
FlexRay Module (FLEXRAYV2)
MFR4300 Data Sheet, Rev. 1
164
Freescale Semiconductor
Module Transitions
The module transitions that can be triggered by the FlexRay module are described in
Table 3-98
. 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 3-99
, 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
.
3.4.6.3.2
Message Buffer Search
The FlexRay module starts a sequential search that checks all message buffers at the following protocol
related events:
slot start, in the static frame segment
minislot start, in the dynamic frame segment
NIT start
The filters that are used for the search are described in
Section 3.4.7.1, “Individual Message Buffer
Filtering
”.
Table 3-98. Receive Message Buffer Module Transitions
Transition
Condition
Description
BS
slot match and
CycleCounter match
slot start
Buffer Subscribed
- The message buffer filter matches next slot and cycle.
SLS
Slot Start
- Start of either Static Slot or Dynamic Slot.
SNS
symbol window start or
NIT start
slot start or
symbol window start or
NIT start
status updated
Symbol Window or NIT Start
- Start of either Symbol Window or NIT.
SSS
Slot or Segment Start
- Start of either Static Slot, Dynamic Slot, Symbol
Window, or NIT.
SU
Status Updated
- Slot Status field, message buffer status flags, header index
updated. Interrupt flag set.
Table 3-99. Receive Message Buffer Transition Priorities
State
Priorities
Description
module vs. application
Idle
HLck
CCRx
BS > HD
BS > HD
SSS > HL
Buffer Subscribed > Message Buffer Disable
Buffer Subscribed > Message Buffer Disable
Slot or Segment Start > Message Buffer Lock