1. Addr (starting address): Store the data when calculate the CRC check code in an area starting from Dn, and this operand can only be selected from the D data register;

2. Len (data length): In bytes, one D register occupies 2 bytes, with the lower bits before the higher bits.

3. Mode (CRC Check Mode): Different types of CRC checks can be selected.

Name	Number	Polynomial	Check Code Length
CRC-16	K0	X16+X15+X2+1	2 bytes
CRC-12	K1	X12+X11+X3+X2+X+1	2 bytes
CRC-8	K2	X8+X2+X+1	1 byte
CRC-CCITT	K3	X16+X12+X5+1	2 bytes
CRC-32	K4	X32+X26+X23+X22+X16+X12+X11+X10+X8+X7+X5+X4+X2+X+1	4 bytes
CRC-32C	K5	X32+X28+X27+X26+X25+X23+X22+X20+X19+X18+X14+X13+X11+X10+X9+X8+X6+1	4 bytes

The computed checksum will follow at the end of the data.

For example, there is a data segment of 12 34 56 78 (hexadecimal) stored in registers starting with D0. So D0=0x3412, D1=0x7856, with a length of 4 bytes.

After executing CRC D0 K4 K0, the CRC checksum will be saved to D2, which is 0x107B.

Attention:

1. When the data length is odd, the checksum will immediately follow the high bit of the last register.

2. Please note that the input parameter is the byte length of the original data, and the length of the final communication data should be added with the length of the subsequent checksum.

Input/Output	Data Type	operand	Description

Instruction table:

NETWORK 000

LD M0

MOV H3412 D0

MOV H7856 D1

CRC D0 K4 K0

POP

图1 CRC