Reference voltage control for the ADC

Is there any way to control the voltage reference for the ADC in the spark core? I have some signal wander in positive and negative domains.

Hi @miska

The reference voltage for the ADC is tied to a filtered version of 3.3V and is not changeable. The STM32 ARM does not allow negative voltages anyway.

You have two choices:

  • You can add an op-amp or two to do signal scaling and center the range on 1.65V
  • You could try AC coupling the input with clamping diodes.

Can you say more about the signal you are measuring? Fast? Slow? What voltage range?

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