dp83820 National Semiconductor Corporation, dp83820 Datasheet - Page 64
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dp83820
Manufacturer Part Number
dp83820
Description
10/100/1000 Mb/s Pci Ethernet Network Interface Controller
Manufacturer
National Semiconductor Corporation
Datasheet
1.DP83820.pdf
(87 pages)
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4.0 Register Set
4.2.27 Management Information Base Registers
The counters provide a set of statistics compliant with the
following management specifications: MIB II, Ether-like
MIB, and IEEE MIB. The values provided are accessed
through the various registers as shown below. All MIB
counters are cleared to 0 when read.
Due to cost and space limitations, the counter bit widths
provided in the DP83820 MIB are less than the bit widths
called for in the above specifications. It is assumed that
management agent software will maintain a set of fully
compliant statistic values ("software" counters), utilizing the
hardware counters to reduce the frequency at which these
006Ch
007Ch
0060h
0064h
0068h
0070h
0074h
0078h
0080h
0084h
0088h
offset
RXFrameTooLong
RXMsdPktErrors
RXSymbolErrors
RXPauseFrames
TXPauseFrames
RXBadOpcodes
RXErroredPkts
RXFCSErrors
TXSQEErrors
RXIRLErrors
RXFAErrors
tag
(Continued)
size
16
16
16
16
16
16
16
16
16
16
8
Table 4-3 MIB Registers
(MS bits)
warning
8
8
8
8
8
8
8
8
8
8
4
Packets received with errors. This counter is incremented for each
packet received with errors. This count includes packets which are
automatically rejected from the FIFO due to both wire errors and
FIFO overruns.
Packets received with frame check sequence errors. This counter is
incremented for each packet received with a Frame Check Sequence
error (bad CRC).
Note: For the MII interface, an FCS error is defined as a resulting
invalid CRC after CRS goes invalid and an even number of bytes
have been received.
Packets missed due to FIFO overruns. This counter is incremented
for each receive aborted due to data or status FIFO overruns
(insufficient buffer space).
Packets received with frame alignment errors. This counter is
incremented for each packet received with a Frame Check Sequence
error (bad CRC).
Note: For the MII interface, an FAE error is defined as a resulting
invalid CRC on the last full octet, and an odd number of nibbles have
been received (Dribble nibble condition with a bad CRC).
Packets received with one or more symbol errors. This counter is
incremented for each packet received with one or more symbol
errors detected.
Note: For the MII interface, a symbol error is indicated by the RX_ER
signal becoming active for one or more clocks while the RX_DV
signal is active (during valid data reception).
Packets received with length greater than 1518 bytes (too long
packets). This counter is incremented for each packet received with
greater than the 802.3 standard maximum length of 1518 bytes.
Packets received with In Range Length errors. This counter
increments for packets received with a MAC length/type value
between 64 and 1518 bytes, inclusive, that does not match the
number of bytes received. This counter also increments for packets
with a MAC length/type field of less than 64 bytes and more than 64
bytes received.
Packets received with a valid MAC control type and an opcode for a
function that is not supported by the device.
MAC control Pause frames received.
MAC control Pause frames transmitted.
Loss of collision heartbeat during transmission. This counter is
incremented when the collision heartbeat pulse is not detected by
the PMD after a transmission.
64
"software" counters must be updated. Sizes for specific
hardware statistic counters were chosen such that the
count values will not roll over in less than 30 ms if
incremented at the theoretical maximum rates described in
the above specifications.
theoretical maximum counter rates do not represent
realistic network traffic and events, the actual rollover rates
for the hardware counters are more likely to be on the order
of several seconds. The hardware counters are updated
automatically by the MAC on the occurrence of each event.
description
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