如何设置STM32生成标准CRC32

问题描述

我正在尝试使用STM32L4硬件模块生成CRC.我想验证fatfs文件，因此基本上我有字节数组.我正在使用此CRC 生成器.

I am trying to generate CRC with STM32L4 hardware modul. I would like to validate fatfs files so basically I have byte arrays. I am using this CRC generator.

不幸的是，我无法弄清楚如何设置STM32L4来生成相同的结果.我需要CRC32，我有

Unfortunately I cannot figure out how to set STM32L4 to generate the same result. I need CRC32 and I have

配置:

hcrc.Instance = CRC;

/* The default polynomial is not used. It is required to defined it in CrcHandle.Init.GeneratingPolynomial*/
hcrc.Init.DefaultPolynomialUse    = DEFAULT_POLYNOMIAL_DISABLE;
/* Set the value of the polynomial */
hcrc.Init.GeneratingPolynomial    = 0x4C11DB7;
//hcrc.Init.GeneratingPolynomial    = 0xFB3EE248;
hcrc.Init.CRCLength= CRC_POLYLENGTH_32B;
/* The default init value is used */
/* The default init value is not used */
hcrc.Init.DefaultInitValueUse     = DEFAULT_INIT_VALUE_ENABLE;

/* User init value is used instead */
//hcrc.Init.InitValue               = 0;
hcrc.Init.InputDataInversionMode = CRC_INPUTDATA_INVERSION_NONE;
//hcrc.Init.InputDataInversionMode = CRC_INPUTDATA_INVERSION_BYTE;
/* The input data are inverted by word */
//hcrc.Init.InputDataInversionMode  = CRC_INPUTDATA_INVERSION_WORD;

//hcrc.Init.OutputDataInversionMode = CRC_OUTPUTDATA_INVERSION_ENABLE;
hcrc.Init.OutputDataInversionMode = CRC_OUTPUTDATA_INVERSION_DISABLE;
hcrc.InputDataFormat = CRC_INPUTDATA_FORMAT_BYTES;
HAL_CRC_Init(&hcrc);

测试:

uint8_t test[] = {49,50,51,52};
uint32_t uwCRCValue = HAL_CRC_Calculate(&hcrc,(uint32_t *) test, 4);

结果:A695C4AA

我没主意了.我成功使用uint32_t test[]并将输入设置为hcrc.InputDataFormat = CRC_INPUTDATA_FORMAT_BYTES;的一种方法不幸的是我有uint8_t ...

I am out of ideas. There is one way that I am succeeded with it to have uint32_t test[] and input is set to hcrc.InputDataFormat = CRC_INPUTDATA_FORMAT_BYTES;Unfortunately I have uint8_t...

推荐答案

使用以下代码计算cc32. STM32 CRC单元的CRC32 calc与我们的标准CRC32不同，它使用大字节序，并且不会与0xFFFFFFFF进行XOR.

Use the following code to calc cc32. CRC32 calc by STM32 CRC unit is not the same as our standard CRC32, it did use big endian, and it will not XOR with 0xFFFFFFFF.

u32 CRC32_ForBytes(u8 *pData, u32 uLen);

#define UNUSED(x) ((void)(x))

/**
 * @brief  CRC functions
 */
#define __HAL_RCC_CRC_CLK_ENABLE()   do { \
                                        __IO uint32_t tmpreg; \
                                        SET_BIT(RCC->AHBENR, RCC_AHBENR_CRCEN);\
                                        /* Delay after an RCC peripheral clock enabling */\
                                        tmpreg = READ_BIT(RCC->AHBENR, RCC_AHBENR_CRCEN);\
                                        UNUSED(tmpreg); \
                                      } while(0)

#define __HAL_RCC_CRC_CLK_DISABLE()       (RCC->AHBENR &= ~(RCC_AHBENR_CRCEN))

#define CRC32_POLYNOMIAL                        ((u32)0xEDB88320)
#define RCC_CRC_BIT                             ((u32)0x00001000)


/**
 * @brief  Calc CRC32 for data in bytes
 * @param  pData Buffer pointer
 * @param  uLen  Buffer Length
 * @retval CRC32 Checksum
 */
u32 CRC32_ForBytes(u8 *pData,u32 uLen)
{
    u32 uIndex= 0,uData = 0,i;
    uIndex = uLen >> 2;

    __HAL_RCC_CRC_CLK_ENABLE();

    /* Reset CRC generator */
    CRC_ResetDR();

    while(uIndex--)
    {
#ifdef USED_BIG_ENDIAN
        uData = __REV((u32*)pData);
#else
        ((u8 *)&uData)[0] = pData[0];
        ((u8 *)&uData)[1] = pData[1];
        ((u8 *)&uData)[2] = pData[2];
        ((u8 *)&uData)[3] = pData[3];
#endif
        pData += 4;
        uData = revbit(uData);
        CRC->DR = uData;
    }
    uData = revbit(CRC->DR);
    uIndex = uLen & 0x03;
    while(uIndex--)
    {
        uData ^= (u32)*pData++;
        for(i = 0;i < 8;i++)
          if (uData & 0x1)
            uData = (uData >> 1) ^ CRC32_POLYNOMIAL;
          else
            uData >>= 1;
    }

    __HAL_RCC_CRC_CLK_DISABLE();

    return uData^0xFFFFFFFF;
}

static u32 revbit(u32 uData)
{
    u32 uRevData = 0,uIndex = 0;
    uRevData |= ((uData >> uIndex) & 0x01);
    for(uIndex = 1;uIndex < 32;uIndex++)
    {
        uRevData <<= 1;
        uRevData |= ((uData >> uIndex) & 0x01);
    }
    return uRevData;
}

像这样计算您的CRC32:

Calc your CRC32 like this:

u32 uwCRCValue = CRC32_ForBytes(&test, 4);

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