mfr4300 Freescale Semiconductor, Inc, mfr4300 Datasheet - Page 174

• Manufacturer Part Number: mfr4300
• Description: Flexray Communication Controllers
• Manufacturer: Freescale Semiconductor, Inc

FlexRay Module (FLEXRAYV2)
3.4.6.4.4
The application provides the message data through the commit side. The transmission itself is executed
from the transmit side. The transfer of the message data from the commit side to the transmit side is done
by the Internal Message Transfer, which is described in
To transmit a message over the FlexRay bus, the application writes the message data into the message
buffer data field of the commit side and sets the commit bit CMT in the
Control, Status Registers
in
As indicated by
commit bit CMT only if the transmit message buffer is in one of the states HDis, HDisLck, or HLck. The
application can change the state of a message buffer if it issues the appropriate commands given in
Table
3.4.6.4.5
The internal message transfer transfers the message data from the commit side to the transmit side. The
internal message transfer is implemented as the swapping of the content of the
Registers (MBIDXRn)
bit is cleared, the commit side interrupt flag MBIF is set, the transmit side CMT bit is set, and the transmit
side DVAL bit is cleared.
The conditions and the point in time when the internal message transfer is started are controlled by the
message buffer commit mode bit MCM in the
(MBCCSRn). The MCM bit configures the message buffer for either the streaming commit mode or the
immediate commit mode. A detailed description is given in
Commit
buffer enter enter one of the CCITx states. The internal message transfer is finished with the transition IE.
Streaming Commit Mode
The intention of the streaming commit mode is to ensure that each committed message is transmitted at
least once. The FlexRay module will not start the Internal Message Transfer for a message buffer as long
as the message data on the transmit side is not transmitted at least once.
The streaming commit mode is configured by clearing the message buffer commit mode bit MCM in the
Message Buffer Configuration, Control, Status Registers
In this mode, the internal message transfer from the commit side to the transmit side is started for a double
transmit message buffer when all of the following conditions are fulfilled
174
Section 3.4.3.1, “Individual Message
1. the commit side is in the Idle state
2. the commit site message data are valid, i.e. MBCCSR[2n].CMT = 1
3. the transmit side is in one of the states Idle, CCSa, or CCMa
4. the transmit side contains either no valid message data, i.e. MBCCSR[2n+1].CMT = 0 or
3-104. The state change is indicated through the MBCCSRn.EDS and MBCCSRn.LCKS status bits.
the message data were transmitted at least once, i.e. MBCCSR[2n+1].DVAL = 1
Mode. The Internal Message Transfer is triggered with the transition IS. Both sides of the message
Message Preparation
Internal Message Transfer
Table
3-102, the application shall write to the message buffer data field and change the
of the commit side and the transmit side. After the swapping, the commit side CMT
(MBCCSRn). The physical access to the message buffer data field is described
MFR4300 Data Sheet, Rev. 3
Buffers”.
Message Buffer Configuration, Control, Status Registers
Section 3.4.6.4.5, “Internal Message Transfer
(MBCCSRn).
Streaming Commit Mode
Message Buffer Configuration,
Message Buffer Index
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and
Immediate