NXP Semiconductors MPC5644A, Reference Manual, Page: 1557 / 1735

FlexRay Communication Controller (FlexRay)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 1557
Module transitions
The module transitions that can be triggered by the CC are described in Table 33-108 . 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 the first part of Table 33-109 , the module transitions have a higher priority than the
application transitions. For all states except the CCMa state, both a lock/unlock transition HL/HD and a
module transition can be executed at the same time. The result state is reached by first applying the
application transition and subsequently the module transition to the intermediately reached state. For
example, if the message buffer is in the HLck state and the application unlocks the message buffer by the
HU transition and the module triggers the slot assigned transition SA, the intermediate state is Idle and the
resulting state is CCSa.
The priorities among the module transitions is given in the second part of Table 33-109 .
Table 33-107. Single transmit message buffer application transitions
Transition 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 33-108. Single transmit message buffer module transitions
Transition Condition Description
SA Slot match and
static slot
Slot Assigned – Message buffer is assigned to next static slot.
MA Slot match and
CycleCounter match
Message Available – Message buffer is assigned to next slot and cycle
counter filter matches.
TX Slot start and
FR_MBCCSRn[CMT] = 1
Transmission Slot Start – Slot Start and commit bit CMT is set. In case of
a dynamic slot, pLatestTx is not exceeded.
SU Status updated Status Updated – Slot Status field and message buffer status flags
updated. Interrupt flag set.
STS Static slot start Static Slot Start – Start of static slot.
DSS Dynamic slot start or
symbol window start or
NIT start
Dynamic Slot or Segment Start – Start of dynamic slot or symbol window
or NIT.
SSS Slot start or
symbol window start or
NIT start
Slot or Segment Start – Start of static slot or dynamic slot or symbol
window or NIT.