On Sun, 1 Aug 2004 11:55:24 -0400, csblondin@SYMPATICO.CA wrote:

> Though having an interrupt happening between the set GIE and RET would need quite a big piece of luck!

Errr - not really!  If PICs work the way of other micros I've used (and I'm open to being corrected here), the
GIE only masks the interrupt-causing event from being seen, it doesn't "stop it happening".  So if an
interrupt-causing event happened while GIE was clear, as soon as you set it the interrupt will occur.
Consequently there's a really good chance of it happening just when you don't want it, which is why the RETFIE
sets GIE "after" the return.

Enabling an interrupt too early is a classic "trap for the unwary"  :-)

Cheers,



Howard Winter
St.Albans, England

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