ADC works sometimes STM32f303RE

[JMart.13]

Hi.

I am having problems with the ADC, for some reason, it only works when I put a breakpoint in the function I use to enable the ADC to debug, but, if I run it without any breakpoint, it does not work.

line of code I use to extract a value from the ADC:

sensor_val = periph::ADC12::adc12_get_value();

That function is this one:

static std::uint32_t adc12_get_value(){
	//Start conversion
   
	*reinterpret_cast<volatile std::uint32_t *> (adc1_cr) |= (1U << 2);  //ADC Start
	 while(!*reinterpret_cast<volatile std::uint32_t *> (adc1_isr) & (1U << 2)){} //End of convertion
	 return *reinterpret_cast<volatile std::uint32_t *> (adc1_dr); //extract value
}

and this is the rest of the functions I use for calibration and initialization:

static void adc12_calib_single(){
	//Calibrate the ADC
	adc12_disable();  
	*reinterpret_cast<volatile std::uint32_t *> (adc1_cr) &= ~(1U << 30); 
	*reinterpret_cast<volatile std::uint32_t *> (adc1_cr) |= (1U << 31); 
				
       while((*reinterpret_cast<volatile std::uint32_t *> (adc1_cr) & (1U << 31)) != 0){}
}
			
static void adc12_enable_regulator(){
	RCC->CFGR2 |= (0x16 << 4); 
	RCC->AHBENR |= (1 << 28);
				
	//enable the regulator for the ADC
	*reinterpret_cast<volatile std::uint32_t *> (adc1_cr) = 0; 
	*reinterpret_cast<volatile std::uint32_t *> (adc1_cr) |= (0x1 << 28); 
	periph::SYSTICK::delay_us(10); 
				
				
				
}
			
static void adc12_disable(){
	*reinterpret_cast<volatile std::uint32_t *> (adc1_cr) |= (1U << 1);
	while(*reinterpret_cast<volatile std::uint32_t *> (adc1_cr) & (1U << 0)){}
}
		
static void adc12_init(){
	RCC->AHBENR |= (1 << 28);
				
	//channel 1 with lengnght of 1
	*reinterpret_cast<volatile std::uint32_t *> (adc1_sqr1) = 0;
	*reinterpret_cast<volatile std::uint32_t *> (adc1_sqr1) |= (1U << 6);
	*reinterpret_cast<volatile std::uint32_t *> (adc1_cfgr) |= (1U << 13);
	//enable ADC
	*reinterpret_cast<volatile std::uint32_t *> (adc1_cr) |= (1U << 0); 
	while(!*reinterpret_cast<volatile std::uint32_t *> (adc1_isr) & (1U << 0)){} 
	adc12_get_value(); 
       adc12_calib_single(); 
	*reinterpret_cast<volatile std::uint32_t *> (adc1_cr) |= (1U << 0); 
	while(!*reinterpret_cast<volatile std::uint32_t *> (adc1_isr) & (1U << 0)){} 
}

Thanks in advance

[TDK]

> it does not work

What does this mean in particular? Where is the code stuck?

Consider using the standard CMSIS headers to make the code more readable.

*reinterpret_cast<volatile std::uint32_t *> (adc1_cr) |= (1U << 2);  //ADC Start

vs.

ADC1->CR |= ADC_CR_ADSTART;

[Ons KOOLI]

Hi @Juan Martín Castillo​ ,

Please refer to ADC examples of the STM32CubeF3; under directory: Projects\STM32F303RE-Nucleo\Examples\ADC

Best Regards,

Ons.

[JMart.13]

Hi! well, when I try to debug the variable (without using the breakpoint) it just does not take any value (is like is jumping that function of enabling the ADC). And well, I will try to use the CMSIS, to check.

Thanks for the answer.

[JMart.13]

Hi! thanks, I will check it later!

Thanks for the answer

[JMart.13]

Hi TDK, sorry if I bother you, but I fixed the problem but is strange, I used CMSIS as you suggested and wasn't working but, I changed something:

RCC->AHBENR |= (1 << 28)

I had that line of code to activate the ADC1 and ADC2 and the ADC wasn't working, so I changed it using the macros that the CMSIS library provides:

RCC->AHBENR |= RCC_AHBENR_ADC12EN;

and it worked, that RCC_AHBENR_ADC12EN is the same as (1U << 28U), the only difference is the "U" after the numbers, that makes any difference? like I know that "U" means is an unsigned number, but I don't know if that's a problem if i don't put it

Thanks a lot.

[JMart.13]

Ok, nvm, i have seen that it is 0x1U << 0x28, hum, is strange, anyways, thanks for the answer

[TDK]

One of the major reasons to use the provided CMSIS headers is to eliminate typos like this.

Still not sure what "does not take any value" can possibly mean.