Hey. I am trying to read multiple ADC channels using DMA but with no luck. My project settings:
I have selected 4 channels and enabled Continuous conversion mode as well as DMA Continuous requests.
I have also created a circular DMA for ADC :
#include "main.h"
#include <errno.h>
#include <sys/unistd.h> // STDOUT_FILENO, STDERR_FILENO
ADC_HandleTypeDef hadc;
DMA_HandleTypeDef hdma_adc;
UART_HandleTypeDef huart1;
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_ADC_Init(void);
static void MX_DMA_Init(void);
static void MX_USART1_UART_Init(void);
int _write(int file, char *data, int len)
{
if ((file != STDOUT_FILENO) && (file != STDERR_FILENO))
{
errno = EBADF;
return -1;
}
// arbitrary timeout 1000
HAL_StatusTypeDef status =
HAL_UART_Transmit(&huart1, (uint8_t*)data, len, 1000);
// return # of bytes written - as best we can tell
return (status == HAL_OK ? len : 0);
}
uint16_t dma_buf[4];
int main(void)
{
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_ADC_Init();
MX_DMA_Init();
MX_USART1_UART_Init();
/* USER CODE BEGIN 2 */
HAL_ADC_Start_DMA(&hadc, dma_buf, 4);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
HAL_Delay(1000);
}
}
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB buses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
{
Error_Handler();
}
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USART1;
PeriphClkInit.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK2;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
{
Error_Handler();
}
}
/**
* @brief ADC Initialization Function
* @param None
* @retval None
*/
static void MX_ADC_Init(void)
{
/* USER CODE BEGIN ADC_Init 0 */
/* USER CODE END ADC_Init 0 */
ADC_ChannelConfTypeDef sConfig = {0};
/* USER CODE BEGIN ADC_Init 1 */
/* USER CODE END ADC_Init 1 */
/** Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion)
*/
hadc.Instance = ADC1;
hadc.Init.OversamplingMode = DISABLE;
hadc.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;
hadc.Init.Resolution = ADC_RESOLUTION_12B;
hadc.Init.SamplingTime = ADC_SAMPLETIME_1CYCLE_5;
hadc.Init.ScanConvMode = ADC_SCAN_DIRECTION_FORWARD;
hadc.Init.DataAlign = ADC_DATAALIGN_RIGHT;
hadc.Init.ContinuousConvMode = ENABLE;
hadc.Init.DiscontinuousConvMode = DISABLE;
hadc.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
hadc.Init.ExternalTrigConv = ADC_SOFTWARE_START;
hadc.Init.DMAContinuousRequests = ENABLE;
hadc.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
hadc.Init.Overrun = ADC_OVR_DATA_PRESERVED;
hadc.Init.LowPowerAutoWait = DISABLE;
hadc.Init.LowPowerFrequencyMode = DISABLE;
hadc.Init.LowPowerAutoPowerOff = DISABLE;
if (HAL_ADC_Init(&hadc) != HAL_OK)
{
Error_Handler();
}
/** Configure for the selected ADC regular channel to be converted.
*/
sConfig.Channel = ADC_CHANNEL_0;
sConfig.Rank = ADC_RANK_CHANNEL_NUMBER;
if (HAL_ADC_ConfigChannel(&hadc, &sConfig) != HAL_OK)
{
Error_Handler();
}
/** Configure for the selected ADC regular channel to be converted.
*/
sConfig.Channel = ADC_CHANNEL_1;
if (HAL_ADC_ConfigChannel(&hadc, &sConfig) != HAL_OK)
{
Error_Handler();
}
/** Configure for the selected ADC regular channel to be converted.
*/
sConfig.Channel = ADC_CHANNEL_2;
if (HAL_ADC_ConfigChannel(&hadc, &sConfig) != HAL_OK)
{
Error_Handler();
}
/** Configure for the selected ADC regular channel to be converted.
