CMIS-1 ESP32 Additional ADC Advanced Functions

CMIS (Current Monitor IoT Sensors), SDK Kit is based on an Espressif ESP32 WROOM and uses the internal ADC for reading sensor values.

Other useful advanced ESP32 ADC functions for future experimenting are:

• analogReadResolution(resolution): set the sample bits and resolution. It can be a value between 9 (0 – 511) and 12 bits (0 – 4095). Default is 12-bit resolution.
• analogSetWidth(width): set the sample bits and resolution. It can be a value between 9 (0 – 511) and 12 bits (0 – 4095). Default is 12-bit resolution.
• analogSetCycles(cycles): set the number of cycles per sample. Default is 8. Range: 1 to 255.
• analogSetSamples(samples): set the number of samples in the range. Default is 1 sample. It has an effect of increasing sensitivity.
• analogSetClockDiv(attenuation): set the divider for the ADC clock. Default is 1. Range: 1 to 255.
• analogSetAttenuation(attenuation): sets the input attenuation for all ADC pins. Default is ADC_11db. Accepted values:
  • ADC_0db: sets no attenuation. ADC can measure up to approximately 800 mV (1V input = ADC reading of 1088).
  • ADC_2_5db: The input voltage of ADC will be attenuated, extending the range of measurement to up to approx. 1100 mV. (1V input = ADC reading of 3722).
  • ADC_6db: The input voltage of ADC will be attenuated, extending the range of measurement to up to approx. 1350 mV. (1V input = ADC reading of 3033).
  • ADC_11db: The input voltage of ADC will be attenuated, extending the range of measurement to up to approx. 2600 mV. (1V input = ADC reading of 1575).
• analogSetPinAttenuation(pin, attenuation): sets the input attenuation for the specified pin. Default is ADC_11db. Attenuation values are the same from previous function.
• adcAttachPin(pin): Attach a pin to ADC (also clears any other analogue mode that could be on). Returns TRUE or FALSE result.
• adcStart(pin), adcBusy(pin) and resultadcEnd(pin): starts an ADC conversion on attached pin’s bus. Check if conversion on the pin’s ADC bus is currently running (returns TRUE or FALSE). Get the result of the conversion: returns 16-bit integer.