Module Operation
1242
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
FlexRay Module
If after the first double-cycle less than two valid startup frames are received within an even cycle, or less
than two valid startup frame pairs are received within a double-cycle, the startup attempt is aborted.
Nodes in this state need to see two valid startup frame pairs for two consecutive double-cycles each to be
allowed to leave STARTUP and enter NORMAL_OPERATION. Consequently, they leave startup at least
one double-cycle after the node that initiated the coldstart and only at the end of a cycle with an odd cycle
number.
26.2.6.8 NORMAL_ACTIVE State
As soon as the node that transmitted the first CAS symbol (resolving the potential access conflict and
entering STARTUP through the coldstart path) and one additional node have entered the
NORMAL_ACTIVE state, the startup phase for the cluster has finished. In the NORMAL_ACTIVE state, all
configured messages are scheduled for transmission. This includes all data frames as well as the sync
frames. Rate and offset measurement is started in all even cycles (even/odd cycle pairs required).
In NORMAL_ACTIVE state the communication controller supports regular communication functions:
•
The communication controller performs transmissions and reception on the FlexRay bus as configured
•
Clock synchronization is running
•
The host interface is operational
The communication controller exits from that state to:
•
HALT state by writing SUCC1.CMD(3-0) = 0110 (HALT command, at the end of the current cycle)
•
HALT state by writing SUCC1.CMD(3-0) = 0111 (FREEZE command, immediately)
•
HALT state due to change of the error state from ACTIVE to COMM_HALT
•
NORMAL_PASSIVE state due to change of the error state from ACTIVE to PASSIVE
•
READY state by writing SUCC1.CMD(3-0) = 0010 (READY command)
26.2.6.9 NORMAL_PASSIVE State
NORMAL_PASSIVE state is entered from NORMAL_ACTIVE state when the error state changes from
ACTIVE to PASSIVE.
In NORMAL_PASSIVE state, the node is able to receive all frames (node is fully synchronized and
performs clock synchronization). Contrary to the NORMAL_ACTIVE state, the node does not actively
participate in communication, that is, neither symbols nor frames are transmitted.
In NORMAL_PASSIVE state:
•
The communication controller performs reception on the FlexRay bus
•
The communication controller does not transmit any frames or symbols on the FlexRay bus
•
Clock synchronization is running
•
The host interface is operational
The communication controller exits from this state to
•
HALT state by writing SUCC1.CMD(3-0) = 0110 (HALT command, at the end of the current cycle)
•
HALT state by writing SUCC1.CMD(3-0) = 0111 (FREEZE command, immediately)
•
HALT state due to change of the error state from PASSIVE to COMM_HALT
•
NORMAL_ACTIVE state due to change of the error state from PASSIVE to ACTIVE. The transition
takes place when CCEV.PTAC(4-0) equals SUCC1.PTA(4-0) - 1.
•
To READY state by writing SUCC1.CMD(3-0) = 0010 (READY command)
26.2.6.10 HALT State
In this state all communication (reception and transmission) is stopped.
The communication controller enters this state:
•
By writing SUCC1.CMD(3-0) = 0110 (HALT command) while the communication controller is in
NORMAL_ACTIVE or NORMAL_PASSIVE state
