DP83816-MAAP National Semiconductor, DP83816-MAAP Datasheet - Page 78

• Manufacturer Part Number: DP83816-MAAP
• Description: BOARD EVALUATION DP83816
• Manufacturer: National Semiconductor

Specifications of DP83816-MAAP

• Main Purpose: Interface, Ethernet
• Utilized Ic / Part: DP83816
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -

5.0 Buffer Management
26-16
15-12
19-16
11-0
Bit
27
26
25
24
23
22
21
20
CCNT
OWC
SIZE
CRS
TXA
TFU
Tag
OK
TD
ED
EC
---
Packet OK
Descriptor Byte Count Set to the size in bytes of the data.
Transmit Abort
Transmit FIFO
Underrun
Carrier Sense Lost
Transmit Deferred
Excessive Deferral
Out of Window
Collision
Excessive Collisions
Collision Count
(Continued)
Description
Table 5-3 Transmit Status Bit Definitions
In the last descriptor in a packet, this bit indicates that the packet
was either sent or received successfully.
The usage of these bits differ in receive and transmit descriptors.
See below for details.
(reserved)
Transmission of this packet was aborted.
Transmit FIFO was exhausted during the transmission of this
packet.
Carrier was lost during the transmission of this packet. This
condition is not reported if TXCFG:CSI is set.
Transmission of this packet was deferred.
The length of deferral during the transmission of this packet was
excessive (> 3.2 ms), indicating transmission failure.
The MAC encountered an "out of window" collision during the
transmission of this packet.
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).
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.
78
Usage
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