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Communication Processor Module
L—Last in Frame
The Ethernet controller sets this bit when this buffer is the last one in a frame. If the end of
a frame is reached or an error is received, one or more of the CL, OV, CR, SH, NO, and LG
bits are set. The SCCx Ethernet controller writes the number of frame octets to the DATA
LENGTH field.
0 = The buffer is not the last one in a frame.
1 = The buffer is the last one in a frame.
F—First in Frame
The SCCx Ethernet controller sets this bit when this buffer is the first one in a frame.
0 = The buffer is not the first one in a frame.
1 = The buffer is the first one in a frame.
M—Miss
The SCCx Ethernet controller sets this bit for frames that are accepted in promiscuous
mode, but are flagged as a "miss" by the internal address recognition. Thus, while in
promiscuous mode, you can use this bit to determine whether the frame is destined to this
station. This bit is valid only if the L bit is set.
0 = The frame is received because of an address recognition hit.
1 = The frame is received because of promiscuous mode.
LG—RX Frame Length Violation
This bit indicates that a frame length greater than the maximum defined for this channel has
been recognized. Only the maximum-allowed number of bytes is written to the data buffer.
NO—RX Nonoctet Aligned Frame
This bit indicates that a frame containing a number of bits not divisible by eight is received.
Also, the CRC check that occurs at the preceding byte boundary has generated an error.
SH—Short Frame
This bit indicates that a frame length less than the minimum defined for this channel has
been recognized. This can only happen if the RSH bit is set in the PSMR–SCC Ethernet.
CR—RX CRC Error
This bit indicates that this frame contains a CRC error.
OV—Overrun
This bit indicates that a receiver overrun has occurred during frame reception.
CL—Collision
This bit indicates that this frame is closed because a collision has occurred during frame
reception. This bit is only set if a late collision occurs or if the RSH bit is enabled in the
PSMR–SCC Ethernet. Late collisions are better defined in the LCW bit of the same register.
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MPC823e REFERENCE MANUAL
MOTOROLA
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