TNETX15VE Datasheet, PDF (7/113 Pages) Texas Instruments – VLAN-ENGINE ADDRESS-LOOKUP DEVICE

TNETX15VE
VLAN-ENGINE ADDRESS-LOOKUP DEVICE
Terminal Functions
SPWS028B – APRIL 1997 – REVISED SEPTEMBER 1997
EAM interface
TERMINAL
NAME
NO.
EAM15†
106
EAM14
105
EAM13
104
EAM12
103
EAM11
102
EAM10
101
EAM9
99
EAM8
98
EAM7
97
EAM6
96
EAM5
95
EAM4
94
EAM3
93
EAM2
91
EAM1
90
EAM0‡
89
† _{Most-significant bit}
‡ _{Least-significant bit}
I/O
DESCRIPTION
External address match single-/multiple-port routing code select. When EAM15 is high, the EAM-interface
terminals contain a single-port routing code. When EAM15 is low, the EAM-interface terminals contain a
multiple-port routing code (VLAN).
External address match port routing code select. When EAM15 is high, the EAM14–EAM0 terminals are
placed in the single-port mode. In this mode EAM14–EAM0 terminals encode a single port to which the
frame is routed.
EAM14–EAM5 are don’t-care bits and are set to 0. The single-port codes (EAM15–EAM0 terminals) are
shown in the following:
TNETX3150/TNETX3150A
EAM15–EAM0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Port 00 (uplink)
1000000000000000b
Port 01
1000000000000001b
O
Port 02
1000000000000010b
Port 03
1000000000000011b
Port 04
1000000000000100b
Port 05
1000000000000101b
Port 06
1000000000000110b
Port 07
Port 08
1000000000000111b
1000000000001000b
Port 09
Port 10
1000000000001001b
1000000000001010b
Port 11
Port 12
1000000000001011b
1000000000001100b
Port 13
Port 14
1000000000001101b
1000000000001110b
Reserved
1000000000001111b
No-operation code
1xxxxxxxxxx1xxxxb
The no-operation code signals that the EAM device does not take part in forwarding decisions on this
packet. The TNETX15VE does not put out this code in normal operations. To successfully disable the
TNETX15VE, it is reset and not started. This causes the EAM interface to float, and external pullup
resistors are required on EAM15 and EAM04 (minimally) to supply the no-operation code to the
TNETX3150/TNETX3150A device. Erratic operation occurs if the TNETX3150/TNETX3150A address
matching is not enabled when the TNETX15VE is disabled. The TNETX15VE, when enabled, overrides
the operations of the TNETX3150/TNETX3150A matching circuitry; but, it is strongly advised to disable
the TNETX3150/TNETX3150A address matching if the TNETX15VE is active. This prevents two logic
blocks from attempting to control port suspension and other functions.
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