Overload Frame - NEC V850ES/F 3-L Series User Manual

Chapter 18

18.2.5 Overload frame

Note
Figure 18-16
Note
Table 18-8
No Name
<1> Overload flag
Overload flag from other node
<2>
Overload delimiter
<3>
Frame
<4>
Interframe space/overload
<5>
frame
540
An overload frame is transmitted under the following conditions.
• When the receiving node has not completed the reception operation
• If a dominant level is detected at the first two bits during intermission
• If a dominant level is detected at the last bit (7th bit) of the end of frame or at
the last bit (8th bit) of the error delimiter/overload delimiter
The CAN is internally fast enough to process all received frames not
generating overload frames.
R
D
(<4>) <1>
6 bits
Overload frame
D: Dominant = 0
R: Recessive = 1
Definition of overload frame fields
Bit count Definition
6
0 to 6
8
–
–
User's Manual U18743EE1V2UM00
Overload frame
<2> <3> (<5>)
0 to 6 bits 8 bits
Outputs 6 dominant-level bits consecutively.
The node that received an overload flag in the interframe
space outputs an overload flag.
Outputs 8 recessive-level bits consecutively.
If a dominant level is detected at the 8th bit, an overload
frame is transmitted from the next bit.
Output following an end of frame, error delimiter, or overload
delimiter.
An interframe space or overload frame starts from here.
CAN Controller (CAN)
Interframe space or overload frame
Overload delimiter
Overload flag
Overload flag
Frame