1 receive status format, 1 receive status format -18, Receive status - first word – Cirrus Logic EP93xx User Manual
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DS785UM1
Copyright 2007 Cirrus Logic
1/10/100 Mbps Ethernet LAN Controller
EP93xx User’s Guide
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If both EOF and EOB bits are zero, the entry was made for a receive header threshold. This
indicates that there have been at least as many bytes transferred as specified in Receive
Header Length 1 or 2. These registers may be set to any threshold to provide an early
indication to the Host that a receive frame is in progress. The status will contain valid data in
the address match and hash table fields, but as the status is provided before end of frame is
reached, it will always indicate received without error.
If the EOF bit is zero and the EOB bit is set, the status indicates that the end of a receive
buffer has been reached before the end of the receive frame. If the receive buffers are much
smaller than the frame size, there may be many such statuses per frame.
When the EOF and EOB bits are both set, the status indicates the end of frame has been
transferred. The EOB is always set at this time to indicate that the MAC has finished
transferring to the buffer. The buffer is not necessarily full.
When a status event causes an interrupt, the interrupt pin will be activated after the status
has been transferred to the status queue.
9.2.3.1 Receive Status Format
Receive Status - First Word
Definition:
Receive Status, first word. Contains status information for the receiver
operation.
Bit Descriptions:
RSVD:
Reserved. Unknown During Read.
RFP:
Receive Frame Processed. The Receive Frame
Processed bit is always written as a “1” by the MAC when
the status is ready and it may be used by the Host to mark
its progress through the status queue. The Host may
alternatively use the RXStsQCurAdd to determine how
much of the status queue to process.
RWE:
Received Without Error. The Received Without Error bit
indicates that the frame was received without any of the
following error conditions: CRCerror, ExtraData, Runt, or
Receive Overrun.
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24
23
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RFP
RWE
EOF
EOB
RSVD
AM
RX_Err
OE
FE
Runt
EData
CRCE
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14
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12
11
10
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8
7
6
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4
3
2
1
0
CRCI
RSVD
HTI
RSVD