what you are saying, but I'm not sure of the actions that should happen. Explain as best you can what happens in VCC and a real Coco when the interrupts are not cleared. I'm not a tech or engineer, so the simpler the explanation the better :-)