Delta Electronics DVP10MC11T [295/375] Appendix a

Appendix A

DVP-MC operating manual A-11

Step 6: Repeat the action of step 2 and step 5 for the next byte in the command message till all bytes are

finished processing. The last content in CRC register is CRC check value. When CRC check value

in command message is transmitted, the high and low byte in calculated CRC check value must

exchange with each other, i.e. the low byte is transmitted first.

Example on calculation of CRC check value with C language

Unsigned char* data  // Pointer of command message content

Unsigned char length  // Length of command message content

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） reg_crc=（reg_crc>>1） ^ 0Xa001; /* LSB（b0）=1 */

else reg_crc=reg_crc >>1;

}

return reg_crc; // the value that sent back to the CRC register finally

}