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STM32 L4 ADC accuracy

Question asked by Daniel Tarrago on Mar 7, 2017
Latest reply on Mar 8, 2017 by Philippe Cherbonnel

Hello,

I'm working with the STM32L475 micro. In my application I read several analog values using the ADC1. Values read are quite similar when device is in run mode. But, according to my specs and in order to save power, I need to be most of the time in Stop1 mode. Being in this mode, when device wakes-up (periodically, by RTC) is when I carry out these ADC measurements and I wait until ADC has finished measurements to go again to Stop1 mode. In this situation, measurements from ADC are more different than in run mode: I get of about 300mV of diferences between readings and having the same reference at the analog input. When carrying out these measurements, I measure first Vref in order to base other measurements on this figure. Furthermore, ADC reading depend on cycles that are setup. So...

- Which is the best way to manage ADC in this working mode?

- Is it important to auto-calibrate ADC? (I execute 'HAL_ADCEx_Calibration_Start' at the beginning, once ADC is set-up)

- Any other recommendation?

 

Best regards.

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