vsc880 Vitesse Semiconductor Corp, vsc880 Datasheet - Page 14

• Manufacturer Part Number: vsc880
• Description: High Performance 16x16 Serial Crosspoint Switch Semiconductor Corporation
• Manufacturer: Vitesse Semiconductor Corp

High Performance 16x16
Serial Crosspoint Switch
Page 14
2.2.2 CRQ Word Format on the Serial Data Lines to the Switch
added by the transceiver to designate a CRQ word to the receiving switch chip. The signal ARB, AOA and BRK are
used to control modes of operation in the switch chip. The serial data is transmitted with the MSB first.
2.2.3 CRQ Word Format on the Serial Data Line From the Switch
added by the switch chip to designate a command word (00) to the transceiver. This word is sent on to the receiving
port card when an ACK is sent to the transmitting port card. The command word contains the current active
connections for this input in the switch chip. The serial data is transmitted with the MSB first.
Where:
A[1:0]11=to switch chip, 00=from switch chip
B[1:0]00=Undefined,
D[19:0]20 bit data payload
The CRQ command word format as seen at the output of the transceiver is shown below. Two overhead bits are
33 32
0 0
Where:
B[1:0]00=Undefined,
ARB1=Multi Queue arbitration
AOA1=Acknowledge on all connections granted, 0=Acknowledge on any connections granted
BRK 1=Break previous connection, 0=Do not break previous connection
C[0:15] Connection request bit map. Set bit high for each output requested
D[3:0] User defined data sent by transmitting port card
The CRQ command word format as seen at the output of the switch chip is shown below. Two overhead bits are
33 32
A A
1 0
01=Flow control channel,
10=Flow control channel,
11=Acknowledge to transceiver
01=Flow control channel,
10=Flow control channel,
11=Undefined
31 30 29 28 27
0 B B 1 0
31 30 29 28
0 B B 1
1 0
1 0
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012
27 26 25 24
0 1 1 0
26 25 24
A A B
R O R
B A K
Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]
VITESSE
SEMICONDUCTOR CORPORATION
23 22 21 20
D D D D
19 18 17 16
23 22 21 20
C C C C
00 01 02 03
Internet: www.vitesse.com
19 18 17 16
D D D D
15 14 13 12
19 18 17 16
C C C C
04 05 06 07
------ Connection Bits ------
--------------- Data Payload ----------------
15 14 13 12
D D D D
11 10 09 08
15 14 13 12
C C C C
08 09 10 11
11 10 09 08
D D D D
07 06 05 04
11 10 09 08
C C C C
12 13 14 15
07 06 05 04
D D D D
03 02 01 00
07 06 05 04
D D D D
03 02 01 00
--Data--
03 02 01 00
1 0 1 0
03 02 01 00
1 0 1 0
Data Sheet
VSC880
G52191-0, Rev 4.2
01/05/01