NXP Semiconductors MPC5644A, Reference Manual, Page: 1544 / 1735

FlexRay Communication Controller (FlexRay)
MPC5644A Microcontroller Reference Manual, Rev. 6
1544 Freescale Semiconductor
will be ignored and replaced by the value provided in the Message Buffer Frame ID Registers
(FR_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 (FR_PCR19) . If this is not
fulfilled, the static payload length error flag SPL_EF in the CHI Error Flag Register (FR_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.
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
(FR_PCR24) . If this is not fulfilled, the dynamic payload length error flag DPL_EF in the CHI Error Flag
Register (FR_CHIERFR) is set when the message buffer is under transmission. A syntactically and
semantically correct dynamic frame is generated with PLDLEN payload words and the payload length
field in the frame header set to PLDLEN.
Table 33-95. Frame header field description (receive message buffer and receive FFO)
Field Description
R Reserved Bit — This is the value of the Reserved bit of the received frame stored in the message
buffer
PPI Payload Preamble Indicator — This is the value of the Payload Preamble Indicator of the received
frame stored in the message buffer.
NUF Null Frame Indicator — This is the value of the Null Frame Indicator of the received frame stored in
the message buffer.
SYF Sync Frame Indicator — This is the value of the Sync Frame Indicator of the received frame stored
in the message buffer.
SUF Startup Frame Indicator — This is the value of the Startup Frame Indicator of the received frame
stored in the message buffer.
FID Frame ID — This is the value of the Frame ID field of the received frame stored in the message buffer.
CYCCNT Cycle Count — This is the number of the communication cycle in which the frame stored in the
message buffer was received.
PLDLEN Payload Length — This is the value of the Payload Length field of the received frame stored in the
message buffer.
HDCRC Header CRC — This is the value of the Header CRC field of the received frame stored in the message
buffer.
Table 33-96. Frame header field description (transmit message buffer)
Field Description
R Reserved Bit — This bit is not used, the value of the Reserved bit is generated internally according to
FlexRay Communications System Protocol Specification, Version 2.1 Rev A.
PPI Payload Preamble Indicator — This bit provides the value of the Payload Preamble Indicator for the
frame transmitted from the message buffer.
NUF Null Frame Indicator — This bit is not used, the value of the Null Frame Indicator is generated
internally according to
FlexRay Communications System Protocol Specification, Version 2.1 Rev A.