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Chapter 13 FlexRay Communication Controller (FLEXRAY)
MC9S12XF - Family Reference Manual, Rev.1.19
Freescale Semiconductor
577
13.6.6.4.3
Message Buffer Transitions
Application Transitions
The application transitions that can be triggered by the application using the commands described in
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 notication. 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 notication 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 ag DBL_EF in 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
CCSa
1
0
–
Slot Assigned - Message buffer assigned to next static slot.
Ready for Null Frame transmission.
CCSaCCITx
1
0
–
TX
Slot Assigned and Internal Message Transfer - Message buffer
assigned to next static slot and Message Buffer Data transferred
from commit side to transmit side.
CCNf
1
0
–
TX
Null Frame Transmission
Header is used for null frame transmission.
CCNfCCITx
1
0
–
TX
Null Frame Transmission and Internal Message Transfer -
Header is used for null frame transmission and Message Buffer Data
transferred from commit side to transmit side.
CCMa
1
0
–
Message Available - Message buffer is assigned to next slot and
cycle counter lter matches.
CCMaCCITx
1
0
–
Message Available and Internal Message Transfer - Message
buffer is assigned to next slot and cycle counter lter matches and
Message Buffer Data transferred from commit side to transmit side.
CCTx
1
0
–
TX
Message Transmission - Message buffer data transmit. Payload
data from buffer transmitted
CCSu
1
0
–
SS
Status Update - Message buffer status update. Update of status
ags, the slot status eld, and the header index.
Note: The slot status eld of the commit side is updated too, even if
the application has locked the commit side.
Table 13-106. Double Transmit Message Buffer State Description (Transmit Side) (Sheet 2 of 2)
State
MBCCSRn
Access Region
Description
EDS
LCKS
Appl.
Module