STM32f407 Triple regular simultaneously mode only: no output in ADC_CDR register

[vis11]

I'm trying to acquire data from 3 sensor simultaneously using Triple Mode. Im using TIM 2 TRGO as a trigger for starting ADC. my data are getting correctly generated in the respective DR registers of ADCs but not in Common register ADC->CDR where it is supposed to have the data

void adc_init(void){

// Enable clock

RCC -> AHB1ENR |= (1U << 0); //Clock For GPIOA

RCC -> AHB1ENR |= (1U << 22); //Clock for DMA2

RCC -> APB2ENR |= (1U << 8); //Clock for ADC1

RCC -> APB2ENR |= (1U << 9); //Clock for ADC2

RCC -> APB2ENR |= (1U << 10); //Clock for ADC3

//Config GPIO

GPIOA -> MODER |= (1U << 2) | (1U <<3); //Analog mode PA1

GPIOA -> MODER |= (1U << 4) | (1U <<5); //Analog mode PA2

GPIOA -> MODER |= (1U << 6) | (1U << 7); //Analog mode PA3

//Triple Mode ADC1, ADC2, ADC3

ADC->CCR |= (0x0016); // Triple Regular Simultaneous Mode

//ADC1 Config

//Select channel

ADC1 -> SQR3 &= ~( (1U << 1) | (1U << 2) | (1U << 3) | (1U << 4));

ADC1 -> SQR3 |= (1U << 0);

ADC1->SMPR2 |= (1U << 0);

ADC1 -> CR2 |= (1U << 28); //Enable External trigger

ADC1 -> CR2 &= ~(1U << 29);

ADC1 -> CR2 |= ( 1U << 28 ); // Enable external trigger on rising edge for ADC1

ADC1 -> CR2 |= ( 1U << 29 );


ADC1 -> CR2 &= ~(1U << 24); // Select TIM2 TRGO event for external trigger

ADC1 -> CR2 |= (1U << 25);

ADC1 -> CR2 |= (1U << 26);

ADC1 -> CR2 &= ~(1U << 27);

ADC1 -> CR2 |= (1U << 0);


// ADC1 -> CR2 |= (1U << | (1U << 9); // Select to use DMA


//ADC2 Config

//Select channel

ADC2 -> SQR3 &= ~( (1U << 0) | (1U << 2) | (1U << 3) | (1U << 4));

ADC2 -> SQR3 |= (1U << 1);

ADC2->SMPR2 |= (1U << 0);

ADC2 -> CR2 |= (1U << 0);



//ADC3 Config

ADC3 -> SQR3 &= ~( (1U << 2) | (1U << 3) | (1U << 4));

ADC3 -> SQR3 |= (1U << 0) | (1U << 1);

ADC2->SMPR2 |= (1U << 0);

ADC3 -> CR2 |= (1U << 0);



/* CONFIG TIMER FOR TRIGGER */

RCC -> APB1ENR |= ( 1U << 0); // Enable clock for TIM2

TIM2 -> PSC = (8400 - 1); // Set prescaler for 10000Hz timer frequency

TIM2 -> ARR = (1000-1); // Set auto reload value

TIM2 -> CR2 &= ~(( 1U << 4) | ( 1U << 6)); // Select update event for TRGO
TIM2 -> CR2 |= ( 1U << 5);

}

void adc_start(void){

TIM2 -> CR1 |= ( 1U << 0); // Enable TIM2

}

[TDK]

How do you know? You don't read DR or CDR anywhere in the code shown.

By "not output" do you mean that it reads as 0?

[vis11]

This is just configuration I've done for Adc. I tracked the status of CDR register through debugging. It always stays 0. The CCR has the valu 0x016 has CSR updates according to ADC status. The Data are available in the ADCx DR registers but not in CDR

[waclawek.jan]

Maybe it's not obvious from the description of that register, but ADC_CDR is intended to be read out by DMA, thus it is not "populated" until you set ADC_CCR.DMA to other than 0b00. 

For Triple Regular simultaneous mode only, you are supposed to set it to 0b01, according to the narrative, and then use DMA accordingly; although it appears to work somehow also with 0b10 and also when polling fast enough (if you know which flag(s) to poll).

As with "single" ADC usage, you have to pick the data timely, otherwise it will overflow and stop converting.

JW

[vis11]

Which ADC's DMA controller should i use. If i use ADC1 DMA stream can i use it fetch data from ADC_CDR. Also do i have to enable all the ADCs for DMA transfer

[waclawek.jan]

0. When posting code, use the "</>" icon at top of the editor

1. Enable DMA clock

RCC->AHB1ENR |= RCC_AHB1ENR_DMA2EN;

2. Make sure the adc_data[] array is not located in the CCMRAM (ie. it's in RAM, above 0x2000'0000)

3. Make sure DMA2_Stream0 -> NDTR is set to the size of adc_data array (and don't OR into this register, write to it directly )

4. Uncomment setting of memory increment, DMAx_Streamx_CR.MEMC bit:

DMA2_Stream0 -> CR |= (DMA_SxCR_MINC); //Enable Mem Inc

5. Comment out/remove enabling DMA individually in ADC1_CR2 and ADC2_CR2.

JW

[SofLit]

Hello @vis11 and welcome to the community,

First, use </> button to paste your code. Read the following tips on how to post a thread in this community.

Second, please don't duplicate threads for the same subject.

Thank you for your understanding.

