ZL30226/GA ZARLINK [Zarlink Semiconductor Inc], ZL30226/GA Datasheet - Page 35

• Manufacturer Part Number: ZL30226/GA
• Description: 4/8/16 Port IMA/TC PHY Device for xDSL
• Manufacturer: ZARLINK [Zarlink Semiconductor Inc]

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
xDSL trunks. Each of the available ATM TC circuits can use the polynomial X
field. The ZL30226/7/8 ATM cell payload scrambling function can be disabled.
The ITU I.432 polynomial X
Forum polynomial X
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 Specification
and are pre-loaded in the ZL30226/7/8 following a reset. The TX Cell RAM Control (0x0080) register can be used
to re-initialize the TX Cell RAM.
ATM In
The ATM Transmission Convergence
from IDCR Generator
Micro I/F
UTOPIA L2
Interface
Control
Cell In
Figure 5 - ZL30228 Functional Block Diagram -Transmitter in IMA Mode
6
+ X
4
+ X
8
+ X
2
+ 1 is added to the calculated HEC octet. The addition of the ATM Forum polynomial
2
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
+ X + 1 is used to generate the HEC field of the ATM cell. By default, the ATM
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.
ZL30226/7/8
to Cell_In_Control
Round Robin Scheduler
and Adaptive Shaper
and FIFO Selection
35
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 ZL30226 groups
0,1,2 and 3 should be used.
(1 of 8)
43
+ 1 to scramble the ATM cell payload
To RX Block
TDM RING
Control
P/S
P/S
P/S
Data Sheet
Streams
Serial
TDM Ring
Link 15
Link 0
Link 1
From