Datasheet

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5.0 Buffer Management (Continued)
DP83815
Table 5-3 Transmit Status Bit Definitions
27 OK Packet OK In the last descriptor in a packet, this bit indicates that the packet
was either sent or received successfully.
26-16 --- The usage of these bits differ in receive and transmit descriptors.
See below for details.
15-12 (reserved)
11-0 SIZE Descriptor Byte Count Set to the size in bytes of the data.
Bit Tag Description Usage
26 TXA Transmit Abort Transmission of this packet was aborted.
25 TFU Transmit FIFO
Underrun
Transmit FIFO was exhausted during the transmission of this
packet.
24 CRS Carrier Sense Lost Carrier was lost during the transmission of this packet. This
condition is not reported if TXCFG:CSI is set.
23 TD Transmit Deferred Transmission of this packet was deferred.
22 ED Excessive Deferral The length of deferral during the transmission of this packet was
excessive (> 3.2 ms), indicating transmission failure.
21 OWC Out of Window
Collision
The MAC encountered an "out of window" collision during the
transmission of this packet.
20 EC Excessive Collisions The number of collisions during the transmission of this packet
was excessive, indicating transmission failure.
If TXCFG register ECRETRY=0, this bit is set after 16 collisions.
If TXCFG register ECRETRY=1, this bit is set after 4 Excessive
Collision events (64 collisions).
19-16 CCNT Collision Count If TXCFG register ECRETRY=0, this field indicates the number of
collisions encountered during the transmission of this packet.
If TXCFG register ECRETRY=1,
CCNT[3:2] = Excessive Collisions (0-3)
CCNT[1] = Multiple Collisions
CCNT[0] = Single Collision
Note that Excessive Collisions indicate 16 attempts failed, while
multiple and single collisions indicate collisions in addition to any
excessive collisions. For example a collision count of 33 includes
2 Excessive Collisions and will also set the Single Collision bit.
Obsolete