MT8926 Zarlink Semiconductor, MT8926 Datasheet - Page 22

• Manufacturer Part Number: MT8926
• Description: T1 Performance Monitoring Adjunct Circuit (PMAC)
• Manufacturer: Zarlink Semiconductor

SEMICMF.019
Data Sheet
2.0
Figure 9 on page 21 illustrates a typical application of a MT8926 PMAC. T1 data is transmitted and received using
a generic Line Interface Unit (LIU). The LIU passes the received data and extracted clock to both the MT8926 and
MT8976. E8Ko (MT8976) is derived from E1.5i by dividing it by 193 and aligning the result with the receive framing.
E8Ko (MT8976) connects to E8Ki (MT8926), and is used by the MT8926 for frame alignment. E8Ko (MT8926) is
connected to C8Kb of the MT8941. In MT8941 normal mode, C8Kb is the reference clock for the ST-BUS and
transmit signals (F0, C4 and C2). This 8 kHz output can be turned off (output high) at the MT8926 so the MT8941
reference clock can be derived from another interface. The intrinsic jitter (typical 0.07 UI) and jitter attenuation of
the MT8941 will meet T1.408 requirements (see MT8941 data sheet).
Control of the MT8926 is accomplished over the CSTi1 ST-BUS stream, which is shared by the MT8926 and
MT8976. Status data (Performance Monitoring Information) is inserted into the MT8976 CSTo stream by the
MT8926 and is output on its CSTo stream. This CSTo stream data is routed through the MT8980 switch, in
message mode, to the microprocessor. The microprocessor will assemble the information section of the
T1.403/T1.408 message-oriented signal and pass it to the MT8952 HDLC controller for transmission over the
facility data link. The MT8952 must be in external timing mode and will be clocked by the RxFDLCLK output to the
MT8976. The assembly and transmission of the message-oriented signal is under control of the 1SEC output of the
MT8926.
Bit-oriented messages are also transmitted and received via MT8980 message mode access to the CSTi1 and
CSTo streams. The MT8926 will receive bit-oriented messages from the receive T1 line (i.e., RxA and RxB). Both
bit-oriented and message-oriented signals are transmitted over the MT8926 FDLo to MT8976 TxFDL link.
Payload loopback is performed by internally connecting DSTi1 to DSTo of the MT8926 (under control of the CSTi1
stream), instead of the normal connection of DSTi0 to DSTo (see Figure 6 on page 8).
To/From
other
interfaces
Message-Oriented
Performance
Monitoring
T1.403/T1.408
Message/
Signal Control
Storage
Data
interfaces
Applications
From
other
STi2
STo3
STo7
STi7
MT8980
MT8952
P
CDSTo
CDSTi
STo0
STo1
STo2
INT0
INT1
STi0
STi1
CKi
C4i
F0i
Figure 9 - Typical T1.403/T1.408 Application
4.7k
VDD
16.384
MHz
Osc.
E8Ko
CSTo
DSTi0
DSTi1
IRQ
1SEC
FDLi
MT8926
CSTi1
CSTi0
ECLK
DSTo
FDLo
E8Ki
RxA
RxB
C2i
F0i
C8Kb
C4b C2o F0b F0i CVb
MT8941
To other
Interfaces
RxA
RxB
E1 5i
F0i
C2i
CSTi1
E8Ko
CSTo
TxFDL
DSTi
DSTo
CSTi0
RxFDL
RxFDLCLK
TxFDLCLK
MT8976
RxSF
C1.5i
TxSF
12.352
XCtl
TxA
TxB
MHz
Osc.
To other T1
Interfaces
Interface
(LIU)
Line
Unit
MT8926
Receive
Transmit
T1
T1
21