NXP Semiconductors MPC5644A, Reference Manual, Page: 1565 / 1735

FlexRay Communication Controller (FlexRay)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 1565
Module transitions
The module transitions that can be triggered by the CC are described in Table 33-113 . Each transition will
be triggered for certain message buffers when the related condition is fulfilled.
Transition priorities
The application can trigger only one transition at a time. There is no need to specify priorities among them.
As shown in Table 33-114 , the module transitions have a higher priority than the application transitions.
For all states except the CCRx state, a module transition and the application lock/unlock transition HL/HU
and can be executed at the same time. The result state is reached by first applying the module transition
and subsequently the application transition to the intermediately reached state. For example, if the message
buffer is in the buffer subscribed state CCBs and the module triggers the slot start transition SLS at the
same time as the application locks the message buffer by the HL transition, the intermediate state is CCRx
and the resulting state is locked buffer subscribed state HLckCCRx.
Table 33-112. Receive message buffer application transitions
Transition Host command Condition Description
HE FR_MBCCSRn[EDT] = 1 FR_MBCCSRn[EDS] = 0 Application triggers message buffer enable
HD FR_MBCCSRn[EDS] = 1 Application triggers message buffer disable
HL FR_MBCCSRn[LCKT] = 1 FR_MBCCSRn[LCKS] = 0 Application triggers message buffer lock
HU FR_MBCCSRn[LCKS] = 1 Application triggers message buffer unlock
Table 33-113. Receive message buffer module transitions
Transition Condition Description
BS Slot match and
CycleCounter match
Buffer Subscribed – The message buffer filter matches next slot and cycle
SLS Slot start Slot Start – Start of either Static Slot or Dynamic Slot
SNS Symbol window start
or
NIT start
Symbol Window or NIT Start – Start of either Symbol Window or NIT
SSS Slot start or
symbol window start
or
NIT start
Slot or Segment Start – Start of either Static Slot, Dynamic Slot, Symbol
Window, or NIT
SU Status updated Status Updated – Slot Status field, message buffer status flags, header index
updated; interrupt flag set
Table 33-114. Receive message buffer transition priorities
State Priorities Description
Module versus application
Idle BS > HD Buffer Subscribed > Message Buffer Disable