This ADC_MODE(ADC_VCC); is an ESP command, not an Arduino one… in your case you are using the ESP in AT mode which means it is just a simple adapter now and not command accessible as it would be in standalone mode.
This ADC_MODE(ADC_VCC); is an ESP command, not an Arduino one… in your case you are using the ESP in AT mode which means it is just a simple adapter now and not command accessible as it would be in standalone mode.