NXP Semiconductors MPC5644A, Reference Manual, Page: 1551 / 1735

FlexRay Communication Controller (FlexRay)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 1551
For transmit message buffers, the application must follow the write access restrictions given in
Table 33-102 .
33.6.6 Individual message buffer functional description
The CC provides three basic types of individual message buffers:
1. Single transmit message buffers
2. Double transmit message buffers
3. Receive message buffers
Before an individual message buffer can be used, it must be configured by the application. After the initial
configuration, the message buffer can be reconfigured later. The set of the configuration data for individual
message buffers is given in
Section 33.6.3.4.1, Individual message buffer configuration data ”.
33.6.6.1 Individual message buffer configuration
The individual message buffer configuration consists of two steps.
1. The first step is the allocation of the required amount of memory for the FlexRay memory area.
2. The second step is the programming of the message buffer configuration registers, which is
described in this section.
33.6.6.1.1 Common configuration data
One part of the message buffer configuration data is common to all individual message buffers and the
receive shadow buffers. These data can only be set when the protocol is in the
POC:config state.
Table 33-102. Frame data write access constraints
Field Single buffered
Double buffered
Commit side Transmit side
DATA, MID, NMV POC:config or MB_DIS
or MB_LCK
POC:config or MB_DIS
or MB_LCK
POC:config or MB_DIS
Table 33-103. Frame Data field description
Field Description
DATA 0,
DATA 1,
...
DATA N-1
Message Data — Provides the message data received or to be transmitted.
For receive message buffer and receive FIFOs, this field provides the message data received for this
message buffer.
For transmit message buffers, the field provides the message data to be transmitted.
MID 0,
MID 1
Message Identifier — If the payload preamble bit PPI is set in the message buffer frame header, the
MID field holds the message ID of a dynamic frame located in the message buffer. The receive FIFO
filter uses the received message ID for message ID filtering.
NMV 0,
NMV 1,
...
NMV 11
Network Management Vector — If the payload preamble bit PPI is set in the message buffer frame
header, the network management vector field holds the network management vector of a static frame
located in the message buffer.
Note: The MID and NMV bytes replace the corresponding DATA bytes.