
UM10800
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© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
361 of 487
NXP Semiconductors
UM10800
Chapter 23: LPC82x CRC engine
23.6 Register description
23.6.1 CRC mode register
23.6.2 CRC seed register
23.6.3 CRC checksum register
This register is a Read-only register containing the most recent checksum. The read
request to this register is automatically delayed by a finite number of wait states until the
results are valid and the checksum computation is complete.
Table 298. Register overview: CRC engine (base address 0x5000 0000)
Name
Access
Address
offset
Description
Reset value
Reference
MODE
R/W
0x000
CRC mode register
0x0000 0000
SEED
R/W
0x004
CRC seed register
0x0000 FFFF
SUM
RO
0x008
CRC checksum register
0x0000 FFFF
WR_DATA
WO
0x008
CRC data register
-
Table 299. CRC mode register (MODE, address 0x5000 0000) bit description
Bit
Symbol
Description
Reset value
1:0
CRC_POLY
CRC polynom:
1X= CRC-32 polynomial
01= CRC-16 polynomial
00= CRC-CCITT polynomial
00
2
BIT_RVS_WR
Data bit order:
1= Bit order reverse for CRC_WR_DATA (per byte)
0= No bit order reverse for CRC_WR_DATA (per byte)
0
3
CMPL_WR
Data complement:
1= 1’s complement for CRC_WR_DATA
0= No 1’s complement for CRC_WR_DATA
0
4
BIT_RVS_SUM
CRC sum bit order:
1= Bit order reverse for CRC_SUM
0= No bit order reverse for CRC_SUM
0
5
CMPL_SUM
CRC sum complement:
1= 1’s complement for CRC_SUM
0=No 1’s complement for CRC_SUM
0
31:6 Reserved
Always 0 when read
0x0000000
Table 300. CRC seed register (SEED, address 0x5000 0004) bit description
Bit
Symbol
Description
Reset value
31:0
CRC_SEED
A write access to this register will load CRC seed value to
CRC_SUM register with selected bit order and 1’s
complement pre-processes.
Remark:
A write access to this register will overrule the
CRC calculation in progresses.
0x0000 FFFF