MT90870AG Zarlink, MT90870AG Datasheet - Page 22

• Manufacturer Part Number: MT90870AG
• Description: Switch Fabric 12K x 12K/8K x 4K 1.8V/3.3V 272-Pin BGA Tray
• Manufacturer: Zarlink

Specifications of MT90870AG

• Package: 272BGA
• Number Of Ports: 32
• Fabric Size: 12K x 12K|8K x 4K
• Switch Core: Non-Blocking|Blocking
• Port Speed: 2.048|4.096|8.192|16.384 Mbps
• Operating Supply Voltage: 1.8|3.3 V

2.2.1.2
The bit rate for each output stream is selected by writing to a dedicated Local Output Bit Rate Register (LOBRR0-
15). Refer to Table 43, Local Output Bit Rate Register (LOBRRn) Bits.
Operation of stream data in the Connection Mode or the Message Mode is determined by the state of the LMM bit,
and the channel High-impedance state is controlled by the LE bit of the Local Connection Memory. The data source
(i.e. from the Local or Backplane Data Memory) is determined by the LSRC bit of the Local Connection Memory.
Refer to Section 6.1, Local Connection Memory, and Section 12.3, Local Connection Memory Bit Definition.
2.2.2
The Backplane streams may be operated in one of two modes, namely Non-32 Mb/s Mode and 32 Mb/s Mode. The
Local stream data-rates are not affected by the operating mode of the Backplane. The operating mode of the
Backplane is determined by setting the Control Register bit, MODE32. Setting the bit HIGH will invoke the 32 Mb/s
Mode. Setting the bit LOW will invoke the Non-32 Mb/s mode. The default bit value on device Reset is LOW. The
timing of the input and output clocks and frame pulses are shown in Figure 7, Backplane Port Timing Diagram for 2,
4, 8, 16 and 32 Mb/s stream rates.
Non-32 Mb/s Mode: Each of the 32 Backplane streams (BSTi0-31 and BSTo0-31) and Local streams (LSTi0-15 and
LSTo0-15) can be independently programmed for a data-rate of 2.048 Mb/s, 4.096 Mb/s, 8.192 Mb/s or
16.384 Mb/s.
32 Mb/s Mode: 16 of the Backplane input streams (BSTi0-15) and 16 Backplane output (BSTo0-15) streams
operate at a fixed rate of 32.768 Mb/s. In this mode, the upper 16 input (BSTi16-31) and 16 output (BSTi16-31)
streams are unused. All 32 Local streams can be independently programmed for a data-rate of 2.048 Mb/s,
4.096 Mb/s, 8.192 Mb/s or 16.384 Mb/s.
2.2.2.1
The bit rate for each input stream is selected by writing to a dedicated Backplane Input Bit Rate Register (BOBRR0-
31). Refer to Table 45, Backplane Input Bit Rate Register (BIBRRn) Bits. If the 32 Mb/s mode is selected by writing
to the Control Register bit (MODE32), the settings in BIBRRn are ignored.
2.2.2.2
The bit rate for each output stream is selected by writing to a dedicated Backplane Output Bit Rate Register
(BOBRR0-31). Refer to Table 47, Backplane Output Bit Rate Register (BOBRRn) Bits. If the 32 Mb/s mode is
selected by writing to the Control Register bit (MODE32), the settings in BOBRRn are ignored.
Operation of stream data in the Connection Mode or the Message Mode is determined by the state of the BMM bit,
and the channel High-impedance state is controlled by the BE bit of the Backplane Connection Memory. The data
source (i.e., from the Local or Backplane Data Memory) is determined by the BSRC bit of the Backplane
Connection Memory. Refer to Section
Connection Memory Bit Definition.
Backplane Port Rate Selection
Local Output Port
Backplane Input Port
Backplane Output Port
6.2, Backplane Connection Memory and Section
Zarlink Semiconductor Inc.
MT90870
22
12.4, Backplane
Data Sheet