[sdiy] while we're talking about scaling & biasing etc

[Tom Wiltshire]

I agree with Jerry; I'd suspect some software set-up problem rather  
than hardware. It's very easy to forget one setting in some register  
somewhere and then spend two days trying to work out what's wrong  
with the circuit. At least, I seem to think so!

T.

On 24 May 2009, at 04:48, Jerry Gray-Eskue wrote:
>
> A few of possibilities occur to me off hand,
>
> 1 The Micro you are using has an analog input mux and it is looking at
> different pin.
> 2 The D2A is not setup correctly and so is not reading the voltage  
> on the
> pin. This setup can be tricky with a number of registers and bit flags
> involved.
> 3 The Port Pin you are using has not been configured as an analog  
> input.
> 4 You are setup for an External Reference and this reference  
> voltage is
> missing.
>
> With only one ground you should be reading the voltage value on the  
> pin,
> check the voltage on the Input Pin to the Ground Pin of the  
> uprocessor, this
> is what the converter will see.
>