Datasheet

V850ES/JG3-H, V850ES/JH3-H CHAPTER 20 CAN CONTROLLER
R01UH0042EJ0500 Rev.5.00 Page 900 of 1513
Aug 12, 2011
<4> Data field
The data field contains the amount of data (byte units) set by the control field. Up to 8 units of data can be
set.
Figure 20-9. Data Field
R
D
Data 0
(8 bits)
MSB → LSB
Data 7
(8 bits)
MSB → LSB
Data field (CRC field)
(Control field)
Remark D: Dominant = 0
R: Recessive = 1
<5> CRC field
The CRC field is a 16-bit field that is used to check for errors in transmit data.
Figure 20-10. CRC Field
R
D
CRC sequence
CRC delimiter
(1 bit)
(15 bits)
CRC field (ACK field)
(Data field or control field)
Remark D: Dominant = 0
R: Recessive = 1
• The polynomial P(X) used to generate the 15-bit CRC sequence is expressed as follows.
P(X) = X
15
+ X
14
+ X
10
+ X
8
+ X
7
+ X
4
+ X
3
+ 1
• Transmitting node: Transmits the CRC sequence calculated from the data (before bit stuffing) in the
start of frame, arbitration field, control field, and data field.
• Receiving node: Compares the CRC sequence calculated using data bits that exclude the
stuffing bits in the receive data with the CRC sequence in the CRC field. If the
two CRC sequences do not match, the node issues an error frame.