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FlexRay Module (FLEXRAYV2)
MFR4300 Data Sheet, Rev. 1
172
Freescale Semiconductor
3.4.6.4.3
Message Buffer Transitions
Application Transitions
The application transitions that can be triggered by the application using the commands described in
Table 3-104
. 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 can be issued on the transmit side only. Any enable or disable command
issued on the commit side will be ignored without notification. The transitions that will be triggered
depends on the value of the EDS bit. The enable and disable commands will affect both the commit side
and the transmit side at the same time. If the application triggers the disable transition
HD
while the
transmit side is in one of the states
CCSa
,
CCSaCCITx
,
CCNf
,
CCNfCCITx
,
CCMa
,
CCMaCCITx,
CCTx, or CCSu,
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 can be issued on the commit side only. Any lock or unlock command
issued on the transmit side will be ignored and the double transmit buffer lock error flag DBL_EF in the
CHI Error Flag Register (CHIERFR)
will be set. The transitions that will be triggered depends on the
current value of the LCKS bit. The lock and unlock commands will only affect the commit side. If the
application triggers the lock transition
HL
while the commit side is in the state
CCITx,
the message buffer
state will not be changed and the message buffer lock error flag LCK_EF in the
CHI Error Flag Register
(CHIERFR)
will be set.
Module Transitions
The module transitions that can be triggered by the FlexRay module are described in
Table 3-105
. The
transitions
C1
and
C2
apply to both sides of the message buffer and are applied at the same time. All other
FlexRay module transitions apply to the transmit side only.
CCSu
1
0
–
SS
Status Update
- Message buffer status update. Update of status
flags, the slot status field, and the header index.
Note:
The slot status field of the commit side is updated too, even if
the application has locked the commit side.
Table 3-104. Double Transmit Message Buffer Host Transitions
Transition
Host Command
Condition
Description
HE
HD
HL
HU
MBCCSR[2n+1].EDT:= 1
MBCCSR[2n+1].EDS = 0 Application triggers message buffer enable.
MBCCSR[2n+1].EDS = 1 Application triggers message buffer disable.
MBCCSR[2n].LCKS = 0 Application triggers message buffer lock.
MBCCSR[2n].LCKS = 1 Application triggers message buffer unlock.
MBCCSR[2n].LCKT:= 1
Table 3-103. Double Transmit Message Buffer State Description (Transmit Side) (Sheet 2 of 2)
State
MBCCSRn
Access Region
Description
EDS
LCKS
Appl.
Module