Okay, I think I found something, that may be a bug somewhere...

I got a hold of another fresh 16F88, which I successfully programmed with the 
ICD2 clone and MPLAB.  But I was careful to set MCLR to ON (so it functions 
as a reset pin, AND to set the oscillator to external.  But there is a 
problem -- with MCLR tied to +5V, it started working (blinking LEDs) without 
an R & C on the CLKI pins.  Code is here... 
(http://www.narwani.org/neil/electronics/f88-test.asm).

The OSCO pin gave me a frequency of ~7.5khz, which means the device was 
running at a clock rate of ~30 khz.  Interestingly close to 31.25khz, isn't 
it?

Now, in that code, you'll notice I don't bother setting the IESO config bit -- 
the F88 datasheet says when using anything other than HS, XT, or LP, then 
2-speed startup mode is disabled.  Apparently not so, cause I made only one 
change -- to explicitly set IESO to off, using "__CONFIG _Config2, _IESO_OFF 
& _FCMEN_OFF", and now the device works as expected -- requiring an R and C 
on the CLKI pin to function properly.

It's possible that the issue lies with the creation of the hex file, or with 
the programming the chip, but I suspect a bug in the chip, which is not 
mentioned in the errata doc.  I still intend to check where this problem is 
(just need to dig up a reference to the hex file format and compare the 
files).  At least now I'll know to keep the MCLR pin function on.

My other issue now is how to deal with the 2 F88 chips I have that are locked 
out, then I'll deal with the F818/9 later.

Cheers,
-Neil.



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