Digi NS9215 manual G i s t e r H a s h T a b l e s, Pro, Prm, Pra, Broad

Models: NS9215

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E T H E R N E T C O M M U N I C A T I O N M O D U L E

RegisterHash Tables

Register

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Reserved

 

 

 

 

 

PRO

PRM

PRA

BROAD

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Register bit

assignment

Bits

Access

Mnemonic

Reset

Description

 

 

 

 

 

 

 

D31:04

N/A

Reserved

N/A

N/A

 

 

 

 

 

 

 

D03

R/W

PRO

0

Enable promiscuous mode; receive all frames

 

 

 

 

 

 

 

D02

R/W

PRM

0

Accept all multicast frames

 

 

 

 

 

 

 

D01

R/W

PRA

0

Accept multicast frames using the hash table

 

 

 

 

 

 

 

D00

R/W

BROAD

0

Accept all broadcast frames

 

 

 

 

 

 

R e g i s t e r H a s h T a b l e s

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The MAC receiver provides the station address logic with a 6-bit CRC value that is the upper six bits of a 32-bit CRC calculation performed on the 48-bit multicast destination address. This 6-bit value addresses the 64-bit multicast hash table created in HT1 (hash table 1) and HT2 (hash table 2). If the current receive frame is a multicast frame and the 6-bit CRC addresses a bit in the hash table that is set to 1, the receive frame will be accepted; otherwise, the receive frame is rejected.

HT1 stores enables for the lower 32 CRC addresses; HT2 stores enables for the upper 32 CRC addresses.

HT1

Address: A060 0504

 

 

 

 

 

 

 

 

 

 

 

 

 

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HT1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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HT1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Register bit assignment

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bits

 

Access

 

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Reset

 

 

 

 

 

Description

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D31:00

 

R/W

 

HT1

 

0x00000000

 

 

 

 

CRC 31:00

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

302Hardware Reference NS9215

Page 302
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Digi NS9215 manual G i s t e r H a s h T a b l e s, Pro, Prm, Pra, Broad