FlexRay Module (FLEXRAYV4)
MFR4310 Reference Manual, Rev. 2
144 Freescale Semiconductor
For transmit message buffers assigned to the dynamic segment, the PLDLEN value must be less than or
equal to the value of the max_payload_length_dynamic field in the Protocol Configuration Register 24
(PCR24). If this is not fulfilled, the dynamic payload length error flag DPL_EF in the CHI Error Flag
Register (CHIERFR) is set when the message buffer is under transmission. The PE generates a
syntactically and semantically correct dynamic frame with PLDLEN payload words and the payload
length field in the frame header set to PLDLEN.
Table 3-81. Frame Header Field Descriptions
Field Description
R* Reserved Bit — This bit corresponds to the Reserved bit in the FlexRay frame header.
• For receive and FIFO message buffers, this is a status bit and represents the value of the Reserved bit in the
frame received on the FlexRay bus in the corresponding slot.
• For transmit message buffers, this is a control bit. The FlexRay module transmits this within the frame header.
Note: For protocol compliant operation, this control bit must be set to 0 for transmit message buffers.
PPI Payload Preamble Indicator — This bit corresponds to the Payload Preamble Indicator in the FlexRay frame
header.
• For receive and FIFO message buffers, this is a status bit and represents the value of the Payload Preamble
Indicator of the first valid frame received on the FlexRay in the slot indicated by the CYCCNT field.
• For transmit message buffers, this is a control bit. The FlexRay module uses this value to set the Payload
Preamble Indicator in the frame header of the frame to transmit.
0 No network management vector or message ID in frame payload data
1 Static Segment: Frame payload data contains network management vector
Dynamic Segment: Frame payload data contains message ID
NUF Null Frame Indicator — This bit corresponds to the Null Frame Indicator in the FlexRay frame header.
• For receive message buffers and receive FIFOs, this is a status bit and represents the value of the Null Frame
Indicator of the first valid frame received on the FlexRay bus in the slot indicated by the CYCCNT field.
• For transmit message buffers, the value of this bit is ignored. The FlexRay module determines internally
whether a null frame or non-null frame must be transmitted and sets the Null Frame Indicator accordingly.
0 Null frame received
1 Normal frame received
SYF Sync Frame Indicator — This bit corresponds to the Sync Frame Indicator in the FlexRay frame header.
• For receive message buffers and receive FIFOs, this is a status bit and represents the value of the Sync Frame
Indicator of the first valid frame received on the FlexRay bus in the slot indicated by the CYCCNT field.
• For transmit message buffers, the value of this bit is ignored. The FlexRay module determines internally
whether a sync frame must be transmitted and sets the Sync Frame Indicator accordingly.
SUF Startup Frame Indicator — This bit corresponds to the Startup Frame Indicator in the FlexRay frame header.
• For receive message buffers and receive FIFOs, this is a status bit and represents the value of the Startup
Frame Indicator of the first valid frame received on the FlexRay bus in the slot indicated by the CYCCNT field
• For transmit message buffers, the value of this bit is ignored. The FlexRay module determines internally
whether a startup frame must be transmitted and sets the Startup Frame Indicator accordingly.
FID Frame ID
• For receive message buffers and receive FIFOs, this field provides the value of the Frame ID field of the first
valid frame received on the FlexRay bus in the slot indicated by the CYCCNT field.
• For transmit message buffers, this field provides the value transmitted in the Frame ID field of the FlexRay
frame.
Note: For transmit message buffers, the application must program this field to the same value as in the
corresponding Message Buffer Frame ID Registers (MBFIDRn). If the FlexRay module detects a mismatch
while transmitting the frame header, it sets the frame ID error flag FID_EF in the CHI Error Flag Register
(CHIERFR). The value of the FID field is ignored and replaced by the value provided in the
Message Buffer
Frame ID Registers (MBFIDRn).
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