5 years, 3 months ago.

AnalogIn on pin A3 on Nucleo-L432KC

Hi

I have defined pin A3 as an analogIn and DewPoint as a variable as follows in my code:

AnalogIn DP_In(A3);
float DewPoint = 0;

I am also using a 16x2 LCD that has been setup as follows:

TextLCD lcd(D6, D9, D2, D3, D4, D5); // rs, e, d4-d7

I then have a loop that reads the A3 pin every 1 second with the following code:

 DewPoint = DP_In.read()*100.0f;

I have set the input voltage to pin A3 to 2,8V.

I expect to have a constant value for DewPoint as a percentage of 0-3.3V.

The value that I receive is not constant it is fluctuating between 83% and 88% with every read. This value should be constant in line with my 2.8V input signal. What am I doing wrong?

• Can Pin A3 be used as analogue input?
• Is there a problem in my code?
• Is it possible that my screen is interfering with me analogue readings?
• Which pins do you recommend I use?

Your assistance is much appreciated.