UART loop in STM32H753

[Naresh_]

Hi 

  i am receive data using UART 4 and transfer same data back like loopback but data is mismatch.
  same process in stm32f207 is working, 

#include "main.h"

UART_HandleTypeDef huart4;

void SystemClock_Config(void);

static void MX_GPIO_Init(void);

static void MX_UART4_Init(void);

int main(void)

{

char rx_buffer[10]={0};

HAL_Init();

SystemClock_Config();

MX_GPIO_Init();

MX_UART4_Init();

while (1)

{

HAL_UART_Receive(&huart4, rx_buffer, 10, 1000);

HAL_Delay(100);

HAL_UART_Transmit(&huart4, rx_buffer, 10, 100);

// HAL_Delay(1000);

}

/* USER CODE END 3 */

}



void SystemClock_Config(void)

{

RCC_OscInitTypeDef RCC_OscInitStruct = {0};

RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};



/** Supply configuration update enable

*/

HAL_PWREx_ConfigSupply(PWR_LDO_SUPPLY);



/** Configure the main internal regulator output voltage

*/

__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE2);



while(!__HAL_PWR_GET_FLAG(PWR_FLAG_VOSRDY)) {}



/** 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_DIV1;

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_CLOCKTYPE_D3PCLK1|RCC_CLOCKTYPE_D1PCLK1;

RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;

RCC_ClkInitStruct.SYSCLKDivider = RCC_SYSCLK_DIV1;

RCC_ClkInitStruct.AHBCLKDivider = RCC_HCLK_DIV1;

RCC_ClkInitStruct.APB3CLKDivider = RCC_APB3_DIV1;

RCC_ClkInitStruct.APB1CLKDivider = RCC_APB1_DIV1;

RCC_ClkInitStruct.APB2CLKDivider = RCC_APB2_DIV1;

RCC_ClkInitStruct.APB4CLKDivider = RCC_APB4_DIV1;



if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK)

{

Error_Handler();

}

}



static void MX_UART4_Init(void)

{

/* USER CODE END UART4_Init 1 */

huart4.Instance = UART4;

huart4.Init.BaudRate = 115200;

huart4.Init.WordLength = UART_WORDLENGTH_8B;

huart4.Init.StopBits = UART_STOPBITS_1;

huart4.Init.Parity = UART_PARITY_NONE;

huart4.Init.Mode = UART_MODE_TX_RX;

huart4.Init.HwFlowCtl = UART_HWCONTROL_NONE;

huart4.Init.OverSampling = UART_OVERSAMPLING_16;

huart4.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;

huart4.Init.ClockPrescaler = UART_PRESCALER_DIV1;

huart4.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;

if (HAL_UART_Init(&huart4) != HAL_OK)

{

Error_Handler();

}

if (HAL_UARTEx_SetTxFifoThreshold(&huart4, UART_TXFIFO_THRESHOLD_1_8) != HAL_OK)

{

Error_Handler();

}

if (HAL_UARTEx_SetRxFifoThreshold(&huart4, UART_RXFIFO_THRESHOLD_1_8) != HAL_OK)

{

Error_Handler();

}

if (HAL_UARTEx_DisableFifoMode(&huart4) != HAL_OK)

{

Error_Handler();

}

}



static void MX_GPIO_Init(void)

{



/* GPIO Ports Clock Enable */

__HAL_RCC_GPIOC_CLK_ENABLE();

__HAL_RCC_GPIOH_CLK_ENABLE();

__HAL_RCC_GPIOA_CLK_ENABLE();



/* USER CODE BEGIN MX_GPIO_Init_2 */

/* USER CODE END MX_GPIO_Init_2 */

}

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 */

}

[SofLit]

Hello,

Please use the button </> to insert your code.

Please read these recommendations on how to post a thread: https://community.st.com/t5/community-guidelines/how-to-write-your-question-to-maximize-your-chances-to-find-a/ta-p/575228

Thank you for your understanding

[PPopo.1]

try resetting the buffer after transfer, also why different delays?

If full data is not received than it wont be sent as expected. Use a debugger to check if you receive what you are expecting.

[Naresh_]

Hi 

      This is working in custom board but it's not working EVK board, what is issue?

Thank you 

[SofLit]

Hello,

---

@Naresh_ wrote:

      This is working in custom board but it's not working EVK board, what is issue?

---

Need to check your hardware differences on both boards: what is connected externally on UART4 pins apart of your looping-back wire?

[Naresh_]

Hi SofLit,

thank you quick response, 

yes loop back is also requirement, but in receive side some data+ ACK is also loop back.

[SofLit]

What do you mean by "ACK"?

Again check your HW and the differences between the boards on UART4_TX and UART4_RX pins

[Andrew Neil · Accepted solution]

---

@Naresh_ wrote:

I am receive data using UART 4 and transfer same data back like loopback but data is mismatch.

The commonest reason for receiving "junk" characters is wrong baud rate:

https://learn.sparkfun.com/tutorials/serial-communication/all#:~:text=If%20all%20the%20receiving%20device%20sees%20on%20its%20receive%20line%20is%20garbage%2C%20check%20to%20make%20sure%20the%20baud%20rates%20match%20up.

Baud rate depends on your clock setup - so check that.

Use the debugger to check if the corruption happens on reception or transmission - or both!

---

@Naresh_ wrote:

 same process in stm32f207 is working, 

So look carefully at the differences between those two systems.

Again, use the debugger to see what is happening in the stm32f207, and compare/contrast what is happening in the STM32H753 ...