ADC EOC wont go down after reading DR

[marcadell]

Hi,
I already tried to search for previous threads that could help me (like this one), sadly without success.
I'm currently studying the ADC peripheral on STM32F3DISCOVERY from the reference manual. I started writing a simple program to measure a tension on PA0. It all works flawlessly until the ADC samples the value on PA0, stores it in the Data Register and raises EOC. From the manual:
"The ADC sets the EOC flag as soon as a new regular conversion data is available in the
ADCx_DR register. An interrupt can be generated if bit EOCIE is set. EOC flag is cleared by
the software either by writing 1 to it or by reading ADCx_DR." (page 347, Section 15.3.23).
The loop part of my code is the following (I already configured the ADC for single conversion mode, L[3:0] = 0000, DIFSEL=0 and so on... to rule out any problem with configuration):

unsigned int ADC_value = 0;

while(1){

 ADC1->CR |= ADSTART;

//wait for EOC=1

while((ADC1->ISR&EOC) != EOC);

//Data register read

ADC_value = (ADC1->DR);

//custom wait function in ms

wait_ms(1000);

};//end while

};//end main

Executing the program in debug mode clearly shows that DR is updated and EOC is raised.

A possible (dumb, I acknowledge it) workaround that I came up with was setting EOC=0 by S/W, but the program refuses to proceed after the while, no matter what's written next:

unsigned int ADC_value = 0;

while(1){

 ADC1->CR |= ADSTART;

//wait for EOC=1

while((ADC1->ISR&EOC) != EOC);

 ADC1->ISR &= ~EOC;

 ADC1->CR|=ADSTART;

//Data register read

ADC_value = (ADC1->DR);

//custom wait function in ms

wait_ms(1000);

};//end while

};//end main

 

[Ozone]

I cannot remember to have seen this thread on the previous ‘incarnation’ of the forum, but whatever …

What I miss her is the initialisation code for the GPIO and the ADC.
Which usually includes starting an autocalibration.

And second, have you tried to debug your code, and check the peripheral register values in the debugger ?