upd70f3422gj-gae-qs-ax Renesas Electronics Corporation., upd70f3422gj-gae-qs-ax Datasheet - Page 648

• Manufacturer Part Number: upd70f3422gj-gae-qs-ax
• Description: 32-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

Chapter 19
648
Figure 19-10
Figure 19-9
R
D
(Control field)
(Data field or control field)
Note
Note
R
D
<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.
Data field
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.
CRC field
D: Dominant = 0
R: Recessive = 1
• The polynomial P(X) used to generate the 15-bit CRC sequence is
• Transmitting node:
• Receiving node:
Preliminary User’s Manual U17566EE1V2UM00
expressed as follows.
P(X) = X
Data 0
(8 bits)
15
MSB
+ X
14
+ X
→
10
Data field
CRC sequence
+ X
LSB
Transmits the CRC sequence calculated from the
data (before bit stuffing) in the start of frame,
arbitration field, control field, and data field.
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.
(15 bits)
CRC field
8
+ X
7
+ X
4
+ X
(8 bits)
Data 7
CRC delimiter
MSB
3
(1 bit)
+ 1
→
(ACK field)
(CRC field)
CAN Controller (CAN)
LSB