MT8941
CMOS
MT8980/81
MT8941
MS0
MS1
MS2
MS3
F0i
C12i
EN
CV
C8Kb
C16i
EN
C4o
EN
C2o
V
DD
MH89790B
C4b
C2i
C2o
F0i
E8Ko
F0b
DSTi
DSTo
CSTi0
CSTi1
CSTo
OUTA
OUTB
Y
o
V
SS
RST
RxT
RxR
Mode of Operation for the MT8941
C
R
V
DD
DPLL #1 - NOT USED
DPLL #2 - NORMAL (MS0=1; MS1=0; MS2=1; MS3=1)
RECEIVE
TRANSMIT
CEPT
PRIMARY
MULTIPLEX
DIGITAL
LINK
ST-BUS
SWITCH
Crystal Clock
(16.384 MHz)
Figure 12 - Synchronization at the Slave End of the CEPT Digital Transmission Link
Figures 11 and 12 show how the MT8941 can be
used to synchronize the ST-BUS to the CEPT
transmission link at the master and slave ends.
Generation of ST-BUS Timing Signals
The MT8941 can source the properly formatted ST-
BUS timing and control signals with no external
inputs except the crystal clock. This can be used as
the standard timing source for ST-BUS systems or
any other system with similar clock requirements.
Figure 13 shows two such applications using DPLL
#2. In one case, the MT8941 is in FREE-RUN
mode with an oscillator input of 16.384 MHz. In the
other case, it is in NORMAL mode with the C8Kb
input tied to V
DD
. For these applications, DPLL #2
does not make any corrections and therefore, the
output signals are free from jitter. DPLL #1 is
completely free.
For prototyping purposes, Mitel offers the MT8941
Crystal Kit (MB6022) which contains 16.384 MHz
and 12.352 MHz clock oscillators.
MT8941
MS0
MS1
MS2
MS3
F0i
C12i
EN
CV
C8Kb
C16i
EN
C4o
EN
C2o
Ai
Bi
V
SS
RST
V
DD
DPLL #1 - NOT USED
DPLL #2 - FREE-RUN MODE
(MS0=0; MS1=0;MS2=1;
MS3=1)
MS0
MS1
MS2
MS3
F0i
C12i
MT8941
V
DD
C4o
C4b
ST-BUS
C4o
C4b
ST-BUS
Crystal Clock
(16.384 MHz)
C2o
C2o
F0b
TIMING
SIGNALS
Crystal Clock
(16.384 MHz)
EN
CV
C8Kb
C16i
EN
C4o
EN
C2o
Ai
Bi
V
SS
RST
C2o
C2o
F0b
TIMING
SIGNALS
DPLL #1 - NOT USED
DPLL #2 - NORMAL MODE
(MS0=0; MS1=0;
MS2=1; MS3=1)
R
V
DD
C
C
R
V
DD
Figure 13 - Generation of the ST-BUS Timing Signals
3-54
MITEL [ MITEL NETWORKS CORPORATION ]
