The range of the max197 has to be set. There are 4 ranges,
0 to 5v, -5v to +5, 0 to 10v, -10v to +10v
I suspect the range was set to the latter. This should be explained in the
manual. I have a simple voltage logger program at
http://www.comp.leeds.ac.uk/jj/linux/adc_logger.tgz
There's an executable which should work on the 7250. It has options to set
any of the ranges.
Jim
On Tue, 9 Nov 2010, on the horizon wrote:
> Using the driver from the 'Files' repository, a variable voltage supply
> for testing, and the manual for information; perhaps someone could shed
> some light on why I am getting these results :
>
> If I apply 10v to the proper pins on the Max197 A/D header, the highest
> value I can observe from cat /dev/adc1 is 2047.
>
> The Max197 is a 12 bit converter :
>
> 2^12 = 4096 or 4095
> So, I would deduce that the highest value I could get from the Max197
> though the driver would be 4095.
>
> So, in a nutshell; why am I only getting 2^11 as a maximum value?
>
>
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