The CRC_Accumulate() function has been called in while loop and the rx_data received as uint8_t and converted into uint32_t and then passed to CRC_accumulate() function in order to calculate the CRC value, but unfortunately the CRC value changes every cycle, what should I do to correct this behaviour?
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "fatfs.h"
#include "usb_device.h"
/* Private define ------------------------------------------------------------*/
#define RX_BUFFER_SIZE 20
#define BUFFER_SIZE 5U
/* Private variables ---------------------------------------------------------*/
ADC_HandleTypeDef hadc;
CRC_HandleTypeDef hcrc;
I2C_HandleTypeDef hi2c1;
RTC_HandleTypeDef hrtc;
SPI_HandleTypeDef hspi1;
TIM_HandleTypeDef htim2;
TIM_HandleTypeDef htim3;
TIM_HandleTypeDef htim5;
TIM_HandleTypeDef htim9;
UART_HandleTypeDef huart1;
DMA_HandleTypeDef hdma_usart1_rx;
/* USER CODE BEGIN PV */
uint8_t rx_buffer[RX_BUFFER_SIZE], rx_flag, rx_index, rx_data, error_flag;
uint32_t temp[4];
//CRC Calculation
uint32_t CRCValue = 0;
uint32_t ExpectedCRCValue = 0;
uint32_t Data[BUFFER_SIZE]= {0x00000000, 0x00000011, 0x000000AA, 0x000000CC, 0x0AEC5781};
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_SPI1_Init(void);
static void MX_RTC_Init(void);
static void MX_ADC_Init(void);
static void MX_I2C1_Init(void);
static void MX_TIM3_Init(void);
static void MX_TIM5_Init(void);
static void MX_TIM9_Init(void);
static void MX_USART1_UART_Init(void);
static void MX_TIM2_Init(void);
static void MX_CRC_Init(void);
int main(void)
{
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* Configure the system clock */
SystemClock_Config();
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_DMA_Init();
MX_USB_DEVICE_Init();
MX_FATFS_Init();
MX_SPI1_Init();
MX_RTC_Init();
MX_ADC_Init();
MX_I2C1_Init();
MX_TIM3_Init();
MX_TIM5_Init();
MX_TIM9_Init();
MX_USART1_UART_Init();
MX_TIM2_Init();
MX_CRC_Init();
HAL_UART_Receive_IT(&huart1, &rx_data, sizeof(rx_data));
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
if (rx_flag==1){
Data[0] =rx_buffer[0]<<24|rx_buffer[1]<<16|rx_buffer[2]<<8|rx_buffer[3];
Data[1] =rx_buffer[4]<<24|rx_buffer[5]<<16|rx_buffer[6]<<8|rx_buffer[7];
Data[2] =rx_buffer[8]<<24|rx_buffer[9]<<16|rx_buffer[10]<<8|rx_buffer[11];
Data[3] =rx_buffer[12]<<24|rx_buffer[13]<<16|rx_buffer[14]<<8|rx_buffer[15];
Data[4] =rx_buffer[16]<<24|rx_buffer[17]<<16|rx_buffer[18]<<8|rx_buffer[19];
ExpectedCRCValue = Data[4]; // 0x0AEC5781, which is fed from PC's serial terminal!
temp[0] = Data[0];
temp[1] = Data[1];
temp[2] = Data[2];
temp[3] = Data[3];
CRCValue = HAL_CRC_Accumulate(&hcrc, (uint32_t *)&temp, sizeof(temp));
if(CRCValue != ExpectedCRCValue)
{
//Error_Handler();
error_flag=1;
}
}
HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_5);
HAL_Delay(500); //250 ms delay
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
}
void SystemClock_Config(void)
{
// removed for easy readability of main task
}
static void MX_CRC_Init(void)
{
// removed for easy readability of main task
}
static void MX_USART1_UART_Init(void)
{
// removed for easy readability of main task
}
static void MX_DMA_Init(void)
{
// removed for easy readability of main task
}
static void MX_GPIO_Init(void)
{
// removed for easy readability of main task
}
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
if (huart->Instance==USART1)
{
//if the data is not being received, clear the buffer
if(rx_index ==0)
{
for (int i=0; i<20; i++)
{
rx_buffer[i]=0;
}
}
//if the character received is other than 'enter' ASCII13, save the data in buffer
if(rx_data!=13)
{
rx_buffer[rx_index++]=rx_data;
}
else
{
rx_index=0;
rx_flag=1; // turn the rx_flag 'ON'
HAL_UART_Transmit_IT(&huart1, rx_buffer, sizeof(rx_buffer)); // transmit the data via UART
}
HAL_UART_Receive_IT(&huart1, &rx_data, 1); // restart the interrupt reception mode & receive only 1 char at a time!
}
}
/*
Alternative while loop: (where the crc calculation is stable but wrong)
Moreover, I tried using flow control flag (i.e. rx_flag=0), but still no sucess, the CRC calculation result is wrong, probably the temp[4] variable was not filled or floating/instable!
