HarwareCRCExample

1. Basic example of CRC calculation using append

       #include "HardwareCRC.h"
       
       uint8_t testArray[] = {1,2,3,4,5};
    
      //This method have to be called in main function in main.c file.
      void app(void){
      
       crc.begin(); //Enable unit
       crc.reset(0x00); //Reset calculation and set init value to 0
       crc.setPolynomial8(CRC8_POLY); //Set default CRC-8 polynomial (X^8 + X^5 + X^4 + 1)
       // or use crc.setPolynomial8(CRC_X5 | CRC_X4 | CRC_X0); //(X^8 + X^5 + X^4 + 1)
       crc.setInputReverse(false); //Disable input reflection
       crc.setOutputReverse(false); //Disable output reflection
      
       //Bytes can be appended by one
       for(int i = 0; i < 4; i++){
           crc.append(testArray[i]);
       }
       uint32_t CRC_result = crc.append(testArray[4], 0xFF); //Append last byte and set finalXOR to 0xFF
      
       //Or whole array can be appended at once:
       /*
       uint32_t CRC_result = crc.append(testArray, 5, 0xFF);
           */
      
       //Infinite loop
       while(1){
           // Nothing here.
       }
      }
   * 

2. Basic example of CRC calculation using compute

    #include "HardwareCRC.h"
    
    uint8_t testArray[] = {1,2,3,4,5};
    
   //This method have to be called in main function in main.c file.
   void app(void){
    
    crc.begin(); //Enable unit
    //crc.reset(0x00); - don't need to be called when using compute
    crc.setPolynomial8(CRC8_POLY); //Set default CRC-8 polynomial (X^8 + X^5 + X^4 + 1)
    // or use crc.setPolynomial8(CRC_X5 | CRC_X4 | CRC_X0); //(X^8 + X^5 + X^4 + 1)
    crc.setInputReverse(false); //Disable input reflection
    crc.setOutputReverse(false); //Disable output reflection
    
    uint32_t CRC_result = crc.compute(testArray, 5, 0x00, 0xFF); //Compute CRC, set init value to 0x00 and finalXOR to 0xFF
    
    //Infinite loop
    while(1){
        // Nothing here.
    }
   }

3. Basic example of CRC calculation using computeAndWriteToEnd

    #include "HardwareCRC.h"
    
    uint8_t testArray[6] = {1,2,3,4,5}; //We need to reserve last byte for CRC.
    //NOTE: When CRC-16 is used, 2 bytes has to be reserved and when CRC-32 is used, 4 bytes has to be reserved
    
   //This method have to be called in main function in main.c file.
   void app(void){
    
    crc.begin(); //Enable unit
    //crc.reset(0x00); - don't need to be called when using compute
    crc.setPolynomial8(CRC8_POLY); //Set default CRC-8 polynomial (X^8 + X^5 + X^4 + 1)
    // or use crc.setPolynomial8(CRC_X5 | CRC_X4 | CRC_X0); //(X^8 + X^5 + X^4 + 1)
    crc.setInputReverse(false); //Disable input reflection
    crc.setOutputReverse(false); //Disable output reflection
    
    uint32_t CRC_result = crc.computeAndWriteToEnd(testArray, 5, 0x00, 0xFF); //Compute CRC, set init value to 0x00 and finalXOR to 0xFF
    
    //CRC result is now attached at the end of the array
    uint32_t CRC_result2 = testArray[5];
    
    //CRC_result == CRC_result2
    
    //Infinite loop
    while(1){
        // Nothing here.
    }
   }

4. Basic example of CRC check

    #include "HardwareCRC.h"
    
    uint8_t testArray[6] = {1,2,3,4,5}; //We need to reserve last byte for CRC.
    //NOTE: When CRC-16 is used, 2 bytes has to be reserved and when CRC-32 is used, 4 bytes has to be reserved
    
   //This method have to be called in main function in main.c file.
   void app(void){
    
    crc.begin(); //Enable unit
    //crc.reset(0x00); - don't need to be called when using compute
    crc.setPolynomial8(CRC8_POLY); //Set default CRC-8 polynomial (X^8 + X^5 + X^4 + 1)
    // or use crc.setPolynomial8(CRC_X5 | CRC_X4 | CRC_X0); //(X^8 + X^5 + X^4 + 1)
    crc.setInputReverse(false); //Disable input reflection
    crc.setOutputReverse(false); //Disable output reflection
    
    crc.computeAndWriteToEnd(testArray, 5, 0x00, 0xFF); //Compute CRC and append it at the end, set init value to 0x00 and finalXOR to 0xFF
    
    //Now we will check, if testArray is valid
    bool valid = crc.check(testArray, 5, 0x00, 0xFF);
    
    //Now we will check, if testArray is valid also after small change
    testArray[2] = 12;
    bool stillValid = crc.check(testArray, 5, 0x00, 0xFF);
    
    //Infinite loop
    while(1){
        // Nothing here.
    }
   }

5. Example of CRC-32 calculation

    #include "HardwareCRC.h"
    
    uint8_t testArray[9] = {1,2,3,4,5}; //We need to reserve last 4 bytes for CRC.
    
   //This method have to be called in main function in main.c file.
   void app(void){
    
    crc.begin(); //Enable unit
    //crc.reset(0x00); - don't need to be called when using compute
    crc.setPolynomial32(); //Set default CRC-32 polynomial
    crc.setInputReverse(true); //Enable input reflection
    crc.setOutputReverse(true); //Enable output reflection
    
    crc.computeAndWriteToEnd(testArray, 5, 0xFFFFFFFFUL, 0xFFFFFFFFUL); //Compute CRC and append it at the end, set init value to 0xFFFFFFFFUL and finalXOR to 0xFFFFFFFFUL
    
    //Now we will check, if testArray is valid
    bool valid = crc.check(testArray, 5, 0xFFFFFFFFUL, 0xFFFFFFFFUL);
    
    //Now we will check, if testArray is valid also after small change
    testArray[2] = 12;
    bool stillValid = crc.check(testArray, 5, 0xFFFFFFFFUL, 0xFFFFFFFFUL);
    
    //Infinite loop
    while(1){
        // Nothing here.
    }
   }

Note

Those examples works only with c++, but STM32CubeIDE does not allow you to change main.c to main.cpp, so you have to create own c++ file, and include it in main.h. In your cpp file create function, that will be called in main() function. In this case, function name is app() and is called in main() function between tags USER CODE BEGIN 2 and USER CODE END 2.

See also

Hardware CRC documentation

HardwareCRC