*/
sConfig.Channel = ADC_CHANNEL_3;
if (HAL_ADC_ConfigChannel(&hadc, &sConfig) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN ADC_Init 2 */
/* USER CODE END ADC_Init 2 */
}
/**
* @brief USART1 Initialization Function
* @param None
* @retval None
*/
static void MX_USART1_UART_Init(void)
{
/* USER CODE BEGIN USART1_Init 0 */
/* USER CODE END USART1_Init 0 */
/* USER CODE BEGIN USART1_Init 1 */
/* USER CODE END USART1_Init 1 */
huart1.Instance = USART1;
huart1.Init.BaudRate = 115200;
huart1.Init.WordLength = UART_WORDLENGTH_8B;
huart1.Init.StopBits = UART_STOPBITS_1;
huart1.Init.Parity = UART_PARITY_NONE;
huart1.Init.Mode = UART_MODE_TX_RX;
huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart1.Init.OverSampling = UART_OVERSAMPLING_16;
huart1.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
huart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
if (HAL_UART_Init(&huart1) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN USART1_Init 2 */
/* USER CODE END USART1_Init 2 */
}
/**
* Enable DMA controller clock
*/
static void MX_DMA_Init(void)
{
/* DMA controller clock enable */
__HAL_RCC_DMA1_CLK_ENABLE();
/* DMA interrupt init */
/* DMA1_Channel1_IRQn interrupt configuration */
HAL_NVIC_SetPriority(DMA1_Channel1_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(DMA1_Channel1_IRQn);
}
/**
* @brief GPIO Initialization Function
* @param None
* @retval None
*/
static void MX_GPIO_Init(void)
{
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOA_CLK_ENABLE();
}
/* USER CODE BEGIN 4 */
/* USER CODE END 4 */
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
__disable_irq();
while (1)
{
}
/* USER CODE END Error_Handler_Debug */
}
#ifdef USE_FULL_ASSERT
/**
* @brief Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* @param file: pointer to the source file name
* @param line: assert_param error line source number
* @retval None
*/
void assert_failed(uint8_t *file, uint32_t line)
{
/* USER CODE BEGIN 6 */
/* User can add his own implementation to report the file name and line number,
ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */As you can see I have created an array of size 4 for my DMA buffer:
uint16_t dma_buf[4];
and I start the DMA:
HAL_ADC_Start_DMA(&hadc, dma_buf, 4);
I set a breakpoint in while loop every 1 second and have added dma_buf to the expressions. Only the first element of an array is getting filled and it seems that it is a wrong value. I have about 2.9V on that pin so a reading should be about 3600 or 3500:
I have also attempted to try and read multiple channels using polling method instead of DMA.
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
HAL_ADC_Start(&hadc);
HAL_ADC_PollForConversion(&hadc, HAL_MAX_DELAY);
uint16_t adc_value1 = HAL_ADC_GetValue(&hadc);
//HAL_ADC_Start(&hadc);
HAL_ADC_PollForConversion(&hadc, HAL_MAX_DELAY);
uint16_t adc_value2 = HAL_ADC_GetValue(&hadc);
//HAL_ADC_Start(&hadc);
HAL_ADC_PollForConversion(&hadc, HAL_MAX_DELAY);
uint16_t adc_value3 = HAL_ADC_GetValue(&hadc);
//HAL_ADC_Start(&hadc);
HAL_ADC_PollForConversion(&hadc, HAL_MAX_DELAY);
