8 years, 1 month ago.

STM32L476G nucleo ADC reading error

I bought a STM32L476G nucleo board.I started to write code in Keil MDK-5 with the help of Hal drivers from STM32Cube MX.I coded for some Blinky and Usart successfully.But as i moved to ADC,i faced a strange problem.From the board schematics,i found that the MCU is using 3v3 external Vref.I measured with a multimeter and found 3.29v.I then coded a program to display the ADC read value via Usart.As the ADC of the STM32 is 12 bit,it should return 4095 while reading 3.3v.But whenever i am connecting PA0(Analog ADC pin 5/Pin no-14) to 3.3v,it is returning value between 4025 to 4028.I tried to average of 100 results but got same output.Also i tried with different clock speeds but had no luck.

My question is if the error(typically 1.63% to 1.71%) is normal or if my adc unit is faulty or am i missing something????I found very little help about L476G as the controller is very new.Please reply guys...