KSZ9563RNXI datasheet(182/226 Pages) MICROCHIP

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KSZ9563R

DS00002419D-page 182

 2017-2018 Microchip Technology Inc.

5.3.1.1

Address Lookup Table Read Operation

Write the index to the ALU Table Index 0 Register and ALU Table Index 1 Register.

a) A MAC address is used for the hashing indexing function, which is the normal access mechanism for this

table.

b) A FID is also required if VLAN is enabled.

c) If directly addressing the table, a 12-bit index is written to bits [11:0] of the MAC address field.

Write to the ALU Table Access Control Register.

a) Set the ACTION field to 10 to indicate a read operation.

b) Select the addressing method via the DIRECT bit.

c) Set the START_FINISH bit to initiate the operation.

Read / poll the ALU Table Access Control Register.

a) The START_FINISH bit transitions to 0 to indicate that the operation is complete.

b) Once START_FINISH is 0, the VALID bit indicates whether or not a valid entry was found. If VALID is false,

there is no need to proceed to step 4.

c) The VALID_ENTRY_OR_SEARCH_END bit is an aggregate of the START_FINISH bit and the VALID bit. It

is intended for use when accessing registers by in-band management (IBA), where polling multiple bits is

less practical.

Read the contents of the returned table entry from the ALU Table Entry 1 Register, ALU Table Entry 2 Register,

ALU Table Entry 3 Register, and ALU Table Entry 4 Register. If no VALID entry is returned, these registers will

contain all zeros.

FIGURE 5-3:

ADDRESS LOOKUP TABLE CONFIGURATION

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