Cypress FM4 Series - CRC Computing Generator Polynomial Register

CHAPTER 19: Programmable CRC
FM4 Peripheral Manual, Doc. No. 002-04856 Rev. *E 941
4.2 CRC Computing Generator Polynomial Register
CRC computing generator polynomial register (PRGCRC_POLY) specifies the generator polynomial for
CRC computing.
Register configuration
Address: +0x00
bit 31 0
Field
PRGCRC_POLY[31:0]
Attribute
R/W
Initial value
0x 04C1 1DB7
Register functions
[bit31:0] PRGCRC_POLY (Generator Polynomial)
Access
Application
Write
Sets generator polynomial for CRC computing.
Read
Reads the register setting value.
The PRGCRC_POLY register specifies the generator polynomial of CRC computing before CRC
computing starts. The following section explains how to calculate the value which is specified for the
PRGCRC_POLY register from generator polynomial.
 Specify "1" when a term exists for generator polynomial, or specify "0" when a term does not exist.
 You do not need to specify the term of the largest degree for generator polynomial. Remove the value.
 Specify the values from the term of largest degree -1 by left justified. If the CRC length is less than 32,
padding with "0" for the right side unused section.
Table 4-2 shows an example setting of generator polynomial and the PRGCRC_POLY register.
Table 4-2 Example setting of PRGCRC_POLY
CRC
length
Generator polynomial
PRGCRC_POLY
Setting value
32
x
32
+x
26
+x
23
+x
22
+x
16
+x
12
+x
11
+x
10
+x
8
+x
7
+x
5
+x
4
+x
2
+x+1
0x 04C1 1DB7
24
x
24
+ x
23
+ x
18
+ x
17
+ x
14
+ x
11
+ x
10
+ x
7
+ x
6
+ x
5
+ x
4
+x
3
+x+1
0x 864C FB00
16
x
16
+x
12
+x
5
+1
0x 1021 0000
11
x
11
+x
9
+x
7
+x
6
+x
5
+x+1
0x 5C60 0000
8
x
8
+x
2
+x+1
0x 0700 0000
5
x
5
+x
4
+x
2
+1
0x A800 0000
1
x+1
0x 8000 0000
The following explains an example of setting value calculation when generator polynomial is
x
11
+ x
9
+ x
7
+ x
6
+ x
5
+ x+1.
 Specify "1" when a term exists, or specify "0" when a term does not exist.
1010 1110 0011 (binary)
 Remove the term of the largest degree.
010 1110 0011 (binary)