AnsweredAssumed Answered

VBAT_Mesurement STM32V207 unusual results

Question asked by harald on May 8, 2012
Latest reply on May 9, 2012 by harald

I've used the code from the example VBAT_Mesurement to test the ADC. Instead of connecting a  battery on pin VBAT I've connected VDD 3.3V.

The program requests cyclic the converted value.
VBATVoltage = (ADCConvertedValue*2)*3300/0xFFF;

VBATVoltage  varies from 3287 to 2992. this is a difference  about 8 percent.
I've checked the power VDD with an oscilloscope , which  is quit clean.
There are no peaks visible.

Does anybody know the reason for this ?