CRC的Seed是什么啊？

/**************************************************************************//**

 * [url=home.php?mod=space&uid=288409]@file[/url]     main.c

 * [url=home.php?mod=space&uid=895143]@version[/url]  V3.00

 * $Revision: 2 $

 * $Date: 16/10/25 4:28p $

 * [url=home.php?mod=space&uid=247401]@brief[/url]    Implement CRC in CRC-8 mode and get the CRC checksum result.

 * @note

 * Copyright (C) 2016 Nuvoton Technology Corp. All rights reserved.

 ******************************************************************************/

#include <stdio.h>

#include "NUC029xGE.h"





#define PLL_CLOCK       72000000





void SYS_Init(void)

{

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

    /* Init System Clock                                                                                       */

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

    /* Enable HIRC clock */

    CLK_EnableXtalRC(CLK_PWRCTL_HIRCEN_Msk);



    /* Waiting for HIRC clock ready */

    CLK_WaitClockReady(CLK_STATUS_HIRCSTB_Msk);



    /* Switch HCLK clock source to HIRC */

    CLK_SetHCLK(CLK_CLKSEL0_HCLKSEL_HIRC, CLK_CLKDIV0_HCLK(1));



    /* Enable HXT */

    CLK_EnableXtalRC(CLK_PWRCTL_HXTEN_Msk);



    /* Waiting for clock ready */

    CLK_WaitClockReady(CLK_STATUS_HXTSTB_Msk);



    /* Set core clock as PLL_CLOCK from PLL and SysTick source to HCLK/2*/

    CLK_SetCoreClock(PLL_CLOCK);

    CLK_SetSysTickClockSrc(CLK_CLKSEL0_STCLKSEL_HCLK_DIV2);



    /* Enable peripheral clock */

    CLK_EnableModuleClock(UART0_MODULE);

    CLK_EnableModuleClock(CRC_MODULE);



    /* Peripheral clock source */

    CLK_SetModuleClock(UART0_MODULE, CLK_CLKSEL1_UARTSEL_PLL, CLK_CLKDIV0_UART(1));



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

    /* Init I/O Multi-function                                                                                 */

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

    /* Set multi-function pins for UART0 RXD and TXD */

    SYS->GPA_MFPL &= ~(SYS_GPA_MFPL_PA2MFP_Msk | SYS_GPA_MFPL_PA3MFP_Msk);

    SYS->GPA_MFPL |= (SYS_GPA_MFPL_PA3MFP_UART0_RXD | SYS_GPA_MFPL_PA2MFP_UART0_TXD);

}



void UART0_Init(void)

{

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

    /* Init UART                                                                                               */

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

    /* Reset UART module */

    SYS_ResetModule(UART0_RST);



    /* Configure UART0 and set UART0 Baudrate */

    UART_Open(UART0, 115200);

}



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

/*  MAIN function                                                                                          */

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

int main(void)

{

    const uint8_t acCRCSrcPattern[] = {0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39};

    uint32_t i, u32TargetChecksum = 0x58, u32CalChecksum = 0;



    /* Unlock protected registers */

    SYS_UnlockReg();



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

    SYS_Init();



    /* Lock protected registers */

    SYS_LockReg();



    /* 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-8 Polynomial Mode Sample Code    |\n");

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



    printf("# Calculate [0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39] CRC-8 checksum value.\n");

    printf("    - Seed value is 0x5A             \n");

    printf("    - CPU write data length is 8-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-8 CPU mode */

    CRC_Open(CRC_8, 0, 0x5A, CRC_CPU_WDATA_8);



    /* Start to execute CRC-8 CPU operation */

    for(i = 0; i < sizeof(acCRCSrcPattern); i++)

    {

        CRC_WRITE_DATA((acCRCSrcPattern[i] & 0xFF));

    }



    /* Get CRC-8 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);

}



/*** (C) COPYRIGHT 2016 Nuvoton Technology Corp. ***/