Delta Electronics AC Motor Drive VFD-G User Manual page 131

Chapter 4 Parameters|
The following is an example of CRC generation using C language. The function takes two
arguments:
Unsigned char* data
Unsigned char length
The function returns the CRC values as a type of unsigned integer.
unsigned int crc_chk(unsigned char* data, unsigned char length){
int j;
unsigned int reg_crc=0xFFFF;
while(length--){
reg_crc ^= *data++;
for(j=0;j<8;j++){
if(reg_crc & 0x01){ /* LSB(b0)=1 */
}else{
}
}
}
return reg_crc;
}
4-80
Command message:
Data starting address
a pointer to the message buffer
the quantity of bytes in the message buffer
reg_crc=(reg_crc>>1) ^ 0xA001;
reg_crc=reg_crc >>1;
ADR
CMD
Number of data
(word)
CRC CHK Low
CRC CHK High
01H
03H
02H
02H
00H
02H
6FH
F7H
Revision July 2008, EG03, SW V1.06