Operation - Renesas RX100 Series User Manual

RX13T Group
25.3

Operation

The CRC calculator generates CRC codes for use in LSB first or MSB first transfer.
The following shows examples of generating the CRC code for input data (F0h) using the 16-bit CRC generating
16 12
polynomial (X + X + X
before CRC calculation.
When an 8-bit CRC (with the polynomial X
lower-order byte of the CRCDOR register.
1. Write 83h to the CRC control register (CRCCR)
CRCCR
7
1 0 0 0 0
2. Write F0h to the CRC data input register (CRCDIR)
CRCDIR
7
1 1 1 1 0
3. Read the calculation result in the CRC data output register (CRCDOR)
CRC code = F78Fh
4. 8-bit serial transmission (LSB first)
7
1 1 1 1 0
F
Figure 25.2 LSB First Data Transmission
1. Write 87h to the CRC control register (CRCCR)
CRCCR
7
1 0 0 0 0
2. Write F0h to the CRC data input register (CRCDIR)
CRCDIR
7
1 1 1 1 0
3. Read the calculation result in the CRC data output register (CRCDOR)
CRC code = EF1Fh
4. 8-bit serial transmission (MSB first)
7
Output
1 1
Figure 25.3 MSB First Data Transmission
R01UH0822EJ0100 Rev.1.00
Jul 31, 2019
5
+ 1). In these examples, the value of the CRC data output register (CRCDOR) is cleared
8 2
+ X + X + 1) is in use, the valid bits of the CRC code are obtained in the
CRCDOR
15
0
0 1 1 0
Clear CRCDOR
CRCDOR
15
0
0 0 0 1
CRC code generation
CRC code
0 7
1 1 1 1 0 0 0
7 8
CRCDOR
15
0
1 1 1 0
Clear CRCDOR
CRCDOR
15
0
0 0 0 1
CRC code generation
Data
0
1 1 0 0 0 0
F 0
0 0 0 0 0 0
1 1 1 0 1 1
0 7
1 1 1 1 1 1
F
0 0 0 0 0 0
1 1 0 1 1 1
7
1 1 1 0 1 1 1
E F
25. CRC Calculator (CRC)
8 7
0 0 0 0 0 0
8 7
1 1 0 0 0 1
Data
0
1 1 0 0 0 0
F 0
8 7
0 0 0 0 0 0
8 7
1 0 0 0 1 1
CRC code
0 7
1 0 0 0 1 1
1
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0
0 0 0
0
1 1 1
Output
0
0 0 0
0
1 1 1
0
1 1 1
F