Datasheet

V850ES/JG3 CHAPTER 25 CRC FUNCTION
R01UH0015EJ0300 Rev.3.00 Page 716 of 870
Sep 30, 2010
25.4 Operation
An example of the CRC operation circuit is shown below.
Figure 25-2. CRC Operation Circuit Operation Example (LSB First)
(1) Setting of CRCIN = 01H
1189H
b15 b0
b0b7
CRC code is stored
(2) CRCD register read
The code when 01H is sent LSB first is (1000 0000). Therefore, the CRC code from generation polynomial X
16
+ X
12
+
X
5
+ 1 becomes the remainder when (1000 0000) X
16
is divided by (1 0001 0000 0010 0001) using the modulo-2 operation
formula.
The modulo-2 operation is performed based on the following formula.
0 + 0 = 0
0 + 1 = 1
1 + 0 = 1
1 + 1 = 0
− 1 = 1
1 0001 0000 0010 0001 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
1000 1000
LSB
LSB
MSB
MSB
Therefore, the CRC code becomes . Since LSB first is used, this corresponds
to 1189H in hexadecimal notation.
1001
9811
0001 1000 1000