STM32G030 ADC DMA Not Working

[shohanur00]

Hi all,

I am using STM32G030F6P6 and trying to read ADC channel 11 and channel 16 using DMA.

• ADC works correctly in polling and interrupt mode.

• When I enable DMA, the ADC values in the buffer remain 0 all the time.

• DMA does not trigger at EOC, and DMA transfer never happens.

I have been trying for 1 week, and I cannot understand what is wrong.

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What I have done:

• Configured ADC correctly (calibration, sequence, sampling time, etc.)

• Configured DMA correctly (channel, source/destination, size, circular mode)

• Enabled ADC DMA request (DMAEN)

• Enabled DMAMUX (for STM32G0 series)

But still no data is transferred and buffer remains 0.

#include  "stm32g030xx.h"
#include  "gpio.h"

volatile uint32_t adc_value[2] = {0},adc_buff = 0, adc_index = 0;

void delay_ms(uint32_t ms)
{
    SysTick->LOAD = 64000 - 1;   // 64MHz ? 1ms
    SysTick->VAL  = 0;
    SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk |
                    SysTick_CTRL_ENABLE_Msk;

    for(uint32_t i = 0; i < ms; i++)
    {
        while(!(SysTick->CTRL & SysTick_CTRL_COUNTFLAG_Msk));
    }
}

void RCC_Clock_Config(void){
//Clock Config
RCC->CR &= ~RCC_CR_PLLON;
while(RCC->CR & RCC_CR_PLLRDY);
RCC->PLLCFGR &= ~RCC_PLLCFGR_PLLSRC;   // Clear both PLLSRC bits
RCC->PLLCFGR |=  RCC_PLLCFGR_PLLSRC_1; // 10b ? HSI16
RCC->PLLCFGR &= ~RCC_PLLCFGR_PLLM;
RCC->PLLCFGR |= RCC_PLLCFGR_PLLM_0;
RCC->PLLCFGR &= ~RCC_PLLCFGR_PLLN;
RCC->PLLCFGR |= (16U << RCC_PLLCFGR_PLLN_Pos);
RCC->PLLCFGR &= ~RCC_PLLCFGR_PLLR;
RCC->PLLCFGR |= (1U << RCC_PLLCFGR_PLLR_Pos);
RCC->CR |= RCC_CR_PLLON;
while(!(RCC->CR & RCC_CR_PLLRDY)); 
RCC->PLLCFGR |= RCC_PLLCFGR_PLLREN;

FLASH->ACR &= ~FLASH_ACR_LATENCY;
FLASH->ACR |= FLASH_ACR_LATENCY_2;  // 48–64 MHz ? 2 WS

RCC->CFGR &= ~RCC_CFGR_SW;
RCC->CFGR |= (2 << RCC_CFGR_SW_Pos);
while (((RCC->CFGR >> RCC_CFGR_SWS_Pos) & 0x3) != 0x2);
}

void UART2_Init(void){
RCC->IOPENR |= RCC_IOPENR_GPIOAEN;
GPIO_Init(GPIOA,2,GPIO_MODE_AF,GPIO_OTYPE_PP,GPIO_NOPULL,GPIO_SPEED_HIGH);
GPIOA->AFR[0] &= ~GPIO_AFRL_AFSEL2_Msk;
GPIOA->AFR[0] |= (1U << GPIO_AFRL_AFSEL2_Pos);
RCC->APBENR1 |= RCC_APBENR1_USART2EN;
USART2->CR1 = 0;
USART2->BRR = 556; // 115200 baud @ 64MHz
USART2->CR1 |= USART_CR1_UE;
USART2->CR1 |= USART_CR1_TE;
}

void UART2_Send_Byte(uint8_t c){
while(!(USART2->ISR & USART_ISR_TXE_TXFNF));
    USART2->TDR = c;
while(!(USART2->ISR & USART_ISR_TC)); // wait transmission complete
}

void UART2_Send_Number(int32_t num)
{
    char buf[12];   // enough for -2147483648
    int i = 0;

    if(num == 0){
        UART2_Send_Byte('0');
        return;
    }

    if(num < 0){
        UART2_Send_Byte('-');
        num = -num;
    }

    while(num > 0){
        buf[i++] = (num % 10) + '0';
        num /= 10;
    }

    while(i--){
        UART2_Send_Byte(buf[i]);
    }
}

void ADC_Init(void){
RCC->IOPENR |= RCC_IOPENR_GPIOAEN;
GPIO_Init(GPIOA,10,GPIO_MODE_ANALOG,GPIO_OTYPE_PP,GPIO_NOPULL,GPIO_SPEED_LOW); //ADC Channel 16
RCC->IOPENR |= RCC_IOPENR_GPIOBEN;
GPIO_Init(GPIOB,7,GPIO_MODE_ANALOG,GPIO_OTYPE_PP,GPIO_NOPULL,GPIO_SPEED_LOW);  //ADC Channel 11
RCC->APBENR2 |= RCC_APBENR2_ADCEN;

ADC1->CR &= ~ADC_CR_ADEN;
while(ADC1->CR & ADC_CR_ADEN);

