Strange ADC Measurements
Posted: Wed Dec 23, 2020 12:24 pm
Hi everyone,
We are trying to measure an 80us wide signal with the ESP32 in DMA mode. Sample rate and accuracy is fine, but it behaves very strange with the peak voltage. The ESP32 seems to have trouble measuring certain voltages. In this case the ESP seems to map a certain range of voltages to 1411mV (Calibrated value with efuse). Has this something to do with how the SAR ADC works?
Any help is appreciated.
Thanks!
Here is how it should (and sometimes does) look like
We are trying to measure an 80us wide signal with the ESP32 in DMA mode. Sample rate and accuracy is fine, but it behaves very strange with the peak voltage. The ESP32 seems to have trouble measuring certain voltages. In this case the ESP seems to map a certain range of voltages to 1411mV (Calibrated value with efuse). Has this something to do with how the SAR ADC works?
Any help is appreciated.
- wrong.PNG (42.1 KiB) Viewed 1265 times
Here is how it should (and sometimes does) look like
- ok.PNG (22.53 KiB) Viewed 1265 times