MT90812 Mitel Networks Corporation, MT90812 Datasheet - Page 12

• Manufacturer Part Number: MT90812
• Description: Integrated Digital Switch (IDX)
• Manufacturer: Mitel Networks Corporation

MT90812
multiplexed bus specifications. The MT90812 can operate in either
register as specified in section “Control Register (CTL)” on page 54.
2.0
There are two local serial Time Division Multiplexed (TDM) streams. These streams at STi/o0 and STi/o1
provide a link between the MT90812 and other peripheral devices, including those in the ST-BUS family (e.g.
MT9160B, MT9171/72, MT8930, MT8910). The two serial streams operate at 2.048 Mbit/s and are arranged in
125us wide frames, each comprising 32 8-bit channels. Refer to Section 9.2, “Serial Data Interface Timing”.
The MT90812 can support Primary Rate or Basic Rate devices. Using the Basic Rate devices (e.g. MT9171/72
DNIC) in dual port mode the D-Channel should be assigned to STi/o1 streams. D-channel signalling support is
provided for any timeslot on the STi/o1 streams for the HDLC Controller mode. The DBRT can access any
timeslot and stream. Refer to “D-Channel Signalling Support” on page 30 and “Local TDM Channel
Assignment” on page 76.
3.0
The expansion bus operates in 2 modes, IDX Link and TDM Link modes. The modes will be described in the
following sections. Section 24.1 describes the timing references used for both Expansion bus modes.
3.1
In this mode, the expansion bus at EST0 and EST1, are regular output and input serial streams, respectively.
They operate at either 2.048, 4.096 or 8.192 Mbit/s. Refer to Fig. 4.
At 2.048Mb/s, the first block of 32 locations of Data Memory reserved for the expansion bus are used. The 32
incoming channels on EST1 are placed in expansion block 1 of Data Memory. At 4.096 Mb/s the 64 bytes are
utilized in expansion block 1 and 2. At 8.192Mb/s all 128 locations of Data Memory reserved for the expansion
bus are used. Refer to the description of the memory allocation in Section 5, “Address Memory Map”.
This mode allows linking larger matrices of MT90812 devices together. For example, at 2.048 Mb/s, eight
MT90812 devices can be connected together via a MT8980D (DX) switch, as shown in Fig. 5.
8
channel
EST0/1
STi/o1
Local TDM Streams
Expansion Bus
TDM Link Mode
TRUNKS
AND PORTS
TRUNK S
AND PORTS
TRUNKS
AND PORTS
F0i
Figure 5 - Eight IDX Configuration using Expansion Bus TDM Link mode
E1
A1
i
E2
STi/o0-1
STi/o0-1
STi/o0-1
IDXb
IDXa
IDXh
E3
E4
EST0
uport
EST1
EST0
EST0
EST1
uport
EST1
uport
Figure 4 - Expansion Bus (TDM Link mode)
E5
A2
frame n
E6
E7
E8
MPU
. . .
. . .
-Law or
uport
DX
Advance Information
Law as defined in Control
i+32
E128