Freescale Semiconductor FlexRay MFR4310 - Figure 3-6. Message Buffer Segment Size and Utilization Register (MBSSUTR); Table 3-13. MBDSR Field Descriptions; Table 3-14. MBSSUTR Field Descriptions

FlexRay Module (FLEXRAYV4)
MFR4310 Reference Manual, Rev. 2
76 Freescale Semiconductor
This register defines the size of the message buffer data section for the two message buffer segments in a
number of two-byte entities.
The FlexRay module provides two independent segments for the individual message buffers. All
individual message buffers within one segment have to have the same size for the message buffer data
section. This size can be different for the two message buffer segments.
3.3.2.7 Message Buffer Segment Size and Utilization Register (MBSSUTR)
This register is used to define the last individual message buffer that belongs to the first message buffer
segment and the number of the last used individual message buffer.
Table 3-13. MBDSR Field Descriptions
Field Description
14–8
MBSEG2DS
Message Buffer Segment 2 Data Size — The field defines the size of the message buffer data section in
two-byte entities for message buffers within the second message buffer segment.
6–0
MBSEG1DS
Message Buffer Segment 1 Data Size — The field defines the size of the message buffer data section in
two-byte entities for message buffers within the first message buffer segment.
0x000E Write: POC:config
1514131211109876543210
R0
LAST_MB_SEG1
0
LAST_MB_UTIL
W
Reset0111111101111111
Figure 3-6. Message Buffer Segment Size and Utilization Register (MBSSUTR)
Table 3-14. MBSSUTR Field Descriptions
Field Description
14–8
LAST_MB_SEG1
Last Message Buffer In Segment 1 — This field defines the message buffer number of the last individual
message buffer that is assigned to the first message buffer segment. The individual message buffers in the
first segment correspond to the message buffer control registers MBCCSRn, MBCCFRn, MBFIDRn, and
MBIDXRn with n less than or equaling LAST_MB_SEG1. The first message buffer segment contains
LAST_MB_SEG1+1 individual message buffers.
Note: The first message buffer segment contains at least one individual message buffer.
The individual message buffers in the second message buffer segment correspond to the message buffer
control registers MBCCSRn, MBCCFRn, MBFIDRn, MBIDXRn with LAST_MB_SEG1 < n < 128.
Note: If LAST_MB_SEG1 equals 127 all individual message buffers belong to the first message buffer
segment and the second message buffer segment is empty.
6–0
LAST_MB_UTIL
Last Message Buffer Utilized — This field defines the message buffer number of last utilized individual
message buffer. The message buffer search engine examines all individual message buffer with a message
buffer number n less than or equaling LAST_MB_UTIL.
Note: If LAST_MB_UTIL equals LAST_MB_SEG1 all individual message buffers belong to the first
message buffer segment and the second message buffer segment is empty.