NEC V850E/RS1, User Manual, Page: 538 / 852

538
Chapter 16 FCAN Controller
User’s Manual U16702EE3V2UD00
16.2.5 Overload frame
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
Note: In this CAN controller, all reception frames can be loaded without outputting an overload frame
because of the high-speed internal processing.
Figure 16-16: Overload Frame
Remark: D: Dominant = 0
R: Recessive = 1
Node n
¼
node m
Table 16-8: Definition of Overload Frame Fields
No Name Bit Count Definition
<1> Overload flag 6 Outputs 6 dominant-level bits consecutively.
<2>
Overload flag from
other node
0 to 6
The node that received an overload flag in the interframe space outputs
an overload flag.
<3> Overload delimiter 8
Outputs 8 recessive-level bits consecutively.
If a dominant level is detected at the 8th bit, an overload frame is trans-
mitted from the next bit.
<4> Frame – Output following an end of frame, error delimiter, or overload delimiter.
<5>
Interframe space/
overload frame
– An interframe space or overload frame starts from here.
<1>
R
D
<2> <3>
6 bits 0 to 6 bits 8 bits
(<4>) (<5>)
Interframe space or overload frame
Overload delimiter
Overload flag (node n)
Overload flag (node m)
Frame
Overload frame
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