On 2010-07-29 18:56, alan.b.pearce@stfc.ac.uk wrote:
>> No, just the standard "PICkit2 Starter Kit" :
>> http://www.microchip.com/pickit2/
>>
>> The 28-pin demo board in that kit :
>> http://ww1.microchip.com/downloads/en/DeviceDoc/41301A.pdf
>> Scematic at page 9, the pot at the top of fig A-1.
>>
>> It's the voltage drop over R7 that is my concern.
>>
>>
>> Jan-Erik.
>
> Well, I suspect we are at a point where something in your code is
> setting RA0 to an output and setting it low, i.e. writing 0 to both
> TRISA and PORTA.

It's not "my" code. :-)

The code is "lesson 4" in the PICkit2 low-pin-count demo code kit.
I have put a copy of the actual code here :
http://jescab2.dyndns.org/pub_docs/a2d_asm.txt

I tried to do some minor adjustments (only enabling AN0, shutting
WPU off and so on) but no changes at all.



>
> AIUI having a port bit set to analogue doesn't stop it being used as a
> digital output port. This is used to advantage in some sneaky schemes
> for doing things like making capacitance meters, by discharging the cap
> and then using the A/D or comparator to measure the time it takes to get
> to a certain voltage.
>
--=20
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