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Associate II
May 27, 2024
Solved

CRC calculation gives 32 bit number instead of 8 bit

  • May 27, 2024
  • 1 reply
  • 1123 views

Hello. I'm trying to obtain CRC value from CRC peripheral. It's supposed to give me 8 bit number. Instead it gives me 32 bit number. What am I doing wrong? Below is the code and program outputs.

 

/* 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"

/* 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 ---------------------------------------------------------*/
CRC_HandleTypeDef hcrc;

UART_HandleTypeDef huart2;

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART2_UART_Init(void);
static void MX_CRC_Init(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_USART2_UART_Init();
 MX_CRC_Init();
 /* USER CODE BEGIN 2 */

 uint8_t uart_buffer[4] = {0};
 uint32_t crc_input_arr[1];
 uint32_t crc_out = 0;

 /* USER CODE END 2 */

 /* Infinite loop */
 /* USER CODE BEGIN WHILE */
 while (1)
 {
 /* USER CODE END WHILE */

 /* USER CODE BEGIN 3 */
	HAL_UART_Receive(&huart2, uart_buffer, 4, HAL_MAX_DELAY);
	crc_input_arr[0] = \
	 (((uint32_t) uart_buffer[0]) << 24) | \
	 (((uint32_t) uart_buffer[1]) << 16) | \
	 (((uint32_t) uart_buffer[2]) << 8) | \
	 (((uint32_t) uart_buffer[3]));
	crc_out = HAL_CRC_Calculate(&hcrc, crc_input_arr, 4);
	HAL_UART_Transmit(&huart2, (uint8_t *)crc_out, 4, HAL_MAX_DELAY);
 }
 /* USER CODE END 3 */
}

/**
 * @brief System Clock Configuration
 * @retval None
 */
void SystemClock_Config(void)
{
 RCC_OscInitTypeDef RCC_OscInitStruct = {0};
 RCC_ClkInitTypeDef RCC_ClkInitStruct = {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_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();
 }
}

/**
 * @brief CRC Initialization Function
 * @PAram None
 * @retval None
 */
static void MX_CRC_Init(void)
{

 /* USER CODE BEGIN CRC_Init 0 */

 /* USER CODE END CRC_Init 0 */

 /* USER CODE BEGIN CRC_Init 1 */

 /* USER CODE END CRC_Init 1 */
 hcrc.Instance = CRC;
 hcrc.Init.DefaultPolynomialUse = DEFAULT_POLYNOMIAL_DISABLE;
 hcrc.Init.DefaultInitValueUse = DEFAULT_INIT_VALUE_DISABLE;
 hcrc.Init.GeneratingPolynomial = 7;
 hcrc.Init.CRCLength = CRC_POLYLENGTH_8B;
 hcrc.Init.InitValue = 0;
 hcrc.Init.InputDataInversionMode = CRC_INPUTDATA_INVERSION_BYTE;
 hcrc.Init.OutputDataInversionMode = CRC_OUTPUTDATA_INVERSION_DISABLE;
 hcrc.InputDataFormat = CRC_INPUTDATA_FORMAT_BYTES;
 if (HAL_CRC_Init(&hcrc) != HAL_OK)
 {
 Error_Handler();
 }
 /* USER CODE BEGIN CRC_Init 2 */

 /* USER CODE END CRC_Init 2 */

}

/**
 * @brief USART2 Initialization Function
 * @PAram None
 * @retval None
 */
static void MX_USART2_UART_Init(void)
{

 /* USER CODE BEGIN USART2_Init 0 */

 /* USER CODE END USART2_Init 0 */

 /* USER CODE BEGIN USART2_Init 1 */

 /* USER CODE END USART2_Init 1 */
 huart2.Instance = USART2;
 huart2.Init.BaudRate = 38400;
 huart2.Init.WordLength = UART_WORDLENGTH_8B;
 huart2.Init.StopBits = UART_STOPBITS_1;
 huart2.Init.Parity = UART_PARITY_NONE;
 huart2.Init.Mode = UART_MODE_TX_RX;
 huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
 huart2.Init.OverSampling = UART_OVERSAMPLING_16;
 huart2.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
 huart2.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_RXOVERRUNDISABLE_INIT;
 huart2.AdvancedInit.OverrunDisable = UART_ADVFEATURE_OVERRUN_DISABLE;
 if (HAL_UART_Init(&huart2) != HAL_OK)
 {
 Error_Handler();
 }
 /* USER CODE BEGIN USART2_Init 2 */

 /* USER CODE END USART2_Init 2 */

}

/**
 * @brief GPIO Initialization Function
 * @PAram None
 * @retval None
 */
static void MX_GPIO_Init(void)
{
 GPIO_InitTypeDef GPIO_InitStruct = {0};
/* USER CODE BEGIN MX_GPIO_Init_1 */
/* USER CODE END MX_GPIO_Init_1 */

 /* GPIO Ports Clock Enable */
 __HAL_RCC_GPIOA_CLK_ENABLE();
 __HAL_RCC_GPIOB_CLK_ENABLE();

 /*Configure GPIO pin Output Level */
 HAL_GPIO_WritePin(LED3_GPIO_Port, LED3_Pin, GPIO_PIN_RESET);

 /*Configure GPIO pin : LED3_Pin */
 GPIO_InitStruct.Pin = LED3_Pin;
 GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
 GPIO_InitStruct.Pull = GPIO_NOPULL;
 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
 HAL_GPIO_Init(LED3_GPIO_Port, &GPIO_InitStruct);

/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}

/* 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 */

 

The outputs (spaces added for readability):

inp.: 0x05 00 00 00, outp.: 0x05 00 08 dd
0x11 11 11 11, 0xdd 05 00 08
0x11 22 33 44, 0x00 31 05 00

This topic has been closed for replies.
Best answer by Tesla DeLorean

>>What am I doing wrong? Below is the code and program outputs

What's the test vector / expectation of values returned here?

	crc_out = HAL_CRC_Calculate(&hcrc, crc_input_arr, 4);
	HAL_UART_Transmit(&huart2, (uint8_t *)crc_out, 4, HAL_MAX_DELAY);

crc_out is a 32-bit variable, it needs to be a pointer and address for the HAL_UART_Transmit() function.

You've got a blind cast of the wrong type. would need to be (uint8_t *)&crc_out

 

1 reply

Tesla DeLorean
Tesla DeLoreanBest answer
Guru
May 27, 2024

>>What am I doing wrong? Below is the code and program outputs

What's the test vector / expectation of values returned here?

	crc_out = HAL_CRC_Calculate(&hcrc, crc_input_arr, 4);
	HAL_UART_Transmit(&huart2, (uint8_t *)crc_out, 4, HAL_MAX_DELAY);

crc_out is a 32-bit variable, it needs to be a pointer and address for the HAL_UART_Transmit() function.

You've got a blind cast of the wrong type. would need to be (uint8_t *)&crc_out

 

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