This should be easy, but I can't get it to work- I'm trying to put
the PIC to sleep and wake up on keypress, but the PIC won't wake up.

I looked in the FAQ and all, but no joy, so here is the situation:

I'm using Port B to scan a 16 key matrix.  RB0..3 are active low scan
lines, RP4..7 are the read back lines, RBPUs active.  All OK, been
there, done that, decoded it, have the T-shirt :)

I want to put the PIC to sleep and wake up on any key press.

So, I set the scan lines all active (RB0..3 are low),
(I checked- they are low)
I TRIS port A and C for minimum current draw, but I don't TRIS port B.
Then I:
-mask my other interrupt sources
-read PortB to set the current state (RB4..7 are high).
-clear the RBIF
-enable the RBIE
-enable GIE
-SLEEP

PIC is asleep, the osc stopped.

I never wake up when a key is pressed.  Clearly, PORTB is changing
state, I can see it on the scope, nice low level on a previously high
RB7.  I can jiggle that port all I want and it won't wake up or reset.

Target is a 16LC76/JW with a blindfold over its window.

I can run the code right up to the point of the SLEEP under emulation
(PICMASTER), and all the FSRs are set as I outlines above.  If I hang
in a loop like:

here: goto here

...instead of executing the Sleep, The PIC gets the interrupt, the
ISR runs, and I "wake up".

I thought maybe the PICMASTER was unable to wake from sleep under any
circumstance, but I burned a real chip with the same code, and it
won't wake either.

Which stupid thing did I forget?

Thanks all,

Barry.
------------
Barry King, KA1NLH
NRG Systems "Measuring the Wind's Energy"
http://www.nrgsystems.com
Check out the accumulated (PIC) wisdom of the ages at:
PIC/PICList FAQ: http://www.piclist.org