© VITESSE SEMICONDUCTOR CORPORATION

Page 13

12/1/99

741 Calle Plano, Camarillo, CA 93012 • 805/388-3700 • FAX: 805/987-5896

VITESSE

SEMICONDUCTOR CORPORATION

Advance Product Information

VSC8151

2.488Gb/s SONET/SDH

STS-48/STM-16 Section Terminator

G52225-0, Rev. 2.9

9.

DD

Disable descrambling

0

=

Normal Operation

1

=

Disable descrambling of incoming data

10. DS

Disable scrambling

0

=

Normal Operation

1

=

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 boundary. FWAx = “1” forces all A1 and A2 to be re-written (as

described in the A1/A2 boundary 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

0

0

CMU Ref Gen Outputs = Referenced from RXSCLKIN/32 (Transport Mode)

0

1

CMU Ref Gen Outputs = Referenced from external 77MHz PECL AIS Refclk (I_RCAIS)

1

0

CMU Ref Gen Outputs = Referenced from external 155MHz PECL AIS Refclk (I_RCAIS )

1

1

CMU Ref Gen Outputs = Based off external TTL AIS Refclk (I_RCVCO) 77MHz