UART interrupt mode is working but HAL_UART_Transmit_DMA not work why?

[parth kothiya]

I want to send and receive data using DMA but HAL_UART_Transmit_DMA this function not sending any data returns HAL_BUSY error.

while uart in interrupt mode both send & receive data works fine.

how can i send data using DMA ?

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2021 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "dma.h"
#include "i2c.h"
#include "tim.h"
#include "usart.h"
#include "gpio.h"
 
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
 
/* USER CODE END Includes */
 
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
 
/* USER CODE END PTD */
 
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
/* USER CODE END PD */
 
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
 
/* USER CODE END PM */
 
/* Private variables ---------------------------------------------------------*/
 
/* USER CODE BEGIN PV */
uint8_t tx_buffer[20] = {0};
extern DMA_HandleTypeDef hdma_usart1_tx;
/* USER CODE END PV */
 
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */
 
/* USER CODE END PFP */
 
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
 
/* USER CODE END 0 */
 
/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{
  /* USER CODE BEGIN 1 */
 
  /* USER CODE END 1 */
 
  /* MCU Configuration--------------------------------------------------------*/
 
  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();
 
  /* USER CODE BEGIN Init */
 
  /* USER CODE END Init */
 
  /* Configure the system clock */
  SystemClock_Config();
 
  /* USER CODE BEGIN SysInit */
 
  /* USER CODE END SysInit */
 
  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_TIM3_Init();
  MX_USART1_UART_Init();
  MX_USART2_UART_Init();
  MX_DMA_Init();
  MX_I2C2_Init();
  /* USER CODE BEGIN 2 */
  for (uint8_t n = 0; n < 20; ++n) {
	tx_buffer[n] = n;
}
  /* USER CODE END 2 */
 
  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */
 
    /* USER CODE BEGIN 3 */
	  HAL_GPIO_WritePin(DR_ENABLE_GPIO_Port,DR_ENABLE_Pin,GPIO_PIN_SET);
	  		if (HAL_UART_Transmit_DMA(&huart1, tx_buffer, 20) == HAL_OK) {
	  			HAL_GPIO_WritePin(DR_ENABLE_GPIO_Port,DR_ENABLE_Pin,GPIO_PIN_RESET);
	  			HAL_GPIO_TogglePin(ERROR_LED_GPIO_Port, ERROR_LED_Pin);
	  		}
	  		if(HAL_GPIO_ReadPin(X0_GPIO_Port, X0_Pin) == GPIO_PIN_SET){
	  			HAL_GPIO_WritePin(Y0_GPIO_Port, Y0_Pin, GPIO_PIN_SET);
	  		}else {
	  			HAL_GPIO_WritePin(Y0_GPIO_Port, Y0_Pin, GPIO_PIN_RESET);
	  		}
 
	  		if (HAL_GPIO_ReadPin(X1_GPIO_Port, X1_Pin) == GPIO_PIN_SET) {
	  			HAL_GPIO_WritePin(Y1_GPIO_Port, Y1_Pin,GPIO_PIN_SET);
	  		} else {
	  			HAL_GPIO_WritePin(Y1_GPIO_Port, Y1_Pin,GPIO_PIN_RESET);
	  		}
 
