PM4354 Datasheet, PDF (401/463 Pages) PMC-Sierra, Inc – Four Channel Combined E1/T1/J1 Transceiver/Framer

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PM4354 COMET-QUAD
DATASHEET
PMC-1990315
ISSUE 6
FOUR CHANNEL COMBINED E1/T1/J1
TRANSCEIVER / FRAMER
• RSYNC_SEL[1:0] is the value of the RSYNC_SEL[1:0] bits of the RSYNC Select register.
In T1 mode, the 1x clock illustrated will be nominally 1.544 MHz even if the CSU Configuration
register has been programmed for XCLK to accept a 2.048 MHz clock.
Figure 36
- RSYNC Generation
XCLK
Analog Clock
Synthesis
1x
clk
Unit (CSU)
1x clk
1x clk
1x clk
COMET-QUAD
Quadrant 4
Quadrant 3
Quadrant 2
Quadrant 1
E1/T1B ^{Divider to 8kHz}
Recovered Clock
ALOSV ₁
LOSV
0
1
RJAT
0
RSYNC_MEM
RSYNC_ALOSB
8 kHz clk ₁
0
RSYNCSEL
11
10
RSYNC
01
0
00
1
RSYNC_SEL[1:0]
The above diagram illustrates that RSYNC generation is configurable. RSYNC_ALOSB selects
which criterion (either Analog Loss of Signal or Loss of Signal) causes RSYNC generation to
switch over from the Recovered Clock to XCLK. If RSYNC_MEM is logic 1, then RSYNC will be
held high during the loss of signal condition. RSYNCSEL selects between the line rate clock or
8kHz version of the clock. RSYNC_SEL[1:0] selects which quadrant’s internal RSYNC signal is
presented on the RSYNC pin.
Note: RSYNC is always jitter attenuated by the RJAT. Refer to the RJATBYP register bit
description and the recommendations in the RJAT Divider N2 Control register description for
additional information.
12.13 Backplane Configuration
The following tables provide programming guidelines for the Backplane Interfaces. The tables
correspond to the commonly used modes discussed in Functional Description section of this
document. In many cases, variations in the register settings are possible. Because of interaction
between register settings, it is highly recommended that the below tables be used in conjunction
with the register descriptions found in the Normal Mode Register section. Although the tables
below are intended to provide guidelines, an exhaustive list of register settings for all eventualities
may not be given.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC. AND FOR ITS CUSTOMERS’ INTERNAL USE
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