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Chapter 13 FlexRay Communication Controller (FLEXRAY)
MC9S12XF - Family Reference Manual, Rev.1.19
550
Freescale Semiconductor
For transmit message buffers assigned to the dynamic segment, the PLDLEN value must be less than or
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 eld in the frame header set to PLDLEN.
Table 13-84. 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 block 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 rst valid frame received on the FlexRay in the slot indicated by the CYCCNT eld.
For transmit message buffers, this is a control bit. The FlexRay block 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 rst valid frame received on the FlexRay bus in the slot indicated by the CYCCNT eld.
For transmit message buffers, the value of this bit is ignored. The FlexRay block 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 rst valid frame received on the FlexRay bus in the slot indicated by the CYCCNT eld.
For transmit message buffers, the value of this bit is ignored. The FlexRay block 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 rst valid frame received on the FlexRay bus in the slot indicated by the CYCCNT eld
For transmit message buffers, the value of this bit is ignored. The FlexRay block 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 eld provides the value of the Frame ID eld of the rst
valid frame received on the FlexRay bus in the slot indicated by the CYCCNT eld.
For transmit message buffers, this eld provides the value that will be transmitted in the Frame ID eld of the
FlexRay frame.
Note: For transmit message buffers, the application must program this eld to the same value as in the
(CHIERFR). The value of the FID eld will be ignored and replaced by the value provided in the
Message