VSC8140QR VITESSE [Vitesse Semiconductor Corporation], VSC8140QR Datasheet - Page 7

• Manufacturer Part Number: VSC8140QR
• Description: 2.48832Gb/s 16:1 SONET/SDH Transceiver with Integrated Clock Generator
• Manufacturer: VITESSE [Vitesse Semiconductor Corporation]

VSC8140
Data Sheet
9/6/00
G52251-0, Rev. 4.0
Facility Loopback
high, the Facility Loopback mode is activated and the high-speed serial receive data (RXIN) is presented at the
high-speed transmit output (TXOUT), as depicted in Figure 10. In addition, the high-speed receive clock input
(RXCLKI) is selected and presented at the high-speed transmit clock output (TXCLKOUT). In Facility Loop-
back mode, the high-speed receive data (RXIN) is also converted to parallel data and presented at the low-speed
receive output pins (RXOUT[15:0]). The receive clock (RXCLKIN) is also divided down and presented at the
low-speed clock output (RXCLK16O).
Equipment Loopback Data Path
Equipment Loopback mode is activated, the high-speed transmit data generated from the parallel to serial con-
version of the low-speed data (TXIN[15:0]) is selected and converted back to parallel data in the receiver sec-
tion and presented at the low-speed parallel data outputs (RXOUT[15:0]), as shown in Figure 11. The internally
generated OC-48 clock is used to generate the low-speed receive output clocks (RXCLK16O and
RXCLK16_32O). In Equipment Loopback mode, the transmit data (TXIN[15:0]) is serialized and presented at
the high-speed output (TXOUT) along with the high-speed transmit clock (TXCLKOUT) which is generated by
the on-chip PLL.
The facility loopback function is controlled by the FACLOOP signal. When the FACLOOP signal is set
The Equipment Loopback function is controlled by the EQULOOP signal, which is active high. When the
TXCLKOUT+
TXCLKOUT-
RXCLKIN+
RXCLKIN-
FACLOOP
TXOUT+
TXOUT-
RXIN+
RXIN-
741 Calle Plano, Camarillo, CA 93012 • 805/388-3700 • FAX: [phone]
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VITESSE
Figure 10: Facility Loopback Data Path
VITESSE SEMICONDUCTOR CORPORATION
SEMICONDUCTOR CORPORATION
D Q
0
0
1
1
Transceiver with Integrated Clock Generator
16:1 Parallel to
Serial
1:16 Serial to
Parallel
2.48832GHz
PLL
2.48832Gb/s 16:1 SONET/SDH
RXOUT[15:0]
RXCLK32O
RXCLK16O
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