CubeCell Board: 2 x ADC required

#1

Hi, I have a CubeCell Board that I want to use to use in low power mode to send readings of an analog signal using LoRa.
I want to power it by a coin battery.

I notice that the Cortex 0+ has many ADC channels.

How can I measure both the battery voltage and the analog signal? Is it possible? Or do I need another ADC?

Thanks for your help

#2

You can use this example to measure directly.
#include “Arduino.h”

void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
}

uint16_t voltage;

void loop() {
// put your main code here, to run repeatedly:
pinMode(VBAT_ADC_CTL,OUTPUT);
digitalWrite(VBAT_ADC_CTL,LOW);
uint16_t voltage=analogRead(ADC)*2;
digitalWrite(VBAT_ADC_CTL,HIGH);
Serial.print(millis());
Serial.print(" ");
Serial.println(voltage);
delay(1000);
}

#3

Thank you, could you explain to me what the VBAT_ADC_CTL does?

#4

VBAT_ADC_CTL is the Pin.
image

#5

Thanks for your reply.
I’m a bit confused because here:
https://heltec-automation-docs.readthedocs.io/en/latest/cubecell/frequently_asked_questions.html

it says that a resistor needs to be removed to be able to use the ADC to read external signals instead of the battery?

#6

The CubeCell boards with ASR6501 only have 1 ADC pin.

The ASR6502 series have 3 ADC pin.
https://heltec.org/project/htcc-ab02/
https://heltec.org/project/htcc-ab02s/
https://heltec.org/project/htcc-ab02a/
https://heltec.org/project/htcc-am02/

#7

Ah so to be absolutely clear, if I have an ASR6501 then I absolutely must remove that resistor to use the analog pin for an external signal?

#8

The answer is YES…

#9

Thank you for your help.