I think like this...

Right, you can setup the pot to give 2.5V at the input
using a voltmeter. But then what ? Will you always
use a voltmeter when setting the pot ?

What does it matter if the motor stands still with 2.4V
or 2.6V at the ADC input ? The visual difference in the
setting of the pot would probably be very small. What kind
of pot is it ? A regular 1-turn or some 10-turn pot ?

I'd also guess that the differense between the ADC value
with Vpp/2 (5V/2, right?) will be quite small compared with
the theoretical half-range value (according to the datasheet).
Probably just +/- a few bits, after all, that is what the
datasheet specifies. And probably smaller then any visable
difference from the mid-position setting of the pot.

*Or* I must seriously be missing something here. :-)

Jan-Erik.







On 2010-11-21 01:38, James Newton wrote:
> Think about that for just a second?
>
> If I /knew/ the value of ADRES to inject, why would I be trying to find i=
t?
>
> --
> James Newton
> 1-970-462-7764
>
> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf =
Of
> John Temples
> Sent: Saturday, November 20, 2010 16:24
> To: Microcontroller discussion list - Public.
> Subject: RE: [PIC] pickit2 unreliable debug 12F675
>
> On Sat, 20 Nov 2010, James Newton wrote:
>
>> In this specific case: I have a pot connected to AN0 and set so that 2.5=
v
> is
>> on the pin. Now I want to know exactly what ADC count the chip is readin=
g
> so
>> I can set that as the midpoint in my code and turn the motors one
> direction
>> when the voltage is lower and the other when it is higher.
>>
>> With a debugger, I simply read the ADC output register and I'm done.
>>
>> How would you get that value without the debugger?
>
> The simulator has a register injection feature that reads hex values
> from a file that are injected into ADRES over time.
>
> --
> John W. Temples, III
--=20
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