PXS20RM Datasheet, PDF (829/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

FlexRay Communication Controller
Table 26-106. Single Transmit Message Buffer State Description (continued)
State
CCSu
FR_MBCCSRn Access Region
EDS
LCKS
Appl.
Modul
e
Description
1
0
–
TX Status Update - Message buffer status update. Update of
status flags, the slot status field, and the header index.
26.6.6.2.3 Message Buffer Transitions
Application Transitions
The application transitions can be triggered by the application using the commands described in
Table 26-107. The application issues the commands by writing to the Message Buffer Configuration,
Control, Status Registers (FR_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.
Message Buffer Enable and Disable
The enable and disable commands issued by writing 1 to the trigger bit FR_MBCCSRn[EDT]. The
transition that will be triggered by each of these command depends on the current value of the status bit
FR_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.If the communication controller is started as a non-coldstart node and configured and
enabled message buffers in the POC config state for Slot 1, then the message buffer CAN NOT be disabled
in the INTEGRATION_LISTEN state by directly writing '1' to the EDT bit. To facilitate this, a FREEZE
command needs to be issued just before running the message buffer disable for slot 1. This should enable
the message buffer disable during the LISTEN states.
Message Buffer Lock and Unlock
The lock and unlock commands issued by writing 1 to the trigger bit FR_MBCCSRn[LCKT]. The
transition that will be triggered by each of these commands depends on the current value of the status bit
FR_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 (FR_CHIERFR)
is set.
Table 26-107. Single Transmit Message Buffer Application Transitions
Transition
HE
HD
HL
HU
Command
Condition
Description
FR_MBCCSRn[EDT]:= 1
FR_MBCCSRn[LCKT]:= 1
FR_MBCCSRn[EDS] = 0 Application triggers message buffer
enable.
FR_MBCCSRn[EDS] = 1 Application triggers message buffer
disable.
FR_MBCCSRn[LCKS] = 0 Application triggers message buffer
lock.
FR_MBCCSRn[LCKS] = 1 Application triggers message buffer
unlock.
Freescale Semiconductor
PXS20 Microcontroller Reference Manual, Rev. 1
26-117