ESP32 Forum

While using Visual Codes PlatformIO to create a project for an ESP32-C3, I noticed in the 'sdkconfig' file the following setting, however, can not find anything in the documentation:

CONFIG_SOC_ADC_DIGI_IIR_FILTER_NUM=2

Can someone please explain this setting? I did noticed that the ESP-IDF documentation does include information on the IIR filter feature, however, this setting seems to be a little more hardware based. I would like to understand this setting more so that I could maybe find more uses for the implementation of an IIR filter.

Thanks!

It is a hardware feature; there are two IIR filters available in hardware. We propagate that information via CONFIG_SOC_* settings to the menuconfig/sdkconfig system as well, so we can have configuration options that depend on that, rather than on the specific chip model. Obviously, changing this setting won't change the amount of IIR filters available in hardware, so this setting is 'hidden'.