IOC flag triggered when PIC is unplugged...?

[Demon]

These are pushbuttons, not rotary encoders with wonky shafts that can jitter whenever the cat farts.

[Demon]

I'm certain it has something to do with voltage levels as the PIC loses power.

IOC flags are randomly triggered when VDD is cut with a switch, but not on MCLR.

Values are READ from DATA at PIC start-up. IOC flags on pushbuttons are used to swap values left to right, then WRITE back to memory.* By the end of the video, all values have swapped places without pushing any buttons.

[richard]

Ceramic bypass/decoupling capacitors are often better .

IOC flags on pushbuttons are used to swap values left to right, then WRITE back to memory

a particularly bad practice, you should always check that it was an actual keypress [ in that was held for a definitive time] before actioning it

key activity should be ignored until power is stable

[Demon]

Ceramic bypass/decoupling capacitors are often better ...

I have 0.1uF on VDD/VSS pins, 0.1uF on the switch input pins and 0.01uF on the encoder input pins; all ceramic caps.

...a particularly bad practice, you should always check that it was an actual keypress [ in that was held for a definitive time] before actioning it...

That's what the IOC flag was used for; to check if a button was activated. If I'm going to have to check if a key has been pressed, IOC is of no advantage to me. I didn't understand why you guys were not in favour of using IOC for this, but now I'm understanding a lot better why it wasn't good idea.

I've already gutted the IOC code and I'm checking the pins for change in value. Those 4 SWAP buttons were the last ones, and then I noticed things were going wacky with my stored data.

... key activity should be ignored until power is stable

I always have at least PAUSEUS 200 at program startup. I have no idea how to check if power is stable on shut-down.


I've given up on the 16F18877; I had switched to these for IOC, internal pull-ups and Schmitt Trigger features. But they're much more finicky than a 16F1937 with external pull-ups, 74HC14 ICs and just polling the pins in MainLoop.

The 16F1937 is like a tank; less fancy but it keeps on trucking.