VITESSE
SEMICONDUCTOR CORPORATION
Advance Product Information
2.488Gb/s SONET/SDH
STS-48/STM-16 Section Terminator
VSC8151
9. DD
1
Disable descrambling
0
=
=Normal Operation
Disable descrambling of incoming data
10. DS
1
Disable scrambling
0
=
=Normal Operation
Disable scrambling of outgoing data
11. NS
Non-SONET: Allows device to pass non-SONET data such as Gigabit Ethernet. NOTE: If
non-SONET data is being transmitted, Frame Detect must be disabled. (When NS=”1”, set
FRD1=”1” and FRD0=”0”).
0
=SONET data transmitted
1
=
non-SONET data transmitted
12. FWAx
Forced write of A1/A2 boundry. FWAx = “1” forces all A1 and A2 to be re-written (as
described in the A1/A2 boundry refresh section)
0
=Normal Operation
1
=
Forced re-write of A1/A2
13. MXC[1:0] VSC8151 CMU reference generator output clock selection (see Figure 3)
MXC1
MXC0
CKREFP/N, CKREFT Reference Generator Outputs
CMU Ref Gen Outputs = Referenced from
RXSCLKIN/32 (Transport Mode)
0
0
CMU Ref Gen Outputs = Referenced from external 155MHz PECL AIS
Refclk (I_RCAIS )
0
1
CMU Ref Gen Outputs = Referenced from external 77MHz PECL AIS
Refclk (I_RCAIS)
1
1
0
1
CMU Ref Gen Outputs = Based off external TTL AIS Refclk (I_RCVCO)
G52225-0, Rev. 2.3
8/16/99
VITESSE SEMICONDUCTOR CORPORATION
741 Calle Plano, Camarillo, CA 93012 • 805/388-3700 • FAX: 805/987-5896
Page 13
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