MT90225AG Zarlink Semiconductor, MT90225AG Datasheet - Page 28

• Manufacturer Part Number: MT90225AG
• Description: Description = 16 Port TC PHY For T1, E1 And DSL ;; Package Type = N/a ;; No. Of Pins =
• Manufacturer: Zarlink Semiconductor

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Fractional T1/E1 and nx64 channel modes are implemented by programming bits in the mapping registers to enable
the use of the required time slots.
4.1.1 Single mode - Generic 1.544MHz
This is also known as T1 generic mode. In this mode, data rate is 1.544 Mb/s, clock is 1.544 MHz and frame pulse
is 8 KHz. A frame is 193 bits long and a frame pulse is present (either generated or accepted as input). The first bit,
indicated by the frame pulse, is not used to carry any useful information; it is in high impedance on Tx link and is
ignored on Rx link. The 24 time slots (192 bits) are controlled by the lowest 24 bits of the mapping register associated
with a link. Fractional T1 is supported by activating (selecting) any of the first 24 time slots defined in the mapping
register.
This mode is selected in TDM TX Link Control (0x0600-0x060F) and TDM RX Link Control (0x0700-0x070F) by
the following settings.
4.1.2 Single mode - Generic 2.048MHz
This is used for generic nx64 connections, where n can be any number from 1 to 32. In this mode, data rate is 2.048
Mb/s. A clock of 2.048 MHz is used and the Frame pulse is indicating the first bit of the first time slot of a frame of
32 time slots. The mapping registers are used to determine the number of time slots used and their position in the
frame. This enables a direct interface to existing T1 or E1 framers and opens up the option to interface to generic
nx64 devices. Fractional T1/E1 is supported as well by selecting the time slots that are used to carry ATM traffic.
Note: Both frame pulse polarity and clock edge are programmable.
Data rate (bits 6:5) = 00
Multiplex mode (bits 4:3) = 00
Clock and Sync format (bit 2) = 0
Cell delineation mode (bit 10 of TDM RX Link Control only) = 0
T1 Frame
Bit Cells
at DSTx0-15
Serial Bit
Stream
TXSYNC
TXCK
RXSYNC
RXCK
Figure 8 - Single mode - Generic 1.544 MHz
Bit Cell
bit 193
Zarlink Semiconductor Inc.
High Impedance
Unused or
bit 1
Bit Cell
bit 2
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Data Sheet