mc9s08ac32 Freescale Semiconductor, Inc, mc9s08ac32 Datasheet - Page 130

• Manufacturer Part Number: mc9s08ac32
• Description: Hcs08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 8 Cyclic Redundancy Check (S08CRCV1)
8.3
8.3.1
8.3.2
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.
8.3.2.1
130
CRCH
Field
(offset=0)
(offset=1)
Reset
7:0
CRCH
•
CRCL
Name
W
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.
Register Definition
Bit 15
Memory Map
Register Descriptions
CRC High Register (CRCH)
0
7
W
W
R
R
Bit 15
Bit 7
7
Bit 14
0
6
Bit 14
Bit 6
6
Figure 8-3. CRC High Register (CRCH)
Table 8-2. Register Field Descriptions
MC9S08AC60 Series Data Sheet, Rev. 2
Table 8-1. CRC Register Summary
Bit 13
0
5
Bit 13
Bit 5
5
Bit 12
0
4
Description
Bit 12
Bit 4
4
Bit 11
3
0
Bit 11
Bit 3
3
Bit 10
0
2
Bit 10
Bit 2
2
Freescale Semiconductor
Bit 9
Bit 9
Bit 1
0
1
1
Bit 8
Bit 8
Bit 0
0
0
0