	  		if (HAL_GPIO_ReadPin(X2_GPIO_Port, X2_Pin) == GPIO_PIN_SET) {
	  			HAL_GPIO_WritePin(Y2_GPIO_Port, Y2_Pin,GPIO_PIN_SET);
	  		} else {
	  			HAL_GPIO_WritePin(Y2_GPIO_Port, Y2_Pin,GPIO_PIN_RESET);
	  		}
	  		if (HAL_GPIO_ReadPin(X3_GPIO_Port, X3_Pin) == GPIO_PIN_SET) {
	  			HAL_GPIO_WritePin(Y3_GPIO_Port, Y3_Pin,GPIO_PIN_SET);
	  		} else {
	  			HAL_GPIO_WritePin(Y3_GPIO_Port, Y3_Pin,GPIO_PIN_RESET);
	  		}
	  		if (HAL_GPIO_ReadPin(X4_GPIO_Port, X4_Pin) == GPIO_PIN_SET) {
	  			HAL_GPIO_WritePin(Y4_GPIO_Port, Y4_Pin,GPIO_PIN_SET);
	  		} else {
	  			HAL_GPIO_WritePin(Y4_GPIO_Port, Y4_Pin,GPIO_PIN_RESET);
	  		}
	  		if (HAL_GPIO_ReadPin(X5_GPIO_Port, X5_Pin) == GPIO_PIN_SET) {
	  			HAL_GPIO_WritePin(Y5_GPIO_Port, Y5_Pin,GPIO_PIN_SET);
	  		} else {
	  			HAL_GPIO_WritePin(Y5_GPIO_Port, Y5_Pin,GPIO_PIN_RESET);
	  		}
	  		if (HAL_GPIO_ReadPin(X6_GPIO_Port, X6_Pin) == GPIO_PIN_SET) {
	  			HAL_GPIO_WritePin(Y6_GPIO_Port, Y6_Pin,GPIO_PIN_SET);
	  		} else {
	  			HAL_GPIO_WritePin(Y6_GPIO_Port, Y6_Pin,GPIO_PIN_RESET);
	  		}
	  		if (HAL_GPIO_ReadPin(X7_GPIO_Port, X7_Pin) == GPIO_PIN_SET) {
	  			HAL_GPIO_WritePin(Y7_GPIO_Port, Y7_Pin,GPIO_PIN_SET);
	  		} else {
	  			HAL_GPIO_WritePin(Y7_GPIO_Port, Y7_Pin,GPIO_PIN_RESET);
	  		}
	  		if (HAL_GPIO_ReadPin(X8_GPIO_Port, X8_Pin) == GPIO_PIN_SET) {
	  			HAL_GPIO_WritePin(Y1_GPIO_Port, Y1_Pin,GPIO_PIN_SET);
	  		} else {
	  			HAL_GPIO_WritePin(Y1_GPIO_Port, Y1_Pin,GPIO_PIN_RESET);
	  		}
	  		if (HAL_GPIO_ReadPin(X9_GPIO_Port, X9_Pin) == GPIO_PIN_SET) {
	  			HAL_GPIO_WritePin(Y1_GPIO_Port, Y1_Pin,GPIO_PIN_SET);
	  		} else {
	  			HAL_GPIO_WritePin(Y1_GPIO_Port, Y1_Pin,GPIO_PIN_RESET);
	  		}
	  		if (HAL_GPIO_ReadPin(X10_GPIO_Port, X10_Pin) == GPIO_PIN_SET) {
	  			HAL_GPIO_WritePin(Y1_GPIO_Port, Y1_Pin,GPIO_PIN_SET);
	  		} else {
	  			HAL_GPIO_WritePin(Y1_GPIO_Port, Y1_Pin,GPIO_PIN_RESET);
	  		}
	  		if (HAL_GPIO_ReadPin(X11_GPIO_Port, X11_Pin) == GPIO_PIN_SET) {
	  			HAL_GPIO_WritePin(Y1_GPIO_Port, Y1_Pin,GPIO_PIN_SET);
	  		} else {
	  			HAL_GPIO_WritePin(Y1_GPIO_Port, Y1_Pin,GPIO_PIN_RESET);
	  		}
	  		if (HAL_GPIO_ReadPin(X12_GPIO_Port, X12_Pin) == GPIO_PIN_SET) {
	  			HAL_GPIO_WritePin(Y1_GPIO_Port, Y1_Pin,GPIO_PIN_SET);
	  		} else {
	  			HAL_GPIO_WritePin(Y1_GPIO_Port, Y1_Pin,GPIO_PIN_RESET);
	  		}
	  		if (HAL_GPIO_ReadPin(X13_GPIO_Port, X13_Pin) == GPIO_PIN_SET) {
	  			HAL_GPIO_WritePin(Y1_GPIO_Port, Y1_Pin,GPIO_PIN_SET);
	  		} else {
	  			HAL_GPIO_WritePin(Y1_GPIO_Port, Y1_Pin,GPIO_PIN_RESET);
	  		}
 
  }
  /* USER CODE END 3 */
}
 
/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
  RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
 
  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL12;
  RCC_OscInitStruct.PLL.PREDIV = RCC_PREDIV_DIV1;
  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_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
 
  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK)
  {
    Error_Handler();
  }
  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USART1;
  PeriphClkInit.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK1;
  if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
  {
    Error_Handler();
  }
}
 
/* 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 */
 

[MM..1]

Try reorder

  MX_DMA_Init();
  MX_USART1_UART_Init();
  MX_USART2_UART_Init();

[TDK · Accepted solution]

https://community.st.com/s/question/0D53W00001EzCmCSAV/mxdmainit-order-in-the-mainc-file-generated-by-stm32cubemx-how-to-fix

[parth kothiya]

By changing initialisation of functions order my problem solve

​I'm continue sending data using DMA 1st time I received HAL_OK then few times getting busy then again received HAL_OK

Sends data in while loop without any delay​

So what is the proper way to sending data using DMA?​

[parth kothiya]

Thanks it's working

But till some time I get​ halbusy

So what is proper way to sending data using DMA?

I'm sending data in while loop.

I need to check any flag defore sending new data​?

[parth kothiya]

Thanks it's working

But till some time I get​ halbusy

So what is proper way to sending data using DMA?

I'm sending data in while loop.

I need to check any flag defore sending new data​?

[parth kothiya]

Thanks it's working

But till some time I get​ halbusy

So what is proper way to sending data using DMA?

I'm sending data in while loop.

I need to check any flag defore sending new data​?

[TDK]

DMA operations are not instantaneous. You need to wait for the first operation to complete before starting a new one. Wait for the state member variable to be ready.

[parth kothiya]

I simply put 20ms delay after sending data then it works fine.

but if i continuously check uart status till ready then its not working I'm using FREE RTOS

if (HAL_UART_Transmit_DMA(&MB_Port, Tx_buf, 8) == HAL_OK) {
 
	}
	HAL_GPIO_WritePin(ERROR_LED_GPIO_Port, ERROR_LED_Pin, GPIO_PIN_SET);
	while(HAL_UART_GetState(&huart1) != HAL_UART_STATE_READY){
		HAL_Delay(1);
	}

how can i solve it without using delay function

put uart in ready mode in interrupt after tx_complete callback it solve my problem?

any other solution?

[MM..1]

Seems you dont understand DMA , then dont use it.

But little explain DMA is for offload MCU, DMA is standalone controller, you programm it and leave do his job.

Your code continue and do other jobs here.

Before next send need check and wait for end last send. You need ask DMA or use DMA transfer complete IRQ , that marks your code flag as done.