各位CRC都是怎么用的？

/*---------------------------------------------------------------------------------------------------------*/

/*  MAIN function                                                                                          */

/*---------------------------------------------------------------------------------------------------------*/

int main(void)

{

    const uint16_t u16CRCSrcPattern[] = {0x3231, 0x3433, 0x3635, 0x3837};

    uint32_t i, u32TargetChecksum = 0xA12B, u32CalChecksum = 0;



    /* Init System, peripheral clock and multi-function I/O */

    SYS_Init();



    /* Init UART0 for printf */

    UART0_Init();



    printf("\n\nCPU [url=home.php?mod=space&uid=72445]@[/url] %d Hz\n", SystemCoreClock);

    printf("+---------------------------------------------+\n");

    printf("|    CRC-CCITT Polynomial Mode Sample Code    |\n");

    printf("+---------------------------------------------+\n\n");



    printf("# Calculate [0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38] CRC-CCITT checksum value.\n");

    printf("    - Seed value is 0xFFFF             \n");

    printf("    - CPU write data length is 16-bit \n");

    printf("    - Checksum complement disable    \n");

    printf("    - Checksum reverse disable       \n");

    printf("    - Write data complement disable  \n");

    printf("    - Write data reverse disable     \n");

    printf("    - Checksum should be 0x%X        \n\n", u32TargetChecksum);



    /* Configure CRC controller for CRC-CCITT CPU mode */

    CRC_Open(CRC_CCITT, 0, 0xFFFF, CRC_CPU_WDATA_16);



    /* Start to execute CRC-CCITT operation */

    for(i = 0; i < sizeof(u16CRCSrcPattern) / sizeof(u16CRCSrcPattern[0]); i++)

    {

        CRC_WRITE_DATA((u16CRCSrcPattern[i]));

    }



    /* Get CRC-CCITT checksum value */

    u32CalChecksum = CRC_GetChecksum();

    printf("CRC checksum is 0x%X ... %s.\n", u32CalChecksum, (u32CalChecksum == u32TargetChecksum) ? "PASS" : "FAIL");



    /* Disable CRC function */

    CLK_DisableModuleClock(CRC_MODULE);



    while(1);

}