Renesas M16C Series User Manual page 282

M30240 Group
b15
(1) Setting 0000
16
(2) Setting 01
16
b15
The code resulting from sending 01
16 12 5
(X + X + X + 1), becomes the remainder resulting from dividing (1000 0000) X
conformity with the modulo-2 operation.
1 0001 0000 0010 0001
Thus the CRC code becomes (1001 0001 1000 1000). Since the operation is in LSB first mode, the (1001 0001 1000 1000)
corresponds to 1189
circuit built in the M16C, switch between the LSB side and the MSB side of the input-holding bits, and carry out the CRC
operation. Also switch between the MSB and LSB of the result as stored in CRC data.
(3) Setting 23
16
b15
Figure 2.109: Operation of CRC Calculation Circuit
Rev.1.00 Sep 24, 2003 Page 264 of 360
b7
1189
16
in LSB first mode is (1000 0000). Thus the CRC code in the generating polynomial,
16
LSB
with the law given below.
1000 0000 0000 0000 0000 0000
1000 1000 0001 0000 1
1000 0001 0000 1000 0
1000 1000 0001 0000 1
1001 0001 1000 1000
LSB
9 8 1
in hexadecimal notation. If the CRC operation in MSB first mode is necessary in the CRC operation
16
b7
0A41
16
b0
CRC data register CRCD
[03BD
b0
CRC input register CRCIN
[03BE
2 cycles
After CRC calculation is complete
b0
CRC data register CRCD
[03BD
Stores CRC code
16
MSB
1000 1000
MSB
1
b0
CRC input register CRCIN
[03BE
After CRC calculation is complete
b0
CRC data register CRCD
[03BD
Stores CRC code
CRC Calculation Circuit
, 03BC ]
16 16
]
16
, 03BC ]
16 16
by (1 0001 0000 0010 0001) in
Modulo-2 operation is
operation that complies
0 + 0 = 0
0 + 1 = 1
1 + 0 = 1
1 + 1 = 0
-1 = 1
]
16
, 03BC ]
16 16