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Functional Descriptions

VMDS-10488 VSC7511 Datasheet Revision 4.2

104

checks the flag AGED_FLAG for all entries in the MAC table. If an entry’s AGED_FLAG is already set

and the entry is of entry type 0, the entry is removed. If the AGED_FLAG is not set, it is set to 1. The flag

is cleared when receiving frames from the station identified by the MAC table entry. For more information,

see Hardware-Based Learning, page 103.

3.9.1.3

CPU Commands

The following table lists the set of commands that a CPU can use to access the MAC table. The MAC

table command is written to MACACCESS.MAC_TABLE_CMD. Some commands require the registers

MACLDATA, MACHDATA, and MACTINDX to be preloaded before the command is issued. Some

commands return information in MACACCESS, MACLDATA, and MACHDATA.

Table 75 •

MAC Table Commands

Command

Purpose

Use

LEARN

Insert/learn new entry

in MAC table.

Position given by

(MAC, VID)

Configure MAC and VID of the new entry in MACHDATA and

MACLDATA

. Configure remaining entry fields in MACACCESS.

The location in the MAC table is calculated based on (MAC,

VID).

FORGET

Delete/unlearn entry

given by (MAC, VID).

Configure MAC and VID in MACHDATA and MACLDATA.

AGE

Start age scan.

No preload required. Issue command.

READ

Read entry pointed to

by (row, column).

Configure row (0-1023) and column (0-3) of the entry to read

in:

MACTINDX.INDEX (row).

MACTINDX.BUCKET (column).

MACACCESS.VALID must be set to 0.

When MAC_TABLE_CMD changes to IDLE, MACHDATA,

MACLDATA, and MACACCESS contain the information read.

LOOKUP

Lookup entry pointed

to by (MAC, VID).

Configure MAC and VID of station to look up in MACHDATA

and MACLDATA. MACACCESS.VALID must be 1. Issue a

READ command. When MAC_TABLE_CMD changes to

IDLE, success of the lookup is indicated by

MACACESS.VALID. If successful, MACACCESS contains the

entry information.

WRITE

Write entry, MAC

table position given

by (row, column).

Configure MAC and VID of the new entry in MACHDATA and

MACLDATA. Configure remaining entry fields in

MACACCESS. The location in the MAC table is given by row

and column in MACTINDX.

INIT

Initialize the table.

No preload required. Issue command.

GET_NEXT

Get the smallest

entry in the MAC

table numerically

larger than the

specified (MAC, VID).

The VID and MAC

are evaluated as a

60-bit number with

the VID being most

significant.

Configure MAC and VID of the starting point for the search in

MACHDATA and MACLDATA.

When MAC_TABLE_CMD changes to IDLE, success of the

search is indicated by MACACESS.VALID. If successful,

MACHDATA, MACLDATA, and MACACCESS contain the

information read.

IDLE

Indicate that MAC

table is ready for new

command.

No preload required.

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