Altera Low Latency 40-Gbps Ethernet MAC and PHY MegaCore Function User Manual
Page 138
link is functioning properly. The statistics registers check the size of frames, which includes the following
fields:
• Size of the destination address
• Size of the source address
• Size of the data
• Four bytes of CRC
The TX statistics counters module is a synthesis option. The statistics registers are counters that are
implemented inside the CSR. When you turn on the Enable TX statistics parameter in the Low Latency
40-100GbE parameter editor, the counters are implemented in the CSR. When you turn off the Enable
TX statistics parameter in the Low Latency 40-100GbE parameter editor, the counters are not
implemented in the CSR, and read access to the counters returns read data equal to 0.
Reading the value of a statistics register does not affect its value. A configuration register at offset 0x845
allows you to clear all of the TX statistics counters.
To ensure that the counters you read are consistent, you should issue a shadow request to create a
snapshot of all of the TX statistics registers, by setting bit [2] of the configuration register at offset 0x845.
Until you reset this bit, the counters continue to increment but the readable values remain constant.
Table 3-28: Transmit Side Statistics Registers
Address
Name-
Description
Access
0x800
CNTR_TX_
FRAGMENTS_LO
Number of transmitted frames less than 64 bytes and
reporting a CRC error (lower 32 bits)
RO
0x801
CNTR_TX_
FRAGMENTS_HI
Number of transmitted frames less than 64 bytes and
reporting a CRC error (upper 32 bits)
RO
0x802
CNTR_TX_
JABBERS_LO
Number of transmitted oversized frames reporting a CRC
error (lower 32 bits)
RO
0x803
CNTR_TX_
JABBERS_HI
Number of transmitted oversized frames reporting a CRC
error (upper 32 bits)
RO
0x804
CNTR_TX_FCS_LO
Number of transmitted packets with FCS errors. (lower 32
bits)
RO
0x805
CNTR_TX_FCS_HI
Number of transmitted packets with FCS errors. (upper 32
bits)
RO
0x806
CNTR_TX_CRCERR_
LO
Number of transmitted frames with a frame of length at
least 64 reporting a CRC error (lower 32 bits)
RO
0x807
CNTR_TX_CRCERR_
HI
Number of transmitted frames with a frame of length at
least 64 reporting a CRC error (upper 32 bits)
RO
0x808
CNTR_TX_MCAST_
DATA_ERR_LO
Number of errored multicast frames transmitted, excluding
control frames (lower 32 bits)
RO
UG-01172
2015.05.04
TX Statistics Registers
3-93
Functional Description
Altera Corporation