uint16_t adc_value4 = HAL_ADC_GetValue(&hadc);
HAL_ADC_PollForConversion(&hadc, HAL_MAX_DELAY);
uint16_t adc_value5 = HAL_ADC_GetValue(&hadc);
//HAL_ADC_Start(&hadc);
HAL_ADC_PollForConversion(&hadc, HAL_MAX_DELAY);
uint16_t adc_value6 = HAL_ADC_GetValue(&hadc);
//HAL_ADC_Start(&hadc);
HAL_ADC_PollForConversion(&hadc, HAL_MAX_DELAY);
uint16_t adc_value7 = HAL_ADC_GetValue(&hadc);
//HAL_ADC_Start(&hadc);
HAL_ADC_PollForConversion(&hadc, HAL_MAX_DELAY);
uint16_t adc_value8 = HAL_ADC_GetValue(&hadc);
//HAL_ADC_Start(&hadc);
HAL_ADC_PollForConversion(&hadc, HAL_MAX_DELAY);
uint16_t adc_value9 = HAL_ADC_GetValue(&hadc);
//HAL_ADC_Start(&hadc);
HAL_ADC_PollForConversion(&hadc, HAL_MAX_DELAY);
uint16_t adc_value10 = HAL_ADC_GetValue(&hadc);
printf("adc_value 1 = %u \n",adc_value1);
printf("adc_value 2 = %u \n",adc_value2);
printf("adc_value 3 = %u \n",adc_value3);
printf("adc_value 4 = %u \n",adc_value4);
printf("adc_value 5 = %u \n",adc_value5);
printf("adc_value 6 = %u \n",adc_value6);
printf("adc_value 7 = %u \n",adc_value7);
printf("adc_value 8 = %u \n",adc_value8);
printf("adc_value 9 = %u \n",adc_value9);
printf("adc_value 10 = %u \n",adc_value10);
printf("\n");
HAL_ADC_Stop(&hadc);
HAL_Delay(1000);
}I am getting the strangest results, when ADC0 is shorted to ground(adc_value 5 changed)
adc_value 1 = 3554
adc_value 2 = 3486
adc_value 3 = 3602
adc_value 4 = 3605
adc_value 5 = 66
adc_value 6 = 3520
adc_value 7 = 3560
adc_value 8 = 3486
adc_value 9 = 3521
adc_value 10 = 3606
when ADC1 is shorted to ground, none of the values change
adc_value 1 = 3546
adc_value 2 = 3462
adc_value 3 = 3394
adc_value 4 = 3462
adc_value 5 = 3594
adc_value 6 = 3523
adc_value 7 = 3560
adc_value 8 = 3462
adc_value 9 = 3504
adc_value 10 = 66
when ADC2 is shorted to ground (adc value4 and ac value10 are changed):
adc_value 1 = 3550
adc_value 2 = 3469
adc_value 3 = 3397
adc_value 4 = 66
adc_value 5 = 3600
adc_value 6 = 3524
adc_value 7 = 3561
adc_value 8 = 3469
adc_value 9 = 3510
adc_value 10 = 66
When ADC3 is shorted to ground adc value 3 change
adc_value 1 = 3543
adc_value 2 = 3462
adc_value 3 = 66
adc_value 4 = 3610
adc_value 5 = 3604
adc_value 6 = 3528
adc_value 7 = 3564
adc_value 8 = 3461
adc_value 9 = 3291
adc_value 10 = 3612
when ADC4 is shorted to ground, adc_value 9 change:
adc_value 1 = 3533
adc_value 2 = 3200
adc_value 3 = 3602
adc_value 4 = 3609
adc_value 5 = 3605
adc_value 6 = 3524
adc_value 7 = 3557
adc_value 8 = 3200
adc_value 9 = 66
adc_value 10 = 3610
when ADC5 is shorted to ground adc value 2 and and value 8 change:
adc_value 1 = 3316
adc_value 2 = 68
adc_value 3 = 3608
adc_value 4 = 3616
adc_value 5 = 3611
adc_value 6 = 3523
adc_value 7 = 3554
adc_value 8 = 66
adc_value 9 = 3534
adc_value 10 = 3616
when ADC6 is shorted to ground, adc_value 1 is changed:
adc_value 1 = 66
adc_value 2 = 3484
adc_value 3 = 3607
adc_value 4 = 3610
adc_value 5 = 3606
adc_value 6 = 3508
adc_value 7 = 3308
adc_value 8 = 3484
adc_value 9 = 3530
adc_value 10 = 3612
and etc.... As you can see, it is messed up. Could someone help me understand why would that happen?
