vsc880 Vitesse Semiconductor Corp, vsc880 Datasheet - Page 7

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

G52191-0, Rev 4.2
01/05/01
Data Sheet
VSC880
1.2.3 IDLE Words
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. These connection bits will be in the same location as in the CRQ word. In cell
mode, IDLEs will be transmitted from the switch chip if the force IDLE (FI) bit is set in the control registers. IDLE
words are also used to detect link error conditions. If the switch chip detects an IDLE word, it uses a bit mask to ver-
ify the proper bit pattern within the word.
1.3 Loopback
BSTLPBK signal is set HIGH and TESTEN is set LOW, the serial transmit data is looped back to the serial receive
side for all 16 channels. If the BSTLPBK signal is set HIGH and TESTEN is set HIGH, the serial transmit data is
looped back to the serial receive side for channels 0-7 only. If the FACLPBK signal is set HIGH, the serial receive
signal is looped back to the serial output for all 16 channels. Each channel can also be programmed to be looped back
separately from serial input to serial output by using the control registers described below. The VSC880 does not
support simultaneous BIST and facilty loopback functions (either FACLPBK pin or LPBK[15:0] register).
1.4 Internal Register Definitions
along with CSEL and CWEN to read or write data through the CDATA[7:0] interface. CWEN is set LOW to write
and HIGH to read from this port. If CSEL is HIGH, the outputs become high impedance and the inputs become
Where:
B[1:0]00=Undefined (during normal operation) or alignment word
C[4:0]Command type
D[15:0]Optional data payload
IDLE words are the default word used on the serial channel when none of the other word types are present. In
The VSC880 supports a loopback function at the serial interfaces which is used in built-in self-test mode. If the
The internal status and control registers are defined in the following table. The address signal ADDR[5:0] is used
33 32
0 0
01=Flow control channel,
10=Flow control channel,
11=Acknowledge (from switch chip only) or link initialization reset or cell clock in cell mode
31 30 29
1 B B
1 0
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 (TBD)
Default=1010101010101010
IDLE Word from switch=Current switch outputs this port is connected to
If C[4:0]=01000, D[3:0]=DLYEN/CCKIN value
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012
28 27 26 25 24
C C C C C
04 03 02 01 00
-- Command --
D[15] is for port 0, D[0] is for port 15
Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]
VITESSE
SEMICONDUCTOR CORPORATION
23 22 21 20
D D D D
15 14 13 12
Internet: www.vitesse.com
19 18 17 16
D D D D
11 10 09 08
-- Data --
15 14 13 12
D D D D
07 06 05 04
11 10 09 08
D D D D
03 02 01 00
High Performance 16x16
Serial Crosspoint Switch
07 06 05 04
1 0 1 0
03 02 01 00
1 0 1 0
Page 7