Datasheet
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5.0 Buffer Management (Continued)
DP83815
Table 5-4 Receive Status Bit Definitions
5.1.2 Single Descriptor Packets
To represent a packet in a single descriptor, the MORE bit in the cmdsts field is set to 0.
Figure 5-1 Single Descriptor Packets
Bit Tag Description Usage
26 RXA Receive Aborted Set to 1 by DP83815 when the receive was aborted, the value of
this bit always equals RXO. Exists for backward compatibility.
25 RXO Receive Overrun Set to 1 by DP83815 to indicate that a receive overrun condition
occurred. RXA will also be set.
24-23 DEST Destination Class When the receive filter is enabled, these bits will indicate the
destination address class as follows:
00 - Packet was rejected
01 - Destination is a Unicast address
10 - Destination is a Multicast address
11 - Destination is a Broadcast address
If the Receive Filter is enabled, 00 indicates that the packet was
rejected. Normally packets that are rejected do not cause any bus
activity, nor do they consume receive descriptors. However, this
condition could occur if the packet is rejected by the Receive Filter
later in the packet than the receive drain threshold
(RXCFG:DRTH).
Note: The DEST bits may not represent a correct DA class for runt
packets received with less than 6 bytes.
22 LONG Too Long Packet
Received
If RXCFG:ALP=0, this flag indicates that the size of the receive
packet exceeded 1518 bytes.
If RXCFG:ALP=1, this flag indicates that the size of the receive
packet exceeded 2046 bytes.
21 RUNT Runt Packet Received The size of the receive packet was less than 64 bytes (inc. CRC).
20 ISE Invalid Symbol Error (100 Mb/s only) An invalid symbol was encountered during the
reception of this packet.
19 CRCE CRC Error The CRC appended to the end of this packet was invalid.
18 FAE Frame Alignment Error The packet did not contain an integral number of octets.
17 LBP Loopback Packet The packet is the result of a loopback transmission.
16 COL Collision Activity The receive packet had a collision during reception.
link
ptr
MAC hdr
netwk hdr
data
0
64
single descriptor / single fragment
Obsolete