Cirrus Logic EP93xx - Manual (Page 334)

9-32 DS785UM1
Copyright 2007 Cirrus Logic
1/10/100 Mbps Ethernet LAN Controller
EP93xx User’s Guide
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9.2.3.11 Transmit Status Format
Only one Transmit Status entry is posted for each transmit frame, regardless of the number of
transmit descriptors that are used to describe the frame.
Transmit Status
Definition:
Transmit Status. Contains the status information for the transmitter operation.
Bit Descriptions:
TxFP: Transmit Frame Processed. The Transmit 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.
TxWE: Transmitted Without Error. The transmitted Without Error
bit is set when a frame is successfully transmitted without
errors.
FA: Frame Abort. When a frame has been terminated by the
Host with an Abort Frame command, in the transmit
descriptor, the Frame Abort status bit is set.
LCRS: Loss of CRS. The Loss of CRS bit is set when a frame is
transmitted and the MII CRS signal is not asserted at the
end of preamble.
RSVD: Reserved. Unknown During Read.
OW: Out of Window. The Out of Window bit indicates that a
collision was detected after the transmission of more than
60 bytes (from the start of preamble).
TxU: Transmit Underrun. TxUnderrun is set when a frame fails
to be transmitted because of an excessive bus latency
starving the transmitter.
EColl: Excess Collisions. The excessive collision bit is set when
the frame failed to transmit due to excessive collisions.
This may either be due to one or sixteen collisions
dependent on the OneColl bit in the transmit descriptor.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
TxFP TxWE FA LCRS RSVD OW TxU EColl RSVD NColl
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
RSVD TBI