Can Protocol; Frame Format - NEC V850E/Dx3 Preliminary User's Manual

CAN Controller (CAN)
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19.2 CAN Protocol

CAN (Controller Area Network) is a high-speed multiplex communication
protocol for real-time communication in automotive applications (class C). CAN
is prescribed by ISO 11898. For details, refer to the ISO 11898 specifications.
The CAN specification is generally divided into two layers: a physical layer and
a data link layer. In turn, the data link layer includes logical link and medium
access control. The composition of these layers is illustrated below.
·
Logical link control (LLC)
Data link
layer Note
·
Medium access control (MAC)
Physical layer
Figure 19-2 Composition of layers
Note CAN Controller specification

19.2.1 Frame format

(1) Standard format frame
• The standard format frame uses 11-bit identifiers, which means that it can
handle up to 2,048 messages.
(2) Extended format frame
• The extended format frame uses 29-bit (11 bits + 18 bits) identifiers, which
increases the number of messages that can be handled to 2,048 × 2
messages.
• An extended format frame is set when "recessive level" (CMOS level of "1")
is set for both the SRR and IDE bits in the arbitration field.
Preliminary User's Manual U17566EE1V2UM00
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Acceptance filtering
·
Overload report
·
Recovery management
·
Data capsuled/not capsuled
·
Frame coding (stuffing/no stuffing)
·
Medium access management
·
Error detection
·
Error report
·
Acknowledgement
·
Seriated/not seriated
Prescription of signal level and bit description
Chapter 19
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