HD64F2168 Datasheet, PDF (473/874 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer

14.11.4 Note on CRC Operation Circuit
Note that the sequence to transmit the CRC code differs between LSB-first transmission and
MSB-first transmission.
1. CRC code generation
After specifying the operation method, write data to CRCDIR in the sequence of (1) → (2) → (3) → (4).
7
0
CRCDIR
(1) → (2) → (3) → (4)
7
CRCDORH
CRCDORL
CRC code generation
0
(5)
(6)
2. Transmission data
(i) LSB-first transmission
CRC code
7
07
07
07
07
07
0
(5)
(6)
(4)
(3)
(2)
(1)
Output
(ii) MSB-first transmission
CRC code
Output
7
07
07
07
07
07
0
(1)
(2)
(3)
(4)
(5)
(6)
Figure 14.50 LSB-First and MSB-First Transmit Data
Rev. 3.00, 03/04, page 433 of 830