T8207 Datasheet, PDF (47/158 Pages) Agere Systems – ATM Interconnect

Advance Data Sheet
September 2001
CelXpres T8207
ATM Interconnect
9 UTOPIA Interface (continued)
9.4 55-Byte UTOPIA Mode
In this special UTOPIA mode, the T8207 transmits a 55-byte cell, as opposed to 53 bytes, on the UTOPIA bus. The
extra 2 bytes are the tandem routing header received with the cell from the cell bus. These 2 bytes are appended
to the beginning of the cell with the tandem routing header [15:8] byte first, followed by the tandem routing header
[7:0] byte. Clearing the sp_utopia_sel* bit in the main configuration 1 register (address 0100h) enables this mode.
The start of cell signal (u_txsoc) is asserted only once with the first tandem routing header byte. The T8207 may be
configured for 55-byte UTOPIA mode whether it is an ATM or PHY device.
EXTERNAL
SDRAM
SDRAM
CONTROLLER
QUEUE FILL
MANAGER
EFCI
INSERTION
FECN ENA
QUEUE 0
TX UTOPIA
CELL BUFFER
(2 CELLS)
QUEUE 1
TX UTOPIA
CELL BUFFER
(2 CELLS)
HEC
INSERTION
53-byte CELL TO TX UTOPIA
QUEUE 62
TX UTOPIA
CELL BUFFER
(2 CELLS)
QUEUE 63
TX UTOPIA
CELL BUFFER
(2 CELLS)
Figure 12. TX UTOPIA Cell Handling
5-7783aF
Agere Systems Inc.
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