Protocol; Frame Format - NEC Renesas V850/SC1 User Manual

19.10 Protocol

CAN (Controller Area Network) is a high-speed multiplex communication protocol for real-time communication in
automotive applications (class C). CAN is prescribed in 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 control and medium access control. The composition of these layers is illustrated
below.
Higher
Data link
layer
Note
Lower Physical layer
Note CAN controller specification

19.10.1 Frame format

(1) Standard format frame
In this format 2048 different identifiers can be set.
• The standard format frame uses 11-bit identifiers, which means that it can handle up to 2048 messages.
(2) Extended format frame
This format is used to set the identifiers of approx. 5.3 million types.
• The extended format frame uses 29-bit (11 bits + 18 bits) identifiers which increases the number of
messages that can be handled to 2048 × 2
• Extended format frame is set when "recessive: logical level 1" is set for both the SRR and IDE bits in the
arbitration field.
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CHAPTER 19 FCAN CONTROLLER (V850/SC3)
Figure 19-10. Composition of Layers
·
Logical link control (LLC)
·
Medium access control (MAC)
18
User's Manual U15109EJ3V0UD
For details, refer to the ISO 11898
·
Acceptance filtering
·
Overload report
·
Recovery management
·
Data capsuled/not capsuled
·
Frame coding (stuffing/not stuffing)
·
Medium access management
·
Error detection
·
Error report
·
Acknowledgement
·
Seriated/not seriated
Prescription of signal level and bit description
messages.