Renesas RX Series User Manual

R01UH0823EJ0100 Rev.1.00 Page 1416 of 1823
Jul 31, 2019
RX23W Group 39. CRC Calculator (CRC)
39.3 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
polynomial (X
16
+ X
12
+ X
5
+ 1). In these examples, the value of the CRC data output register (CRCDOR) is cleared
before CRC calculation.
When an 8-bit CRC (with the polynomial X
8
+ X
2
+ X + 1) is in use, the valid bits of the CRC code are obtained in the
lower-order byte of the CRCDOR register.
Figure 39.2 LSB First Data Transmission
Figure 39.3 MSB First Data Transmission
CRCDORCRCCR
Clear CRCDOR
1
7
00000
0
7
0
15
0
1100000000
CRCDIR
CRC code generation
111100 00
CRC code
Output
Data
7
7
7FFF08
00
111101 11 100011 1111110000
2. Write F0h to the CRC data input register (CRCDIR)
3. Read the calculation result in the CRC data output register (CRCDOR)
CRC code = F78Fh
4. 8-bit serial transmission (LSB first)
1. Write 83h to the CRC control register (CRCCR)
000000 00
CRCDOR
15
0
111101 11
10 00 1 1 11
78
78
70
CRCDORCRCCR
Clear CRCDOR
1
7
00001
0
7
0
15
0
1100000000
CRCDIR
CRC code generation
111100 00
CRC code
Output
Data
7
7
0FF1FE
0
0
111100 00 111011 1100011111
2. Write F0h to the CRC data input register (CRCDIR)
3. Read the calculation result in the CRC data output register (CRCDOR)
CRC code = EF1Fh
4. 8-bit serial transmission (MSB first)
1. Write 87h to the CRC control register (CRCCR)
000000 00
CRCDOR
15
0
111011 11
000111 11
78
78
70

Renesas RX Series Specifications

General

Brand	Renesas
Model	RX Series
Category	Microcontrollers
Language	English