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Chapter 13 FlexRay Communication Controller (FLEXRAY)
MC9S12XF - Family Reference Manual, Rev.1.19
562
Freescale Semiconductor
Module Transitions
The module transitions that can be triggered by the FlexRay block are described in
Table 13-96. Each
transition will be triggered for certain message buffers when the related condition is fullled.
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 rst part of
Table 13-97, 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 rst 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 13-97.HL
MBCCSRn.LCKT:= 1
MBCCSRn.LCKS = 0 Application triggers message buffer lock.
HU
MBCCSRn.LCKS = 1 Application triggers message buffer unlock.
Table 13-96. 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
lter matches.
TX
slot start and
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 eld and message buffer status ags updated.
Interrupt ag 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.
Table 13-97. Single Transmit Message Buffer Transition Priorities
State
Priorities
Description
module vs. application
Idle, HLck
SA > HD
MA > HD
Slot Assigned > Message Buffer Disable
Message Available > Message Buffer Disable
CCMa
TX > HL
Transmission Start > Message Buffer Lock
Table 13-95. Single Transmit Message Buffer Application Transitions
Transition
Command
Condition
Description