52833-DK ADC demo program - not reading voltages

[Mark Samarin]

I am running the ADC demo for the 52833-DK (pca10100) and can’t seem to get any valid readings.  SDK 16.0: examples\peripheral\saadc 

I am applying 1.5V  to AIN0 on P8 and the readings are all around x23 counts.    I tried moving to AIN2 (sw change) with no luck.  I then went back to AIN0 and moved the 1.5V stimulus to each AIN channel to see if maybe there was a label misprint or something.    I have 2 boards and tried both with the same results.

I verified NRFX_SAADC_ENABLED=1 in sdk_config.h

 I went through and verified all of the ADC registers in the debugger and they look correct to me (single-ended, p-connected, n-disconnected, 10-bit, internal reference, Gain = 1/6, etc).  The ADC is sampling;  I see small changes in the readings, and I can change the reference to Vcc/4 on the fly and the readings will drop by 8 counts or so.

 Do I need to do something on the DK board to get analog readings? 

[tesc]

Hi,

The example seems to work on my desk. What values are you reading, and what values do you expect?

Pin used in the example is P0.02. For unchanged example, GND should be at around 0, VDD (2.8V) at around 850.

Regards,
Terje

[Mark Samarin]

I see the problem   A0 = Ain1 (not Ain0) , etc.  Got it now.