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CRC calculation gives 32 bit number instead of 8 bit

Adar70
Associate II

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 */
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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

1 ACCEPTED SOLUTION

Accepted Solutions

>>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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View solution in original post

1 REPLY 1

>>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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Up vote any posts that you find helpful, it shows what's working..