Freescale Semiconductor MK22FN256VDC12, Reference Manual

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CRC_CTRL field descriptions
Field Description
31–30
TOT
Type Of Transpose For Writes
Defines the transpose configuration of the data written to the CRC data register. See the description of the
transpose feature for the available transpose options.
00 No transposition.
01 Bits in bytes are transposed; bytes are not transposed.
10 Both bits in bytes and bytes are transposed.
11 Only bytes are transposed; no bits in a byte are transposed.
29–28
TOTR Type Of Transpose For Read
Identifies the transpose configuration of the value read from the CRC Data register. See the description of
the transpose feature for the available transpose options.
00 No transposition.
01 Bits in bytes are transposed; bytes are not transposed.
10 Both bits in bytes and bytes are transposed.
11 Only bytes are transposed; no bits in a byte are transposed.
27
Reserved
This field is reserved.
This read-only field is reserved and always has the value 0.
26
FXOR
Complement Read Of CRC Data Register
Some CRC protocols require the final checksum to be XORed with 0xFFFFFFFF or 0xFFFF. Asserting
this bit enables on the fly complementing of read data.
0 No XOR on reading.
1 Invert or complement the read value of the CRC Data register.
25
WAS
Write CRC Data Register As Seed
When asserted, a value written to the CRC data register is considered a seed value. When deasserted, a
value written to the CRC data register is taken as data for CRC computation.
0 Writes to the CRC data register are data values.
1 Writes to the CRC data register are seed values.
24
TCRC
Width of CRC protocol.
0 16-bit CRC protocol.
1 32-bit CRC protocol.
23–0
Reserved
This field is reserved.
This read-only field is reserved and always has the value 0.
31.3 Functional description
Chapter 31 Cyclic Redundancy Check (CRC)
K22F Sub-Family Reference Manual , Rev. 3, 7/2014
Freescale Semiconductor, Inc. 675