CHAPTER 11 FCAN CONTROLLER
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User’s Manual U14492EJ3V0UD
<4> Data field
The data field contains the amount of data set by the control field. Up to 8 units of data can be set.
Remark
Data units in the data field are each 8 bits long and are ordered MSB first.
Figure 11-13. Data Field
R
D
Data
(8 bits)
Data
(8 bits)
Data field
(CRC field)
(Control field)
<5> CRC field
The CRC field is a 16-bit field that is used to check for errors in transmit data. It includes a 15-bit CRC
sequence and a 1-bit CRC delimiter.
Figure 11-14. CRC Field
R
D
CRC sequence
CRC delimiter
(1 bit)
(15 bits)
CRC field
(ACK field)
(Data field, control field)
• The polynomial P(X) used to generate the 15-bit CRC sequence is expressed as: X
15
+ X
14
+ X
10
+
X
8
+ X
7
+ X
4
+ X
3
+ 1
• Transmitting node: No bit stuffing in start of frame, arbitration field, control field, or data field: The
transferred CRC sequence is calculated entirely from basic data bits.
• Receiving node:
The CRC sequence calculated using data bits that exclude the stuffing bits in
the receive data is compared with the CRC sequence in the CRC field. If the
two CRC sequences do not match, the node is passed to an error frame.
Содержание V850E/IA1 mPD703116
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