stm32u585 UART receive not working, transmit working

[_Danny_]

Hi
I have been using stm32u585QII3 MCU in our custom board. I am using USART1(PB6, PG10) to transmit and receive data. In interrupt mode transmit call back is working but receive call back was not working. Initially i have set a break point, the interrupt hits one time in debug mode, then when i try to send data, the interrupt is not hitting. I have tried this in polling method too, and it was not working. I have attached scope images of both  transmit and receive. In which the signals is being transmitted but not received by the controller. 

TRANSMITRECEIVE

[TDK]

> In interrupt mode transmit call back is working but receive call back was not working.

Debug your code, after you think it should have received data, hit pause and examine the state of the uart receive state machine and also the UART registers. Possibly it has errors.

> Initially i have set a break point, the interrupt hits one time in debug mode, then when i try to send data, the interrupt is not hitting.

Where exactly is the breakpoint? When it "hits one time" what is happening in the program and on the bus?

 

Looks like your TX signal goes to something external and that something external sends a signal back on RX. Correct?

[_Danny_]

Hi @TDK 
I have paused and examined the UART registers, there are no errors. The debug pointer comes out of the UART function and when i paused it is in the while function.

[Karl Yamashita]

---

@_Danny_ wrote:

Hi @TDK 
I have paused and examined the UART registers, there are no errors. The debug pointer comes out of the UART function and when i paused it is in the while function.

---

HAL drivers clear any register error flags. You'll have to check the UART instance as it saves the errors there.

See if this callback is called HAL_UART_ErrorCallback and if so you can check huart->ErrorCode

 

Looking at your waveform which doesn't look clean, maybe you have a noise error or framing error? Or did you not ground your probe?

 

[Karl Yamashita]

Show some code. Maybe you're not initializing the interrupt again after the first interrupt? 

[_Danny_]

Hi @Karl Yamashita 
I have attached the code for your reference. 


/* USER CODE BEGIN Header */

/**

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

  * @file           : main.c

  * @brief          : Main program body

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

  * @attention

  *

  * Copyright (c) 2024 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 "tim.h"

#include "usart.h"

#include "gpio.h"

 

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

/* USER CODE BEGIN Includes */

#include "string.h"

/* 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 rxbuffer[4];

 

/* 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_USART1_UART_Init();

  MX_TIM1_Init();

  /* USER CODE BEGIN 2 */

  HAL_UART_Receive_IT(&huart1, rxbuffer, sizeof(rxbuffer));

 

  /* USER CODE END 2 */

 

  /* Infinite loop */

  /* USER CODE BEGIN WHILE */

  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};

 

  /** Configure the main internal regulator output voltage

  */

  if (HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1) != HAL_OK)

  {

    Error_Handler();

  }

 

  /** Initializes the CPU, AHB and APB buses clocks

  */

  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.PLLMBOOST = RCC_PLLMBOOST_DIV1;

  RCC_OscInitStruct.PLL.PLLM = 3;

  RCC_OscInitStruct.PLL.PLLN = 30;

  RCC_OscInitStruct.PLL.PLLP = 2;

  RCC_OscInitStruct.PLL.PLLQ = 2;

  RCC_OscInitStruct.PLL.PLLR = 1;

  RCC_OscInitStruct.PLL.PLLRGE = RCC_PLLVCIRANGE_0;

  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_PCLK3;

  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;

  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;

  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;

  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  RCC_ClkInitStruct.APB3CLKDivider = RCC_HCLK_DIV1;

 

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_4) != HAL_OK)

  {

    Error_Handler();

  }

}

 

/* USER CODE BEGIN 4 */

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart){

  HAL_UART_Receive_IT(&huart1, rxbuffer, sizeof(rxbuffer));

}

 

/* 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 */