FlexRay Module (FLEXRAYV2)
MFR4300 Data Sheet, Rev. 1
Freescale Semiconductor
155
3.4.6.2.3
Message Buffer Transitions
Application Transitions
The application transitions can be triggered by the application using the commands described in
Table 3-92
. The application issues the commands by writing to the
Message Buffer Configuration,
Control, Status Registers (MBCCSRn)
. Only one command can be issued with one write access. Each
command is executed immediately. If the command is ignored, it must be issued again.
The enable and disable commands issued by writing ‘1’ to the trigger bit MBCCSRn.EDT. The transition
that will be triggered by each of these command depends on the current value of the status bit
MBCCSRn.EDS. If the command triggers the disable transition
HD
and the message buffer is in one of
the states
CCSa
,
HLckCCSa
,
CCMa
,
HLckCCMa, CCNf
,
HLckCCNf
, or
CCTx
, the disable transition
has no effect (command is ignored) and the message buffer state is not changed. No notification is given
to the application.
The lock and unlock commands issued by writing ‘1’ to the trigger bit MBCCSRn.LCKT. The transition
that will be triggered by each of these commands depends on the current value of the status bit
MBCCSRn.LCKS. If the command triggers the lock transition
HL
and the message buffer is in the state
CCTx,
the lock transition has no effect (command is ignored) and message buffer state is not changed. In
this case, the message buffer lock error flag LCK_EF in the
CHI Error Flag Register (CHIERFR)
is set.
CCSa
1
0
–
–
Slot Assigned
- Message buffer assigned to next static slot.
Ready for Null Frame transmission.
Locked and Slot Assigned
- Applications access to data, control,
and status.Message buffer assigned to next static slot
Null Frame Transmission
Header is used for null frame transmission.
Locked and Null Frame Transmission
- Applications access to
data, control, and status. Header is used for null frame transmission.
Message Available
- Message buffer is assigned to next slot and
cycle counter filter matches.
Locked and Message Available
- Applications access to data,
control, and status. Message buffer is assigned to next slot and cycle
counter filter matches.
Message Transmission
- Message buffer data transmit. Payload
data from buffer transmitted
Status Update
- Message buffer status update. Update of status
flags, the slot status field, and the header index.
HLckCCSa
1
1
MSG
–
CCNf
1
0
–
NF
HLckCCNf
1
1
MSG
NF
CCMa
1
0
–
CM
HLckCCMa
1
1
MSG
–
CCTx
1
0
–
TX
CCSu
1
0
–
TX
Table 3-92. Single Transmit Message Buffer Application Transitions
Transition
Command
Condition
Description
HE
HD
MBCCSRn.EDT:= 1
MBCCSRn.EDS = 0 Application triggers message buffer enable.
MBCCSRn.EDS = 1 Application triggers message buffer disable.
Table 3-91. Single Transmit Message Buffer State Description (Sheet 2 of 2)
State
MBCCSRn
Access Region
Description
EDS
LCKS
Appl.
Module