FlexRay Communication Controller (FLEXRAY)
22-88
Freescale Semiconductor
PXR40 Microcontroller Reference Manual, Rev. 1
Figure 22-111. Frame Header Structure (Transmit Message Buffer for Key Slot)
Frame Header Access
The frame header is located in the flexray memory. To ensure data consistency, the application must follow
the write access scheme described below.
For receive message buffers, receive shadow buffers, and receive FIFOs, the application must not write to
the frame header field.
For transmit message buffers, the application must follow the write access restrictions given in
. This table shows the condition under which the application can write to the frame header
entries without corrupting the FlexRay message transmission.
Frame Header Checks
not all fields in the message buffer frame header are used
for transmission. Some fields in the message buffer frame header are ignored, some are used for
transmission, and some of them are checked for correct values. All checks that will be performed are
described below.
For message buffers assigned to the key slot, no checks will be performed.
The value of the FID field must be equal to the value of the corresponding
. If the controller detects a mismatch while transmitting the frame header, it will set
the frame ID error flag FID_EF in the
CHI Error Flag Register (CHIERFR)
will be ignored and replaced by the value provided in the
Message Buffer Frame ID Registers (MBFIDRn)
.
For transmit message buffers assigned to the
static
segment, the PLDLEN value must be equal to the value
of the payload_length_static field in the
Protocol Configuration Register 19 (PCR19)
fulfilled, the static payload length error flag SPL_EF in the
CHI Error Flag Register (CHIERFR)
is set
when the message buffer is under transmission. A syntactically and semantically correct frame is generated
with payload_length_static payload words and the payload length field in the transmitted frame header set
to payload_length_static.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0x0
R
PPI
NUF
SYF
SUF
FID
0x2
CYCCNT
PLDLEN
0x4
HDCRC
= not used
Table 22-84. Frame Header Write Access Constraints (Transmit Message Buffer)
Field
Single Buffered
Double Buffered
Static
Segment
Dynamic
Segment
Static Segment
Dynamic Segment
Commit Side
Transmit Side
Commit Side
Transmit Side
FID
POC:config
or MB_DIS
PPI,
PLDLEN,
HDCRC
POC:config
or MB_DIS or
MB_LCK
MB_LCK
Summary of Contents for PXR4030
Page 1: ...PXR40 Microcontroller Reference Manual Devices Supported PXR4030 PXR4040 PXR40RM Rev 1 06 2011...
Page 30: ...PXR40 Microcontroller Reference Manual Rev 1 Freescale Semiconductor xxx...
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Page 66: ...Memory Map PXR40 Microcontroller Reference Manual Rev 1 2 4 Freescale Semiconductor...
Page 120: ...Signal Descriptions 3 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Page 860: ...FlexCAN Module 24 50 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
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