Barry Gershenfeld wrote:
>
> We just fired up a board with a 12C671, and of course it didn't
> work.  How you debug a chip like that, I think you have to
> do it by staring at it...(I'm gonna look at the C compiler
> output)
>
> What bothered me above all is that the output pin showed 0 volts.
> I mean 0.000 volts.  Is something wrong with this picture?  Is
> there a technology (FET, etc.) that would give a real low
> state of 0 volts?  It's not shorted (we measured several K
> to ground) and the PIC has power.

Could be quite normal for the output pin to be that
low depending what current it is sinking. Very low
currents sunk give very low sat voltages.

If you want to test the output pin, add a 1k pullup
resistor to 5v. This will make it sink about 4-5mA.
The low voltage will then be about 0.3 - 0.4v typical,
(datasheet claims 0.6v max for 8.5mA sunk).
-Roman

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