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1-Gigabit Ethernet MAC v8.5 User Guide
UG144 April 24, 2009
Chapter 5:
Using the Client Side Data Path
R
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Address Filter
If the optional Address Filter is included in the core, the MAC is able to reject frames that
do not contain a known address in their destination address field. If a frame is rejected, the
rx_data_valid
signal is not asserted for the duration of the frame. In addition, neither
rx_good_frame
or
rx_bad_frame
are asserted at the end of the frame. The statistics
vectors are still output with a valid pulse at the end of the rejected frame.
If the Address Filter is not in promiscuous mode, it will reject frames in which the
destination address does not meet any of the following criteria:
•
It is equal to the broadcast address defined in the
IEEE 802.3-2005
specification.
•
It is equal to the pause multicast address defined in the
IEEE 802.3-2005
specification.
•
The destination address field contains the pause frame MAC source address specified
in the Receiver Configuration Word 0 and Word 1.
•
It is equal to the MAC unicast address. When the optional Management Interface is
present, this is found in the unicast address configuration registers (
Table 8-8
and
Table 8-9, page 82
). If the Management Interface is not present the unicast address is
input on the
mac_unicast_address
input.
•
It matches any of the addresses stored in the MAC address table. The address table is
only present when the MAC contains the optional Management Interface and the core
was built with one or more address table entries.
Receiver Statistics Vector
The statistics for the frame received are contained within the
rx_statistics_vector
.
The vector is driven synchronously by the receiver clock,
gmii_rx_clk
, following frame
reception. The bit field definition for the vector is defined in
Table 5-2
.
All bit fields, with the exception of byte valid, are valid only when the
rx_statistics_valid
is asserted. This is illustrated in
Figure 5-5
. Byte valid is
significant on every
gmii_rx_clk
cycle.
Caution!
The statistic vectors in this release have been made compatible with the Tri-Mode
Ethernet MAC core. They are not backwards compatible with previous versions of the 1-Gigabit
Ethernet MAC core (see
Table 5-3
for Receiver Statistic Vector conversion details)
Figure 5-5:
Receiver Statistics Vector Timing
gmii_rx_clk
rx_statistics_vector[27:0]
rx_statistics_valid
