ESP8266 Community Forum

songa wrote:Both are correct...
And it was exactly in this way that I mounted the circuit being analyzed here.

so you removed the resistors connected to pin A0 on esp-12 module on NodeMCU board?

schufti wrote:

songa wrote:Both are correct...
And it was exactly in this way that I mounted the circuit being analyzed here.

so you removed the resistors connected to pin A0 on esp-12 module on NodeMCU board?

Follows the diagram of all the external and internal connections of the circuit in question.
It can be seen that there is no connection on pin A0 of the NodeMCU.
I am using only pins D1 and D2, to connect to ADS1115.

A0 or ADC (that's what it is called in the schematic) of the ESP-12 module is connected to junction R9/R11 on the NodeMCU board. Especially R11 leading to gnd is interfering with ESP.getVcc();

alternatively you could connect ADC_EX pin of the NodeMCU board to 3V3pin and do an analogRead(A0) to get a reading on Vcc, or connect via 180k resistor to Vin to get a reading on raw voltage (up to 5V). For higher Vin use (Vin-1)*100-220 in kOhms.

schufti wrote:A0 or ADC (that's what it is called in the schematic) of the ESP-12 module is connected to junction R9/R11 on the NodeMCU board. Especially R11 leading to gnd is interfering with ESP.getVcc();

alternatively you could connect ADC_EX pin of the NodeMCU board to 3V3pin and do an analogRead(A0) to get a reading on Vcc, or connect via 180k resistor to Vin to get a reading on raw voltage (up to 5V). For higher Vin use (Vin-1)*100-220 in kOhms.

Okay, now I understand what's happening here...
Maybe because my native language is not English, I did not get it right the first answers!
At first, I believed that the NodeMCU module was treated as something only one...
But now I realize, that the ESP8266 may be a reference to the part, as was the case here!
So, I understood that the interference happens inside the module (NodeMCU), through the
resistors inside the module itself and not, through the input A0 of the module in question!

thank you very much guys and sorry for the misunderstanding