C8051F850-B-GM Datasheet, PDF (132/290 Pages) Silicon Laboratories – Low-Cost 8-bit MCU Family with up to 8 kB of Flash

C8051F85x/86x
18.6. CRC Control Registers
Register 18.1. CRC0CN: CRC0 Control
Bit
7
Name
6
5
Reserved
4
3
2
1
0
CRCINIT CRCVAL Reserved CRCPNT
Type
Reset
0
R
0
0
RW
RW
R
RW
1
0
0
0
0
SFR Address: 0xCE
Table 18.2. CRC0CN Register Bit Descriptions
Bit
Name
7:4
Reserved Must write reset value.
Function
3
CRCINIT CRC Result Initialization Bit.
Writing a 1 to this bit initializes the entire CRC result based on CRCVAL.
2
CRCVAL CRC Set Value Initialization Bit.
This bit selects the set value of the CRC result.
0: CRC result is set to 0x0000 on write of 1 to CRCINIT.
1: CRC result is set to 0xFFFF on write of 1 to CRCINIT.
1
Reserved Must write reset value.
0
CRCPNT CRC Result Pointer.
Specifies the byte of the CRC result to be read/written on the next access to CRC0DAT.
This bit will automatically toggle upon each read or write.
0: CRC0DAT accesses bits 7-0 of the 16-bit CRC result.
1: CRC0DAT accesses bits 15-8 of the 16-bit CRC result.
Note: Upon initiation of an automatic CRC calculation, the three cycles following a write to CRC0CN that initiate a CRC
operation must only contain instructions which execute in the same number of cycles as the number of bytes in the
instruction. An example of such an instruction is a 3-byte MOV that targets the CRC0FLIP register. When programming
in C, the dummy value written to CRC0FLIP should be a non-zero value to prevent the compiler from generating a 2-
byte MOV instruction.
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