MT92220BG Zarlink Semiconductor, MT92220BG Datasheet - Page 160

• Manufacturer Part Number: MT92220BG
• Description: Description = 1023 Channel Voice Over IP/AAL2 Processor ;; Package Type = Epbga ;; No. Of Pins = 608
• Manufacturer: Zarlink Semiconductor

MT92220
Data Sheet
11.3
Polarities
There are a few exceptions, however. The sclk and sclkx2 signals can be programmed to have their polarities
identical to those defined in the H.110 specification, or they can have the opposite polarity. In some cases their
rising edges will coincide with the rising edge of ct_c8 , and in some cases will coincide with falling edges. In
addition, the frequency of sclk can be programmed to 2, 4 or 8 MHz, with sclkx2 being generated in function of this
(note that when sclk is 8 MHz, sclkx2 is also 8 MHz but off-shifted by a quarter-period. For more details on
expected polarity, see H.110 specification). The fr_comp signal can also be generated active-high or active-low,
can be generated as coinciding with a clock edge or as straddling it, and can be generated as relating to a clock at
2 MHz, 4 MHz or 8 MHz.
As mentioned earlier, H.110 requires that the lower 16 streams on the bus be capable of running at 2 or 4 MHz, with
a single clock frequency determined for each group of 4 streams. The MT92220 allows every group of 4 streams on
the bus to operate at 2, 4 or 8 MHz, allowing all 32 streams to be used in backwards compatibility with another
non-H.110 agent.
In addition, the MT92220, instead of supporting the full bandwidth of H.110, can be configured to only interface with
4, 8 or 16 of the streams on the bus. This allows the chip to be run at a much lower frequency than 60 MHz.
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Zarlink Semiconductor Inc.