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User Manual of A90 Series Inverter

289

while(Length--)

{

crc_value ^= *Data++;

for(i=0;i<8;i++)

{

if(crc_value & 0x0001)

{

crc_value = (crc_value>>1)^ 0xa001;

}

else

{

crc_value = crc_value>>1;

}

return(crc_value);

}

This only describes the theory of CRC check and requires a long execution time.

Especially when the check data is long, the calculation time will be too long. Thus, the

following two table lookup methods are applied for 16-bit and 8-bit controllers,

respectively.



CRC16 lookup table for the 8-bit processor: (The high byte in the final result of this

program is in front. Please reverse it during sending.)

const Uint8 crc_l_tab[256] = {

0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,

0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,

0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,

0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,

0x00,0xC1,0x81,0x40,0x01,0xC0,0x80,0x41,0x01,0xC0,0x80,0x41,0x00,0xC1,0x81,0x40,

Sinee A90-4T5R6B User Manual

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