Analog pins go up to 1278 instead of 1023

Using Arduino Microcontrollers
1

I have hooked up my mkr1000 to read thermistors and put out temperature and it's working pretty well, except i'm having trouble calibrating the thermistor probes.

The only point I'm asking to address here, is, that I printed out the adc values of a0, a1 and a2, just to get data on all the inputs to the temperature calculation, and found that at maximum input voltage (3.3v - I checked), the adc values are 1278 on all the pins, not 1023. I have pull-down resistors on the input (currently 15k ohms, but subject to change as I experiment). When I apply gnd to input, adc values go to less than 1.

Does this ring a bell with anyone? Is mkr1000 adc range supposed to be different?

Thanks...

2

gpaCook:
When I apply gnd to input, adc values go to less than 1.

To 0? Or even negative? If last is the case, please show your code, you probably use the wrong type of variable :wink:

Might even solve the other problem but it might not because the MKR1000 supports more then 10-bit ADC resolution. Although it should default t0 10-bit (aka max 1023). See analogReadResolution().

3

MY BAD!! I WITHDRAW THE QUESTION!!

The MKR1000 analog values are correct. When I chose to print out analog values, I printed a variable -"adcAverage" - from a borrowed routine that supposedly derives the average of a group of analog reads. Guess it needs fixing.

Apologies, everyone. :-[