MT9044AL1 Zarlink Semiconductor, Inc., MT9044AL1 Datasheet - Page 19

• Manufacturer Part Number: MT9044AL1
• Description: Dual Reference Frequency Selectable Digital PLL with Multiple Clock Outputs for T1/E1 (ITU-T G.812 type IV), Stratum (3, 4, 4E) and STS-3/OC3 Systems
• Manufacturer: Zarlink Semiconductor, Inc.

Dual E1 Reference Sources with MT9044 in
Manual Control
For systems requiring complex state machine
control, the application circuit shown in Figure 16
using Manual Control may be used.
In this circuit, the MT9044 is operating Manually and
is using a controller for all mode changes. The
controller sets the MT9044 modes (Normal, Holdover
or Freerun) by controlling the MT9044 mode/control
select pins (MS2 and MS1). The input (Primary or
Secondary) is selected with the reference select pin
(RSEL). TIE correction from Primary Holdover Mode
to Primary Normal Mode is enabled and disabled
with the guard time input pin (GTi). The input to
output phase alignment is re-aligned with the TIE
External Stimulus
RX Line
RX Line
To Line 1
TX Line
TX Line
To Line 2
XFMR
XFMR
XFMR
XFMR
To
To
To
To
Figure 16 - Dual E1 Reference Sources with MT9044 in 8kHz Manual Control
TTIP
TRING
RTIP
RRING
TTIP
TRING
RTIP
RRING
MT9075
MT9075
MT8985
RxFP
RxFP
DSTo
DSTo
DSTi
DSTi
STo0
STo1
LOS
LOS
STi0
STi1
C4i
C4i
C4i
F0i
F0i
F0i
circuit reset pin (TCLR), and a complete device reset
is done with the RST pin.
The controller uses two stimulus inputs (LOS)
directly from the MT9075 E1 interfaces, as well as an
external stimulus input. The external input may come
from a device that monitors the status registers of
the E1 interfaces, and outputs a logic one in the
event of an unacceptable status condition.
For complete Manual Control state machine details,
refer to Table 4 for the State Table, and Figure 7 for
the State Diagram.
CONTROLLER
SEC
TRST
RST
PRI
LOS1
LOS2
MS1
MS2
RSEL
MT9044
C1.5o
OSCi
C4o
FS1
FS2
F0o
GTi
+ 5V
Out
20MHz
MT9044
CLOCK
±
32ppm
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