Well, like I said, the data sheet on this 12F629 says <b>When MCLR is asserted in INTOSC or RC mode, the internal clock oscillator is disabled.</b>

Perhaps the question is, what does "asserted" mean in this case? To me, it means that if you use MCLR=ON then it disables those two clocks. If it means anything else then enlighten me please!

I put MCLR=ON in the programmer. I am certain it programs it correctly otherwise that issues would have come up long before now with their programmer.

Here were my tests:

MCLR=NO / OSC=ON : Everything worked fine with nothing on the MCLR pin

MCLR=YES / OSC=ON: Everything worked fine so long as I had 5v on the MCLR pin. If I removed power to that pin everything stopped.

So, there is a clock ticking somewhere. How does it all work?

Bart