Read Anolog PIN A3,A4

[rha]

Hi,

i use this simple code for read value from pins anolog input (0-5V) PIN A3 and A4. At pin A3 connect 0V at pin A4 connect stable 2.5 V and reading value.

#define ANALOG_PIN_A3  32
#define ANALOG_PIN_A4  33

void setup() {
  // put your setup code here, to run once:
Serial.begin(115200);
pinMode(ANALOG_PIN_A3,INPUT);
pinMode(ANALOG_PIN_A4,INPUT);
}
int analog_value_3 = 0;
int analog_value_4 = 0;
void loop() {
  // put your main code here, to run repeatedly:
analog_value_3 = analogRead(ANALOG_PIN_A3);
analog_value_4 = analogRead(ANALOG_PIN_A4);
Serial.printf("Current reading on Pin (%d)=%d\n",ANALOG_PIN_A3,analog_value_3);
Serial.printf("Current reading on Pin (%d)=%d\n",ANALOG_PIN_A4,analog_value_4);

delay(2000);
}


At serial monitor i see this result

Current reading on Pin (33)=1889
Current reading on Pin (32)=0
Current reading on Pin (33)=1872
Current reading on Pin (32)=0
Current reading on Pin (33)=1875
Current reading on Pin (32)=0
Current reading on Pin (33)=1875
Current reading on Pin (32)=0
Current reading on Pin (33)=1872
Current reading on Pin (32)=0
Current reading on Pin (33)=1920
Current reading on Pin (32)=0
Current reading on Pin (33)=1872
Current reading on Pin (32)=0
Current reading on Pin (33)=1873
Current reading on Pin (32)=0
Current reading on Pin (33)=1879
Current reading on Pin (32)=0
Current reading on Pin (33)=1872
Current reading on Pin (32)=0
Current reading on Pin (33)=1872
Current reading on Pin (32)=0
Current reading on Pin (33)=1873
Current reading on Pin (32)=0
Current reading on Pin (33)=1888
Current reading on Pin (32)=0
Current reading on Pin (33)=1871
Current reading on Pin (32)=0
Current reading on Pin (33)=1865



VALUE of PIN 4 (33)  is NOT STABLE the value varies, it pulsates +/-20 or more, max 1920 , minimum 1865. It is normaly ? Can i solve it ?

THX

RHA