
GT-96100A Advanced Communication Controller
Revision 1.0
275
The GT-96100A uses the HE (Hash Expired) and M (Match) bits in the descriptor for reporting the packet filter-
ing status.
Table 282 describes the various reports and summarizes their meaning.
12.4
Ethernet Port
12.4.1 Network Interface
The Ethernet port interfaces directly to a MII (Media Independent Interface) PHY compliant with the IEEE stan-
dard (please refer to IEEE 802.3u Fast Ethernet standard for detailed interface and timing information). The MII
port has the following characteristics:
Capable of supporting both 10 Mbps and 100 Mbps data rates in half or full duplex modes.
Data and delimiters are synchronous to clock references.
Provides independent 4-bit wide transmit and receive paths.
Uses TTL signal levels.
Provides a simple management interface (common to all ports).
Capable of driving a limited length of shielded cable.
The port incorporates all the required digital circuitry to interface with a 100BaseTX, 100BaseT4, and
100BaseFX MII PHYs.
12.4.1.1 10/100 MII/RMII Compatible Interface
The port’s MAC (Media Access Control) logic supports connection to a 10Mbps or 100Mbps network.
The MII interface consists of a separate nibble-wide stream for both transmit and receive data. Data transfers are
clocked by the 25 MHz transmit and receive clocks in 100 Mbps operation, or by 2.5 MHz transmit and receive
clocks in 10 Mbps operation. The clock inputs are driven by the PHY, which controls the clock rate according to
the network connection speed.
The RMII interface consists of a separate 2bit-wide stream for both transmit and receive data. Data transfers are
clocked by the 50 MHz clock in both 100 Mbps and 10 Mbps operation. The clock input is driven by an external
source.
Table 282: Packet Filtering Status
HE
M
Conditio n
0
Hash Table No Hit
The address was not found in the Hash table, but Promiscuous Mode is
enabled
0
1
Hash Table Hit
Either by an address found in the Hash table and RD bit set
OR by an address that was not found in the Hash table, in case that
HDM bit is set
1
0
Hash Table Expired
The hopNumber expired before the address was found in the Hash table
11UnUsed