[vis11]

my apologies for the mistakes as its my first time here and i was not familiar with the rules

[vis11]

now when i use the DAM Mode 1 in ADC_CCR register, the ADC_CDR is only getting the ADC3 values but if i use DMA Mode 2 ALL values are generating by pairs on ADC_CDR register. I've tried to debug but can't seems to find the problems. The code is given below:

/*
 * adc.c
 *
 *  Created on: Sep 21, 2024
 *      Author: Vishnu
 */

#include <adc.h>

volatile uint32_t adc_data;
volatile uint16_t dma2_status;


void adc_init(void){

	//Enable Clock
	RCC -> AHB1ENR |= RCC_AHB1ENR_GPIOAEN;
	RCC -> AHB1ENR |= RCC_AHB1ENR_DMA2EN;
	RCC -> APB1ENR |= RCC_APB1ENR_TIM2EN;
	RCC -> APB2ENR |= RCC_APB2ENR_ADC1EN;
	RCC -> APB2ENR |= RCC_APB2ENR_ADC2EN;
	RCC -> APB2ENR |= RCC_APB2ENR_ADC3EN;

	//Set PA1, PA2, PA3, as Analog port
	GPIOA -> MODER |= (GPIO_MODER_MODER1_0) | (GPIO_MODER_MODER1_1);
	GPIOA -> MODER |= (GPIO_MODER_MODER2_0) | (GPIO_MODER_MODER2_1);
	GPIOA -> MODER |= (GPIO_MODER_MODER3_0) | (GPIO_MODER_MODER3_1);

	// Configure ADC

	//ADC1
	ADC1 -> SQR3 = (0X01);  // Select Ch 1
	ADC1 -> CR2 |= (ADC_CR2_EXTEN_0);  // Enable External trigger
	ADC1 -> CR2 &= ~(ADC_CR2_EXTEN_1);

	ADC1 -> CR2 &= ~( (ADC_CR2_EXTSEL_0) | (ADC_CR2_EXTSEL_3));  // Select TIM2 TRGO event
	ADC1 -> CR2 |= (ADC_CR2_EXTSEL_1) | (ADC_CR2_EXTSEL_2);

	ADC1 -> CR2 |= (ADC_CR2_ADON);  //Enable ADC1

	//ADC2
	ADC2 -> SQR3 |= (0X02);  // Select Ch 2
	ADC2 -> CR2 |= (ADC_CR2_ADON);  //Enable ADC1

	//ADC3
	ADC3 -> SQR3 |= (0X03);  // Select Ch 3
	ADC3 -> CR2 |= (ADC_CR2_ADON);  //Enable ADC1



	// Config DMA2
	DMA2_Stream0 -> CR &= ~(DMA_SxCR_EN);  //Disable DMA
	while(( (DMA2_Stream0 -> CR) & (DMA_SxCR_EN) )){}  // Wait till stream is disable
	//Select Ch0
	DMA2_Stream0 -> CR &= ~( (DMA_SxCR_CHSEL_0) | (DMA_SxCR_CHSEL_1) | (DMA_SxCR_CHSEL_2) );

	DMA2_Stream0 -> CR |= (DMA_SxCR_PL_0) | (DMA_SxCR_PL_1); // Set very high Priority level

	DMA2_Stream0 -> CR &= ~(DMA_SxCR_MSIZE_0);  //Set MSize 32-bit
	DMA2_Stream0 -> CR |= (DMA_SxCR_MSIZE_1);

	DMA2_Stream0 -> CR &= ~(DMA_SxCR_PSIZE_0);  //Set PSize 32-bit
	DMA2_Stream0 -> CR |= (DMA_SxCR_PSIZE_1);

	DMA2_Stream0 -> CR |= (DMA_SxCR_CIRC);  //Enable circular mode
	DMA2_Stream0 -> CR &= ~( (DMA_SxCR_DIR_0) | (DMA_SxCR_DIR_1));  //Set transfer direction

	DMA2_Stream0 -> NDTR |= 1;  //Set no.of data register
	DMA2_Stream0 -> PAR = (uint32_t) (&(ADC -> CDR));  //Set Peri Address
	DMA2_Stream0 -> M0AR = (uint32_t) (&adc_data);  //Set Mem Address

	// Enable DMA transfer complete interrupt
	DMA2_Stream0 -> CR |= DMA_SxCR_TCIE;  // Enable transfer complete interrupt

	// Enable DMA interrupt in NVIC
	NVIC_EnableIRQ(DMA2_Stream0_IRQn);

	/* CONFIG TIMER FOR TRIGGER */
	TIM2 -> PSC = (8400 - 1);  // Set prescaler for 10000Hz timer frequency
	TIM2 -> ARR = (10000-1);  // Set auto reload value

	TIM2 -> CR2 &= ~(( 1U << 4) | ( 1U << 6));  // Select update event for TRGO
	TIM2 -> CR2 |= ( 1U << 5);

	ADC -> CCR |= (ADC_CCR_DDS);  //Set Contin DMA Request
	ADC -> CCR |= (ADC_CCR_DMA_0);  //Set DMA Mode 1
	ADC -> CCR |= (0x016); // Enable Dual Mode


}


void adc_start(void){

	DMA2_Stream0 -> CR |= (DMA_SxCR_EN); // Enable DMA
	TIM2 -> CR1 |= ( TIM_CR1_CEN);  // Enable TIM2

}

// Interrupt Service Routine for DMA2 Stream 0
void DMA2_Stream0_IRQHandler(void) {
    // Check for DMA transfer complete interrupt flag
    if(DMA2->LISR & DMA_LISR_TCIF0) {
        // Clear the interrupt flag
        DMA2->LIFCR |= DMA_LIFCR_CTCIF0;
        // Set flag to indicate that the transfer is complete
        dma2_status = 1;

    }
}

[waclawek.jan]

I don't quite see how would the "common" ADC data register output ADC3 result in Dual Mode (which involves only ADC1 and ADC2).

Why don't you make the adc_data a relatively large array, for example 300 words - and then set DMA's NDTR to 300, too. That would allow you to observe a longer sequence of data at once.

JW