VSC870 查看數據表（PDF） - Vitesse Semiconductor

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VSC870

High Performance Serial Backplane Transceiver

Vitesse Semiconductor 

VITESSE

SEMICONDUCTOR CORPORATION

High Performance Serial

Backplane Transceiver

Data Sheet

VSC870

11XX0=Command word for receiving port card

D[15:0]Optional data payload:

Default=1010101010101010

IDLE Word from switch=Output(s) this port is connected to;

D[15] is equal to port 0, and D[0] is equal to port 15.

If C[4:0]=01000, D[3:0]=DLYEN/CCKIN value

1.2.4 Command Word Format on the Serial Data Lines

The command word format as seen at the serial output of the transceiver or switch chip is shown below. Two

overhead bits are added by the transceiver or switch to designate a command word (00) to the receiving switch chip or

transceiver. The serial data is transmitted with the MSB first. In Packet Mode, the IDLE word from the switch always

returns the current output connections for the port.

33 32

00

31 30 29

1BB

10

28 27 26 25 24

CCCCC

04 03 02 01 00

-- Command --

23 22 21 20

DDDD

15 14 13 12

19 18 17 16 15 14 13 12

DDDD

11 10 09 08

DDDD

07 06 05 04

-- Data --

11 10 09 08

DDDD

03 02 01 00

07 06 05 04

1010

03 02 01 00

1010

Where:

B[1:0]00=Undefined (during normal operation) or alignment word

01=Flow control channel,

10=Flow control channel,

11=Acknowledge (from switch chip only) or link initialization reset or cell clock in cell mode

C[4:0]Command type:

00XXX=Link Control (00000=ALIGN word, 00111=IDLE word)

01XX0=Command word for transceiver (01000=set DLYEN/CCKIN value)

10XX0=Command word for switch

11XX0=Command word for receiving port card)

D[15:0]Optional data payload:

Default=1010101010101010

IDLE Word from switch=Output(s) this port is connected to;

D[15] is equal to port 0, and D[0] is equal to port 15.

If C[4:0]=01000, D[3:0]=DLYEN/CCKIN value

1.2.5 IDLE Words

IDLE words are the default word used on the serial channel when none of the other word types are present. In

most cases, these words are automatically generated by the transceiver or switch chip. In Packet Mode, IDLE words

are inserted between packets and the IDLE word from the switch always returns the current output connections for

the port that is receiving the IDLEs. If the user does not have data to send, IDLE words can be loaded into the parallel

interface, or the TXEN signal can be set LOW which forces the transceiver to send IDLEs to the switch chip. In cell

mode, IDLEs will be transmitted from the switch chip if the Force IDLE bit is set in the switch chip (see the VSC880

data sheet). See sections 2.0 and 3.0 for more details. IDLE words are also used to detect link error conditions. If the

transceiver detects and IDLE word, it uses a bit mask to verify the proper bit pattern within the word.

Page 10

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com

Internet: www.vitesse.com

G52190-0, Rev 4.1

01/05/01

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