TNETX15VE datasheet(88/113 Pages) TI1

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TNETX15VE

VLAN-ENGINE ADDRESS-LOOKUP DEVICE

SPWS028B – APRIL 1997 – REVISED SEPTEMBER 1997

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

PRINCIPLES OF OPERATION

DEL logic operation (management address deletions)

DIO ADDRESS

0x2C

BYTE 3

BYTE 2

BYTE 1

BYTE 0

0x48

0x4C

Delnode7–Delnode0

Adddelcontrol

Delnode23–Delnode16

Delnode31–Delnode24

Delnode39–Delnode32

Delnode47–Delnode40

DelVLANID

Delnode15–Delnode8

Delport

The DEL logic operation is controlled through the delnode, delVLANID, and delport registers and the

adddelcontrol register. Management delete commands are given through the DEL, DELP, and DELV bits in the

adddelcontrol register.

The steps for deleting any specific address are as follows (multicast and secured unicast can only be deleted

this way):

• Writing the node address in the delnode register and the node’s VLAN in delVLANID

• Asserting the DEL bit in adddelcontrol

The TNETX15VE also can delete all addresses on a port. The steps for deleting all addresses on a port are:

• Writing the port in delport. Delnode and delVLANID are don’t cares and are ignored.

• Asserting the DELP bit in adddelcontrol

As in FIND, only unicast addresses are associated with a port; only unicast unsecured addresses are deleted

with a DELP command. Another multiple-delete command is used when a deletion by VLAN is desired. The

TNETX15VE has the capability to delete all unsecured, unicast addresses on a particular VLAN. The steps for

this command are:

• Writing the VLAN to be deleted in delVLANID. Delnode and delport are don’t cares and are ignored.

• Asserting the DELV bit in adddelcontrol

The DEL logic operation locks the delnode and delVLANID registers on all delete commands to ensure that they

do not change during the deletions. Reads to these registers are still possible. The DEL, DELP, AND DELV bits

in adddelcontrol remain in the 1 state until the deletion is complete. If DELP and DELV are both set, both the

delport and delVLANID fields are active. Unsecured unicast addresses meeting both conditions are deleted.

Much like the management adds, having a sticky bit for DEL gives the programmer the opportunity to set up

or perform other register operations without having to wait for the delete completion. A polling method is used

to find out if the delete is finished. This involves reading adddelcontrol to determine if the command bit used

has returned to 0.

interrupts

The TNETX15VE implements interrupts to ease the management processor’s tasks. The interrupts are used

to indicate changes to the lookup table. It indicates that a new address is added, an address changed ports,

an address changed ports and is secure, and an address is deleted due to the aging process. It also indicates

that a FIND operation is completed, the RX NBLCK has data (not empty), the statistic registers are half full (and

the possibility for an overflow is present) and the lookup table is full. The TNETX15VE indicates that interrupts

to the CPU exist by setting to 1 its level-sensitive EINT terminal. The EINT terminal is asserted when any of the

possible interrupt conditions are met.

The interrupt register is readable at all times and contains all the current TNETX15VE interrupts. The interrupt

whether or not it is currently masked.

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