TMS320F28377D: Fletcher Checksum with UID

Hi,

My customer did the  Fletcher Checksum with UID,

But the results told us that some chips using big endian mode , and others using little endian mode.

Could TI explain which mode using in F28377D?

Or any wrong code with below calculate algorithm program?

device 1 UID:

uint16_t UID_Data1[]={0x2c6d ,0x81b9 ,0x1656 ,0x472e ,0x4899 ,0xfa9a ,0x4e7f ,0x9e3b ,0x51a8 ,0xda30 ,0x2ca5 ,0xcb9e ,0x0008 ,0x64e5 ,0x33c2 ,0xc4a4};

uint16_t UID_Data2[]={0x81b9 ,0x2c6d ,0x472e ,0x1656 ,0xfa9a ,0x4899 ,0x9e3b ,0x4e7f ,0xda30 ,0x51a8 ,0xcb9e ,0x2ca5 ,0x64e5 ,0x0008 ,0xc4a4 ,0x33c2};

calculate result:

UID_CRC1       unsigned long  0x4804C4A4 (Hex)         

UID_CRC2       unsigned long  0x33C2C4A4 (Hex)        

device 2 UID:

uint16_t UID_Data3[]={0x9dc8 ,0x289b ,0x3e8e ,0xc11b ,0x3e8c ,0xbff4 ,0xe00e ,0xea60 ,0xbbb3 ,0xc382 ,0x930c ,0x1b7d ,0x0077 ,0xd980 ,0x3929 ,0x96b6};

uint16_t UID_Data4[]={0x289b ,0x9dc8 ,0xc11b ,0x3e8e ,0xbff4 ,0x3e8c ,0xea60 ,0xe00e ,0xc382 ,0xbbb3 ,0x1b7d ,0x930c ,0xd980 ,0x0077 ,0x96b6 ,0x3929};

 calculate result:

UID_CRC3       unsigned long  0x392996B6 (Hex)         

UID_CRC4       unsigned long  0x36C596B6 (Hex)         

calculate algorithm program as below:

--------<declare>--------------------------------------

uint32_t fletch32(uint16_t const * pu16Data, uint32_t length, uint32_t seed);

// UID 0x000703C0  ==>93EEBC4E   5C64CAE9    7597B4B0    4DF20580    0B333C18    650D013C    000D1F39    62E7C220

uint16_t UID_Data2[]={0xBC4E ,0x93EE ,0xCAE9 ,0x5C64 ,0xB4B0 ,0x7597 ,0x0580 ,0x4DF2 ,0x3C18 ,0x0B33 ,0x013C ,0x650D ,0x1F39 ,0x000D ,0xC220 ,0x62E7};

uint32_t UID_CRC=0,seed = 0xFFFFFFFF;

-----<main()>-----------------------------

    UID_CRC=fletch32(UID_Data2,14,seed);

------<function>---------------------------------------------

//seed = 0xFFFFFFFF;

uint32_t fletch32(uint16_t const * pu16Data, uint32_t length, uint32_t seed)

{

uint32_t u32Sum1 = 0xFFFFU & seed, u32Sum2 = 0xFFFFU & (seed >> 16U);

uint16_t u32Index, idx;

uint16_t data;

for(u32Index=0U;u32Index < length; u32Index++)

{

idx = u32Index^1; // little endian mode otherwise use u32Index only

data = pu16Data[idx];

u32Sum1 += data;

u32Sum1 = (u32Sum1 >> 16U) + (u32Sum1 & 0xFFFFU);

u32Sum2 += u32Sum1;

u32Sum2 = (u32Sum2 >> 16U) + (u32Sum2 & 0xFFFFU);

}

return ( (u32Sum2 << 16U) | u32Sum1);

}

best regards,

Simen