Re: XADC values read from VAUX0-15 are consistently ~10% less than they should be

[Xander Huff <xander.huff@ni.com>]

On 5/5/2015 5:11 PM, Xander Huff wrote:
> Hi Lars,
>
> I've been working on transitioning one of our hardware devices over from using
> the out-of-tree hwmon driver that Xilinx used to provide to the xadc driver you
> added upstream, but I've been having trouble accessing our connected auxiliary
> channels. I've found that for all channels I've tested, after multiplying the
> raw value by the scale value (0.244140625), the resulting mVs are always about
> 10 percent less than what we expect them to be. (2.9V instead of 3.3V, 5.4V
> instead of 6V, etc.). I'm interested in any tips you may have on how to debug
> this issue.
Nevermind, it turns out I had somehow transcribed the scale value incorrectly 
for my testing. After modifying my test to directly use the scale values from 
our target, the resulting voltages came out as expected

-- 
Xander Huff
Staff Software Engineer
National Instruments