How can i send integer or float values using UART in DMA mode, Model:STM32H745XI-DISCO Board, i dont know why but this is not working...

[Vijay Krishna]

/* USER CODE BEGIN Header */

/**

 ******************************************************************************

 * @file      : main.c

 * @brief     : Main program body

 ******************************************************************************

 * @attention

 *

 * Copyright (c) 2022 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 "adc.h"

#include "dma.h"

#include "usart.h"

#include "gpio.h"

/* Private includes ----------------------------------------------------------*/

/* USER CODE BEGIN Includes */

#include<stdio.h>

#include<string.h>

#include <stdlib.h>

/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/

/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/

/* USER CODE BEGIN PD */

#ifndef HSEM_ID_0

#define HSEM_ID_0 (0U) /* HW semaphore 0*/

#endif

/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/

/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/

/* USER CODE BEGIN PV */

uint8_t buffer[256];

uint8_t num2=2;

uint16_t u, len;

//uint8_t zz;

//char str[32];

volatile int i, l;

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/

void SystemClock_Config(void);

/* USER CODE BEGIN PFP */

void myDelay(int num1)

{

volatile int ii, j;

for (ii=0;ii<num1;++ii);

j++;

}

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/

/* USER CODE BEGIN 0 */

int _write(int fd, char* ptr, int len) {

HAL_UART_Transmit(&huart1, (uint8_t *) ptr, len, HAL_MAX_DELAY);

return len;

}

void HAL_UART_TxHalfCpltCallback(UART_HandleTypeDef *huart)

{

HAL_GPIO_TogglePin(GPIOJ,GPIO_PIN_2);

myDelay(10000000);

}

void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart)

{

HAL_UART_Transmit_DMA(&huart1, buffer, len);

}

/* USER CODE END 0 */

/**

 * @brief The application entry point.

 * @retval int

 */

int main(void)

{

 /* USER CODE BEGIN 1 */

 /* USER CODE END 1 */

/* USER CODE BEGIN Boot_Mode_Sequence_0 */

 //int32_t timeout;

/* USER CODE END Boot_Mode_Sequence_0 */

 /* Enable I-Cache---------------------------------------------------------*/

 SCB_EnableICache();

 /* Enable D-Cache---------------------------------------------------------*/

 SCB_EnableDCache();

/* USER CODE BEGIN Boot_Mode_Sequence_1 */

 /* Wait until CPU2 boots and enters in stop mode or timeout*/

/* USER CODE END Boot_Mode_Sequence_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 Boot_Mode_Sequence_2 */

/* When system initialization is finished, Cortex-M7 will release Cortex-M4 by means of

HSEM notification */

/*HW semaphore Clock enable*/

__HAL_RCC_HSEM_CLK_ENABLE();

/*Take HSEM */

/* USER CODE END Boot_Mode_Sequence_2 */

 /* USER CODE BEGIN SysInit */

 /* USER CODE END SysInit */

 /* Initialize all configured peripherals */

 MX_GPIO_Init();

 MX_DMA_Init();

 MX_USART1_UART_Init();

 MX_ADC1_Init();

 /* USER CODE BEGIN 2 */

 for (u=0;u<256;u++) buffer[u]=u;

 len=sizeof(buffer);

 HAL_UART_Transmit_DMA(&huart1, buffer, len);

    // printf("%d\n",student[i]);

 /* USER CODE END 2 */

 /* Infinite loop */

 /* USER CODE BEGIN WHILE */

 //HAL_UART_Transmit_DMA(&huart1,temp,((strlen(temp))-1));

 while (1)

 {

  /* USER CODE END WHILE */

  /* USER CODE BEGIN 3 */

 }

 /* USER CODE END 3 */

}

/**

 * @brief System Clock Configuration

 * @retval None

 */

void SystemClock_Config(void)

{

 RCC_OscInitTypeDef RCC_OscInitStruct = {0};

 RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

 /** Supply configuration update enable

 */

 HAL_PWREx_ConfigSupply(PWR_DIRECT_SMPS_SUPPLY);

 /** Configure the main internal regulator output voltage

 */

 __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

 while(!__HAL_PWR_GET_FLAG(PWR_FLAG_VOSRDY)) {}

 /** Macro to configure the PLL clock source

 */

 __HAL_RCC_PLL_PLLSOURCE_CONFIG(RCC_PLLSOURCE_HSE);

 /** Initializes the RCC Oscillators according to the specified parameters

 * in the RCC_OscInitTypeDef structure.

 */

 RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;

 RCC_OscInitStruct.HSEState = RCC_HSE_ON;

 RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;

 RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;

 RCC_OscInitStruct.PLL.PLLM = 5;

 RCC_OscInitStruct.PLL.PLLN = 160;

 RCC_OscInitStruct.PLL.PLLP = 2;

 RCC_OscInitStruct.PLL.PLLQ = 4;

 RCC_OscInitStruct.PLL.PLLR = 4;

 RCC_OscInitStruct.PLL.PLLRGE = RCC_PLL1VCIRANGE_2;

 RCC_OscInitStruct.PLL.PLLVCOSEL = RCC_PLL1VCOWIDE;

 RCC_OscInitStruct.PLL.PLLFRACN = 0;

 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_CLOCKTYPE_D3PCLK1|RCC_CLOCKTYPE_D1PCLK1;

 RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;

 RCC_ClkInitStruct.SYSCLKDivider = RCC_SYSCLK_DIV1;

 RCC_ClkInitStruct.AHBCLKDivider = RCC_HCLK_DIV2;

 RCC_ClkInitStruct.APB3CLKDivider = RCC_APB3_DIV2;

 RCC_ClkInitStruct.APB1CLKDivider = RCC_APB1_DIV2;

 RCC_ClkInitStruct.APB2CLKDivider = RCC_APB2_DIV2;

 RCC_ClkInitStruct.APB4CLKDivider = RCC_APB4_DIV2;

 if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != 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 */

[TDK]

> Model:STM32H745XI

> SCB_EnableDCache();

> HAL_UART_Transmit_DMA(&huart1, buffer, len);

Almost certainly a cache issue (and perhaps other things as well).

https://community.st.com/s/article/FAQ-DMA-is-not-working-on-STM32H7-devices

Get blocking mode to work first, then graduate to DMA mode.

[Tesla DeLorean]

It sends a block of bytes. These span codes outside the ASCII printable range, and aren't human readable

If you send float or double variables each of these will be 4 or 8 bytes respectively, and encoded in a form consistent with IEEE-754, unfamiliar with the topic of "Data Representation", perhaps review that first.

They will be received in the encoded forms, so the receiving application should expect that.

For Human-Readable numeric representation, as ASCII characters you'll need to use conversions.

In full C implementations you could use %f, %lf, %e or %le type formats in sprintf(), or use primitives like dtoa(), or for integers itoa()

HAL_UART_Transmit(&huart1, buffer, sprintf(buffer, "%lf\n", 123.45), 1000);