MT8910-1
Preliminary Information
the superframe position. This function can also be
activated in software (LT mode only) through a bit in
Control Register 1 (TxSFB). The transition of this bit
from a 1 to a 0 will reset the superframe counter, and
the beginning of the transmitted superframe will be
referenced to the ST-BUS frame after the frame in
which the transition in the TxSFB bit occurred.
superframe synchronization has been achieved. In
the NT mode, the TxSFB bit is ignored since the
transmit superframe has a fixed phase relationship
with respect to the received superframe.
The MT8910-1 has two possible system port
configurations; single port mode or dual port mode.
In the single port mode, the MT8910-1 uses the first
four timeslots of the DSTi and DSTo data streams
(as shown in Figure 8). ST-BUS Channel 0 is
allocated to the D-channel, ST-BUS Channel 1 to the
C-channel, while ST-BUS Channel 2 and 3 are
In the NT mode, the SFb pin is an output which
generates an active low signal at the boundary of the
transmit superframe. Since the SFb is referenced to
the receive time base, SFb is only valid after
F0b
C4b
DSTo
D0 D1
D0 D1
C7 C6
C7 C6
C1 C0 B7 B6
B1 B0 B7 B6
B1 B0
B1 B0
D0
D0
DSTi
F0od
C1 C0 B7 B6
B1 B0 B7 B6
15.6 µsec
Channel Time 0
D-Channel
Channel Time 1
C-Channel
Channel Time 2
B1-Channel
Channel Time 3
B2-Channel
Reserved
Figure 8 - ST-BUS Channel Assignments in Single Port Mode
F0b
C4b
B7 B6 B5 B4 B3 B2 B1 B0
B7 B6 B5 B4 B3 B2 B1 B0
B7
DSTi
C7 C6 C5 C4 C3 C2 C1 C0
D0 D1
C7
B7
C7
CDSTi
B7 B6 B5 B4 B3 B2 B1 B0
B7 B6 B5 B4 B3 B2 B1 B0
DSTo
CDSTo
F0od
C7 C6 C5 C4 C3 C2 C1 C0
D0 D1
3.9 µsec
62.5 µsec
125 µsec
Channel Time 16
Channel Time 0
Reserved
Figure 9 - ST-BUS Channel Assignment in Dual Port Mode
9-12
MITEL [ MITEL NETWORKS CORPORATION ]
