NEC UPD703116 User Manual page 532

<8> Interframe space
The interframe space is inserted after the data frame, remote frame, error frame, and overload frame
to separate one frame from the next one.
• Error active node
When the bus is idle, transmit enable mode is set for each node. Transmission then starts from a
node that has received a transmit request.
If the node is an error active node, the interframe space is composed of a 3- or 2-bit intermission
field and bus idle field.
• Error passive node
After an 8-bit bus idle field, transmit enable mode is set. Receive mode is set if a transmission
starts from a different node in bus idle mode.
The error passive node is composed of an intermission field, suspend transmission field, and bus
idle field.
(a) Error active
R
D
(b) Error passive
(Frame)
R
D
• Bit length of intermission
When transmission is pending, transmission is resumed after a 3-bit intermission.
When receiving, the receive operation starts after only two bits.
• Bus idle
This mode is set when no nodes are using any buses.
• Suspend transmission
This is an 8-bit recessive (R) field that is transmitted from a node that is in error passive mode.
532
CHAPTER 11 FCAN CONTROLLER
Figure 11-18. Interframe Space
(Frame) Interframe space
Intermission
(3 or 2 bits)
Interframe space
Intermission Suspend transmission
(3 or 2 bits)
User's Manual U14492EJ5V0UD
(Frame)
Bus idle
(0 or more bits)
Bus idle
(8 bits) (0 or more bits)
(Frame)