CS8900-CQ View Datasheet(PDF) - Cirrus Logic

Part Name

Description

MFG CO.

CS8900-CQ

Highly-Integrated ISA Ethernet Controller

Cirrus Logic 

CS8900

Destination Address (DA)

from incoming frame

CS8900

CRC

Logic

(MSB) 32-bit CRC value (LSB)

6-bit Hash Register (HR)

[Hash Table Index]

to

Hashed

1

bit

64-input

OR gate

6-to-64 decoder

64

64-bit Logical Address Filter (LAF)

Written into PacketPage base + 150h

Figure 5.5. Hash Filter Operation

Address

Type of

Received

Frame

Individual

Address

Multicast

Address

Broadcast

Address

Erred

Frame?

Passes

Hash

Filter?

no

yes

no

no

yes

don’t care

no

yes

no

no

yes

don’t care

no yes (Note 1)

no yes (Note 2)

no

no

yes

don’t care

Bits F-A

Contents of RxEvent

Bit 9

Hashed

Hash Table Index

1

Extra Runt CRC Broadcast Individual

0

Data

Error

Adr

Extra Runt CRC Broadcast Individual

0

Data

Error

Adr

Hash table index

1

Extra Runt CRC Broadcast Individual

0

Data

Error

Adr

Extra Runt CRC Broadcast Individual

0

Data

Error

Adr

Extra Runt CRC Broadcast Individual

1

Data

Error

Adr

(actual value X00010)

Extra Runt CRC Broadcast Individual

0

Data

Error

Adr

Extra Runt CRC Broadcast Individual

0

Data

Error

Adr

Extra Runt CRC Broadcast Individual

0

Data

Error

Adr

Bit 8

RxOK

1

1

0

1

1

0

1

1

1

0

Bit 6

IAHash

1

0

0

0

0

0

0

0

0

0

Notes:

1. Broadcast frames are accepted as Multicast frames if and only if all the following conditions are

met simultaneously:

a) the Logical Address Filter is programmed as: (MSB) 0000 8000 0000 0000h (LSB). Note that

this LAF value corresponds to a Multicast Addresses of both all 1s and 03-00-00-00-00-01.

b) The Rx Control Register (register 5) is programmed to accept IndividualA, MulticastA, RxOK-only,

and the following address filters were enabled: IAHashA and BroadcastA.

2. NOT (Note 1).

Table 5.7. Contents of RxEvent Upon Various Conditions

88

DS150PP2

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