ADC1->CR |= ADC_CR_ADVREGEN;
for(volatile int i=0;i<30000;i++);
ADC1->CR |= ADC_CR_ADCAL;
while(ADC1->CR & ADC_CR_ADCAL);

ADC1->CFGR1 = 0;
ADC1->CFGR1 |= ADC_CFGR1_CONT;
ADC1->CFGR1 |= ADC_CFGR1_CHSELRMOD;

ADC1->CFGR1 |= ADC_CFGR1_DMAEN;
ADC1->CFGR1 |= ADC_CFGR1_DMACFG;
//ADC1->CFGR1 |= ADC_CFGR1_CHSELRMOD;
ADC1->CFGR1 |= ADC_CFGR1_OVRMOD; // overwrite old data
ADC1->SMPR &= ~ ADC_SMPR_SMP1_Msk;
ADC1->SMPR |= (7U << ADC_SMPR_SMP1_Pos);
//ADC->CCR &= ~ADC_CCR_TSEN;   // ?? this is the missing piece

/*ADC1->IER |= ADC_IER_EOCIE;
NVIC_SetPriority(ADC1_IRQn, 0);
NVIC_EnableIRQ(ADC1_IRQn);
__enable_irq();*/

ADC1->CHSELR = ADC_CHSELR_CHSEL11 | ADC_CHSELR_CHSEL16;

ADC1->CR |= ADC_CR_ADEN;
while (!(ADC1->ISR & ADC_ISR_ADRDY)); // ADC ready
//ADC1->CR |= ADC_CR_ADSTART;
}

uint16_t ADC_Read(void){
    //ADC1->CR |= ADC_CR_ADSTART;
    while(!(ADC1->ISR & ADC_ISR_EOC));

    return ADC1->DR;
}

void DMA_Init(void){
RCC->AHBENR |= RCC_AHBENR_DMA1EN;
DMA1_Channel1->CCR = 0;
DMA1_Channel1->CCR |= (3 << DMA_CCR_PL_Pos);  //Priority set very High
DMA1_Channel1->CCR |= (1 << DMA_CCR_MSIZE_Pos); // 16 bits
DMA1_Channel1->CCR |= (1 << DMA_CCR_PSIZE_Pos);
DMA1_Channel1->CCR &= ~DMA_CCR_DIR; 
DMA1_Channel1->CCR |= DMA_CCR_CIRC; //Circularly porbe
DMA1_Channel1->CCR |= DMA_CCR_MINC;

DMA1_Channel1->CPAR = (uint32_t) &(ADC1->DR);
DMA1_Channel1->CMAR = (uint32_t)adc_value;
DMA1_Channel1->CNDTR = 2;
//DMA1_Channel1->CCR |= DMA_CCR_EN;
}

int main(void){
//Clock Config
RCC_Clock_Config();
//GPIO
//__enable_irq();
RCC->IOPENR |= RCC_IOPENR_GPIOAEN;
GPIO_Init(GPIOA,4,GPIO_MODE_OUTPUT,GPIO_OTYPE_PP,GPIO_NOPULL,GPIO_SPEED_LOW);
//ADC
UART2_Init();
DMA_Init();
ADC_Init();
DMA1_Channel1->CCR |= DMA_CCR_EN;   // enable DMA channel
ADC1->CR |= ADC_CR_ADSTART;         // start ADC conversions

while(1){
int16_t adc = adc_buff;
int16_t T = 0;

UART2_Send_Number(adc_value[0]& 0xFFFF);
UART2_Send_Byte('\n');
UART2_Send_Byte('\r');
UART2_Send_Number(adc_value[1]& 0xFFFF);
UART2_Send_Byte('\n');
UART2_Send_Byte('\r');
GPIO_TogglePin(GPIOA,4);
delay_ms(100);
}
}

void ADC1_IRQHandler(void)
{
    if (ADC1->ISR & ADC_ISR_EOC)
    {
        uint16_t val = ADC1->DR;   // MUST read DR to clear EOC

        adc_value[adc_index] = val;

        adc_index++;
        if (adc_index >= 2)
            adc_index = 0;
    }
}

Problem:

The DMA never transfers data and the buffer remains 0.

Even though ADC conversion is running and EOC flag is set, DMA is not triggered.

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Request:

Please help me identify what is missing or wrong in my configuration.

What should I check?

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Thank you.

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Edited to apply source code formatting - please see How to insert source code for future reference.

[shohanur00]

I am not using a dev board.  I am using microcontroller that is attached with my own pcb.  Could you review my code.  

[Andrew Neil]

I would strongly suggest that you first get it working with a known-good example on a known-good board.

[MM..1]

Try start with LL instead bare, after LL work you can rewrite it (i mean waste time)

STM32CubeG0/Projects/NUCLEO-G070RB/Examples_LL/ADC/ADC_SingleConversion_TriggerTimer_DMA_Init at master · STMicroelectronics/STM32CubeG0

good start point

[Michal Dudka · Accepted solution]

If I'm not mistaken, you don't set DMAMUX anywhere. You have to route DMA requests from ADC to your DMA channel.

In other words, how does your DMA channel 1 know that it should handle requests from ADC and not, for example, from UART or SPI?

[shohanur00]

Thank You very much