Alice Campbell wrote:

> no, but it resets the tris and option registers to ones.

This should not occur for a WDT or MCLR reset. The TRIS registers should
remain as they were. The OPTION register does change to all 1's though.

> it is more subltle than even that.  if wdt is set on _mclr, then it
> will think its powerup reset. you have to set a flag on powerup and
> read that to distinguish a true powerup from a _mclr   or clrwdt
> trigger.

If a MCLR reset occurs then the status bits TO and PD will not change.
If these bits were altered by some other event, eg. WDT timeout, then on
reset you may missinterpret these bits.

I don't know how you can distinguish a MCLR reset.

On a true power up, you cannot guarantee that the powerup flag is not
set by a random number appearing in RAM.

--
Best regards

Tony

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