mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 197

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

10.3.2
The CRC module includes:
Refer to the direct-page register summary in the Memory chapter of this data sheet for the absolute address
assignments for all CRC registers. This section refers to registers only by their names. A
Freescale-provided equate or header file is used to translate these names into the appropriate absolute
addresses.
10.3.2.1
10.3.2.2
Freescale Semiconductor
CRCH
Field
Reset
Reset
7–0
•
W
W
R
R
A 16-bit CRC result and seed register (CRCH:CRCL)
CRCH — This is the high byte of the 16-bit CRC register. A write to CRCH will load the high byte of the initial 16-bit
seed value directly into bits 15–8 of the shift register in the CRC generator. The CRC generator will then expect the
low byte of the seed value to be written to CRCL and loaded directly into bits 7–0 of the shift register. Once both seed
bytes written to CRCH:CRCL have been loaded into the CRC generator, and a byte of data has been written to
CRCL, the shift register will begin shifting. A read of CRCH will read bits 15–8 of the current CRC calculation result
directly out of the shift register in the CRC generator.
Bit 15
Register Description
Bit 7
CRC High Register (CRCH)
0
CRC Low Register (CRCL)
0
7
7
Offsets 4, 5, 6 and 7 are also mapped onto the CRCL register. This is an alias
only used on CF1Core (version 1 of ColdFire core) and must be ignored for
HCS08 cores. See
CF1Core
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
Bit 14
Bit 6
for more details.
0
0
6
6
Figure 10-2. CRC High Register (CRCH)
Figure 10-3. CRC High Register (CRCH)
Table 10-2. Register Field Descriptions
Section 10.4.2, “Programming Model Extension for
Bit 13
Bit 5
0
0
5
5
Bit 12
Bit 4
NOTE
0
0
4
4
Description
Bit 11
Bit 3
3
0
3
0
Cyclic Redundancy Check Generator (CRCV2)
Bit 10
Bit 2
0
0
2
2
Bit 9
Bit 1
0
0
1
1
Bit 8
Bit 0
0
0
0
0
10-3