Posted on April 22, 2017 at 16:17
Hi, I am trying to use ADC with DMA on the STM32F407 in two channels (PA1 and PA2), so, basically I created the project using CubeMX, exported it to Coocox, ran the debug to fill the vector and imported these points from Matlab to see the signal wave.
The signal that I�m taking is from the electrical network (127 VAC/60 Hz), attenuated by a transformer and a resistor divider, and added a bias through another resistor divider and a capacitor.
The problem is showed in the image below, where appears something like a discontinuous point, and its occurs in different times of the wave:
Voltage Wave (V Vector)
I have changed the settings of ADC and DMA many times but no success.
I will put the mainly code if you need the whole code just me know.
&sharpdefine Length 256
uint32_t Amostras[2*Length]; //Vector to Samples
uint32_t V[Length]; //Voltage samples
uint32_t I[Length]; // Current samples
int main(void)
{ /* USER CODE BEGIN 1 */ int i =0; HAL_ADC_Start_DMA(&hadc1, Amostras, 512);while (1)
{ //4095 = 2.92 V i=0; while(i<Length){ V[i] = Amostras[2*i]; I[i] = Amostras[(2*i)+1]; i++; }}
void MX_ADC1_Init(void)
{ ADC_ChannelConfTypeDef sConfig; /**Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion) */ hadc1.Instance = ADC1; hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV4; hadc1.Init.Resolution = ADC_RESOLUTION_12B; hadc1.Init.ScanConvMode = ENABLE; hadc1.Init.ContinuousConvMode = ENABLE; hadc1.Init.DiscontinuousConvMode = DISABLE; hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE; hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START; hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT; hadc1.Init.NbrOfConversion = 2; hadc1.Init.DMAContinuousRequests =ENABLE; hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV; if (HAL_ADC_Init(&hadc1) != HAL_OK) { Error_Handler(); } /**Configure for the selected ADC regular channel its corresponding rank in the sequencer and its sample time. */ sConfig.Channel = ADC_CHANNEL_1; sConfig.Rank = 1; sConfig.SamplingTime = ADC_SAMPLETIME_112CYCLES; if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK) { Error_Handler(); } /**Configure for the selected ADC regular channel its corresponding rank in the sequencer and its sample time. */ sConfig.Channel = ADC_CHANNEL_2; sConfig.Rank = 2; if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK) { Error_Handler(); }}void HAL_ADC_MspInit(ADC_HandleTypeDef* adcHandle){ GPIO_InitTypeDef GPIO_InitStruct; if(adcHandle->Instance==ADC1) { /* USER CODE BEGIN ADC1_MspInit 0 */ /* USER CODE END ADC1_MspInit 0 */ /* Peripheral clock enable */ __HAL_RCC_ADC1_CLK_ENABLE(); /**ADC1 GPIO Configuration PA1 ------> ADC1_IN1 PA2 ------> ADC1_IN2 */ GPIO_InitStruct.Pin = GPIO_PIN_1|GPIO_PIN_2; GPIO_InitStruct.Mode = GPIO_MODE_ANALOG; GPIO_InitStruct.Pull = GPIO_NOPULL; HAL_GPIO_Init(GPIOA, &GPIO_InitStruct); /* Peripheral DMA init*/ hdma_adc1.Instance = DMA2_Stream0; hdma_adc1.Init.Channel = DMA_CHANNEL_0; hdma_adc1.Init.Direction = DMA_PERIPH_TO_MEMORY; hdma_adc1.Init.PeriphInc = DMA_PINC_DISABLE; hdma_adc1.Init.MemInc = DMA_MINC_ENABLE; hdma_adc1.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD; hdma_adc1.Init.MemDataAlignment = DMA_MDATAALIGN_WORD; hdma_adc1.Init.Mode = DMA_CIRCULAR; hdma_adc1.Init.Priority = DMA_PRIORITY_HIGH; hdma_adc1.Init.FIFOMode = DMA_FIFOMODE_ENABLE; hdma_adc1.Init.FIFOThreshold = DMA_FIFO_THRESHOLD_FULL; if (HAL_DMA_Init(&hdma_adc1) != HAL_OK) { Error_Handler(); } __HAL_LINKDMA(adcHandle,DMA_Handle,hdma_adc1); /* USER CODE BEGIN ADC1_MspInit 1 */ /* USER CODE END ADC1_MspInit 1 */ }}#adc #dma #strange-points
Posted on April 22, 2017 at 20:32
I don't think that's the serial buffer because I set to see the variable in Coocox and press Run each time I want to see the new values in Debug mode, after that I copy and paste to importation. As you said, it seems to be a DMA Circular problem, because when I disable the DMA continuous request ( hadc1.Init.DMAContinuousRequests = DISABLE;) I got the correct signal wave, and I?m not getting it in the same position because I?m not sampling exactly one period.
However, I can?t update the buffer anymore.
That?s what I got when I changed the Length to 512 (hadc1.Init.DMAContinuousRequests = ENABLE;),
After Run again:
And with hadc1.Init.DMAContinuousRequests = DISABLE:
How can I check the DMA counter ? It?s always in 256 for Length = 256 and 512 forLength = 512;
