PM5366-PI PMC-Sierra, Inc., PM5366-PI Datasheet - Page 233

• Manufacturer Part Number: PM5366-PI
• Description: HIGH DENSITY 84/63 CHANNEL VT/TU MAPPER AND M13 MULTIPLEXER
• Manufacturer: PMC-Sierra, Inc.

PRELIMINARY
DATASHEET
PMC-2010672
13.7.1 Notes on 77.76 MHz SBI Bus Operation
PROPRIETARY AND CONFIDENTIAL
Figure 61 illustrates the operation of the SBI ADD Bus, using positive and
negative justification requests as an example. (The responses to the justification
requests would take effect during the next multi-frame.) The negative
justification request occurs on the DS-3#3 tributary when SAJUST_REQ is
asserted high during the H3 octet. The positive justification occurs on the DS-3#2
tributary when SAJUST_REQ is asserted high during the first DS-3#2 octet after
the H3 octet.
SBI bus operation at 77.76MHz is simply a byte interleaved multiplex of a 19.44
MByte/s stream with idle cycles. The STM-1 of interest is identified by the
LSTM[1:0] bits of the Master Bus Configuration register. On the Add bus, the
three unused STM-1s are simply ignored, including parity. On the Drop bus, the
unused STM-1s are high-impedance. The following is of special note:
1. Regardless of the state of the SSTM[1:0] bits, the SAC1FP and SDC1FP
2. Up to four devices may be directly connected to the same bus. Current
3. The Telecom bus becomes unconditionally high-impedance upon either a
pulses always identify the first byte of the frame.
consumption is minimized if all devices are the same (ie. all TEMAP-84s).
All devices must receive the same SAC1FP and SDC1FP signals.
hardware or software reset. All necessary configuration and at least one
SDC1FP pulse should precede the setting of the GSOE register bit.
ISSUE 1
221
HIGH DENSITY 84/63 CHANNEL VT/TU MAPPER
AND M13 MULTIPLEXER
PM5366 TEMAP-84