mt90224 Zarlink Semiconductor, mt90224 Datasheet - Page 34

• Manufacturer Part Number: mt90224
• Description: 8-port Ima/tc Phy Device
• Manufacturer: Zarlink Semiconductor

2.2
The Transmit Convergence (TC) function is common for both the IMA and TC modes. It integrates the circuitry to
support ATM cell payload scrambling, HEC generation and the generation of Idle/Filler/ICP cells for use with the
T1/E1/J1 or DSL trunks. Each of the available ATM TC circuits can use the polynomial X
cell payload field. The MT90222/3/4 ATM cell payload scrambling function can be disabled.
The ITU I.432 polynomial X
Forum polynomial X
polynomial can be disabled. The resulting calculation is then written on the HEC field and the ATM cell is ready (i.e.,
complies with the IMA transmit protocol) for transmission over the flexible TDM Interface.
In cases where the TC block requests a cell to be transferred to any of the serial interfaces and the TX UTOPIA
FIFO has no cell ready for transmission, then the TC block will automatically send an IDLE cell (in TC mode) or a
Filler cell (in IMA mode) to the line. The default values for the Idle and the Filler cells comply with the ATM IMA
ATM In
The ATM Transmission Convergence
from IDCR Generator
Micro I/F
UTOPIA L2
Interface
Control
Cell In
Figure 5 - MT90224 Functional Block Diagram -Transmitter in IMA Mode
6
+ X
4
8
+ X
+ X
2
2
+ X + 1 is used to generate the HEC field of the ATM cell. By default, the ATM
+ 1 is added to the calculated HEC octet. The addition of the ATM Forum
Filler Cell
Idle Cell
ICP Cell Group 0
ICP Cell Group 1
ICP Cell Group 7
Next ICP Cell Group 0
Next ICP Cell Group 1
Next ICP Cell Group 7
ICP Cell Buffer RAM
TX Utopia FIFO
TX Utopia FIFO
FIFO Link 15
(see Note 1)
(see Note 1)
(see Note 1)
FIFO Link 0
FIFO Link 1
Transmitter
Cell RAM
Group 0
Group 7
Zarlink Semiconductor Inc.
MT90222/3/4
to Cell_In_Control
Round Robin Scheduler
and Adaptive Shaper
and FIFO Selection
34
ICP Cell Mod. and
ICP Cell Mod. and
ICP Cell Mod. and
Cell Scrambling
Cell Scrambling
Cell Scrambling
(1 of 8)
ICP Cell Handler
IDCR Generator
Transmitter
Link Timing
Reference
Note 1: This FIFO is the
TX UTOPIA FIFO when
the link is configured in
non-IMA Mode and it is the
TX LINK FIFO when it is
configured in IMA Mode
Note 2: In MT90222 groups
0,1,2,3 should be used.
(1 of 8)
43
To RX Block
+ 1 to scramble the ATM
TDM RING
Control
P/S
P/S
P/S
Data Sheet
Streams
Serial
TDM Ring
Link 15
From
Link 0
Link 1