Freescale Semiconductor FlexRay MFR4310 - Page 145

FlexRay Module (FLEXRAYV4)
MFR4310 Reference Manual, Rev. 2
Freescale Semiconductor 145
3.4.5.2.2 Data Field Offset Description
Data Field Offset Content
For a detailed description of the Data Field Offset, see Section 3.4.2.1.2, “Data Field Offset”.
Data Field Offset Access
The application shall program the Data Field Offset when configuring the message buffers in the
POC:config state or when the message buffer is disabled.
3.4.5.2.3 Slot Status Description
The slot status is a read-only structure for the application and a write-only structure for the FlexRay
module. The meaning and content of the slot status in the message buffer header field depends on the
message buffer type.
Receive Message Buffer and Receive FIFO Slot Status Description
This section describes the slot status structure for the individual receive message buffers and receive
FIFOs. The content of the slot status structure for receive message buffers depends on the message buffer
type and on the channel assignment for individual receive message buffers as given by Table 3-82.
CYCCNT Cycle Count
• For receive message buffer and receive FIFOs, this field provides the number of the communication cycle in
which the frame stored in this message buffer was received.
• For transmit message buffers, the value of this field is ignored. The FlexRay module overwrites this value with
the current cycle count value when it transmits the frame.
PLDLEN Payload Length in 16-Bit Units
• For receive message buffers and receive FIFOs, this field provides the value of the payload length field of the
first valid frame received on the FlexRay bus in the slot indicated by the FID field.
• For transmit message buffers assigned to the static segment, this value is ignored for the frame generation.
The FlexRay module uses the value in the PCR19.paylaod_length_static to set the value of the Payload length
field in the transmitted frame.
• For transmit message buffers assigned to the dynamic segment, this value is used to set the value of the
Payload length field in the transmitted frame.
Note: The value of this field is given in numbers of 16-bit units
HDCRC Header CRC
• For receive and FIFO message buffers, this field provides the value of the Header CRC of the received frame.
• For transmit message buffers, this field provides the Header CRC value as it was given by the application.The
FlexRay module transmits this value in the Header CRC field of the transmitted frame.
Table 3-81. Frame Header Field Descriptions (Continued)
Field Description