NXP Semiconductors MPC5644A, Reference Manual, Page: 1242 / 1735

Cyclic Redundancy Checker (CRC) Unit
MPC5644A Microcontroller Reference Manual, Rev. 6
1242 Freescale Semiconductor
29.4.1 CRC Configuration Register (CRC_CFG)
Offset: PM 0x0000
PM 0x0010
PM 0x0020
Access: User read/write
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
R 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
W
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
R 0 0 0 0 0 0 0 0 0 0 0 0 0
PO
L
Y
G
SW
AP
INV
W
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0/1
1
1
Reset value is 1 for Context 2 and 0 for Context 1 and Context 3.
0 0
Figure 29-2. CRC Configuration Register (CRC_CFG)
Table 29-2. CRC_CFG field descriptions
Field Description
0–28 Reserved
29
POLYG
POLYG: Polynomial selection
0: CRC-CCITT polynomial.
1: CRC-32 polynomial.
This bit can be read and written by software.
This bit can be written only during the configuration phase.
30
SWAP
SWAP: SWAP selection
0: No swap selection applied on the CRC_OUTP content
1: Swap selection (MSB

LSB, LSB

MSB) applied on the CRC_OUTP content. In case of
CRC-CCITT polynomial the swap operation is applied on the 16 LSB bits.
This bit can be read and written by software.
This bit can be written only during the configuration phase.
31
INV
INV: INV selection
0: No inversion selection applied on the CRC_OUTP content
1: Inversion selection (bit x bit) applied on the CRC_OUTP content. In case of CRC-CCITT polynomial the
inversion operation is applied on the 16 LSB bits.
This bit can be read and written by software.
This bit can be written only during the configuration phase.