*/
while (1)
{
if (rx_flag==1){
Data[0] =rx_buffer[0]<<24|rx_buffer[1]<<16|rx_buffer[2]<<8|rx_buffer[3];
Data[1] =rx_buffer[4]<<24|rx_buffer[5]<<16|rx_buffer[6]<<8|rx_buffer[7];
Data[2] =rx_buffer[8]<<24|rx_buffer[9]<<16|rx_buffer[10]<<8|rx_buffer[11];
Data[3] =rx_buffer[12]<<24|rx_buffer[13]<<16|rx_buffer[14]<<8|rx_buffer[15];
Data[4] =rx_buffer[16]<<24|rx_buffer[17]<<16|rx_buffer[18]<<8|rx_buffer[19];
temp[0] = Data[0];
temp[1] = Data[1];
temp[2] = Data[2];
temp[3] = Data[3];
ExpectedCRCValue = Data[4]; // 0x0AEC5781
HAL_Delay(500);
CRCValue = HAL_CRC_Accumulate(&hcrc, (uint32_t *)&temp, sizeof(temp));
if(CRCValue != ExpectedCRCValue)
{
error_flag=1;
}
rx_flag=0; // set the rx_flag as false
}
HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_5);
HAL_Delay(500); //250 ms delay
}Output:
The uint32_t CRCValue changes every cycle, although the same rx_data is sent or Data[0-3] and temp[0-3] are same!
What is wrong here? Please help!
Regards,
Thangaraj
I fixed the mistake in the code and now it works perfect!
/* USER CODE BEGIN PV */
uint8_t aintialText[] = "\r\nUSART Example\r\n";
uint8_t rx_buffer[RX_BUFFER_SIZE], rx_flag, rx_index, rx_data, error_flag, data_fill;
//CRC Calculation
uint32_t CRCValue = 0;
uint32_t ExpectedCRCValue = 0;
uint32_t temp[4] = {0x00000000, 0x00000011, 0x000000AA, 0x000000CC};
uint32_t Data[BUFFER_SIZE] = {0x00000000, 0x00000011, 0x000000AA, 0x000000CC, 0x0AEC5781};
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_DMA_Init();
MX_USB_DEVICE_Init();
MX_FATFS_Init();
MX_SPI1_Init();
MX_RTC_Init();
MX_ADC_Init();
MX_I2C1_Init();
MX_TIM3_Init();
MX_TIM5_Init();
MX_TIM9_Init();
MX_USART1_UART_Init();
MX_TIM2_Init();
MX_CRC_Init();
/* USER CODE BEGIN 2 */
/* Initiate Continuous reception */
HAL_UART_Receive_IT(&huart1, &rx_data, sizeof(rx_data));
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
if (rx_flag==1){
Data[0] =rx_buffer[0]<<24|rx_buffer[1]<<16|rx_buffer[2]<<8|rx_buffer[3];
Data[1] =rx_buffer[4]<<24|rx_buffer[5]<<16|rx_buffer[6]<<8|rx_buffer[7];
Data[2] =rx_buffer[8]<<24|rx_buffer[9]<<16|rx_buffer[10]<<8|rx_buffer[11];
Data[3] =rx_buffer[12]<<24|rx_buffer[13]<<16|rx_buffer[14]<<8|rx_buffer[15];
Data[4] =rx_buffer[16]<<24|rx_buffer[17]<<16|rx_buffer[18]<<8|rx_buffer[19];
temp[0] = Data[0];
temp[1] = Data[1];
temp[2] = Data[2];
temp[3] = Data[3];
ExpectedCRCValue = Data[4]; // 0x0AEC5781
HAL_Delay(500);
CRCValue = HAL_CRC_Calculate(&hcrc, (uint32_t *)&temp, 4U);
if(CRCValue != ExpectedCRCValue)
{
error_flag=1;
}
rx_flag=0; // set the rx_flag as false
}
HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_5);
HAL_Delay(500); //250 ms delay
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
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;
if (HAL_CRC_Init(&hcrc) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN CRC_Init 2 */
/* USER CODE END CRC_Init 2 */
}
.
.
.
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
if (huart->Instance==USART1)
{
//if the data is not being received, clear the buffer
if(rx_index ==0)
{
for (int i=0; i<20; i++)
{
rx_buffer[i]=0;
}
}
//if the character received is other than 'enter' ASCII13, save the data in buffer
if(rx_data!=13)
{
rx_buffer[rx_index++]=rx_data;
}
else
{
rx_index=0;
rx_flag=1; // turn the rx_flag 'ON'
HAL_UART_Transmit_IT(&huart1, rx_buffer, sizeof(rx_buffer)); // transmit the data via UART
}
HAL_UART_Receive_IT(&huart1, &rx_data, 1); // restart the interrupt reception mode & receive only 1 char at a time!
}
}The mistake was:
CRCValue = HAL_CRC_Accumulate(&hcrc, (uint32_t *)&temp, sizeof(temp));This was the reason, the calculated CRC value was incorrect before!
Now, I modified as:
CRCValue = HAL_CRC_Calculate(&hcrc, (uint32_t *)&temp, sizeof(&temp));Now, I got the expected CRC value (see the screenshot)!
Please help if anybody has any suggestion!
Thank you!
Regards,
Thangaraj
