ZL30226/GA ZARLINK [Zarlink Semiconductor Inc], ZL30226/GA Datasheet - Page 52

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

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3.3.15
The ZL30226/7/8 supports software controlled link addition to an existing RX link group. Such an addition can be
used to increase available bandwidth. The added link receives Filler cells until the Far End (FE) TX side is active.
During this time, the new link’s delay is measured and compared with the current operating limits. The link is either
rejected or accepted. The operational delay can be corrected if required as described in 3.3.13.6
Incrementing/Decrementing the Recombiner Delay. After synchronization is achieved, the added link can be
included in the recombiner algorithm using bit 4 or 12 of the RX Recombiner (0x0201-0x0208) register. The link will
be effectively included in the IMA Group when the corresponding bit in the Enable Recombiner Status (0x02AD)
register is set.
A link may also be added to an IMA Group when the first User cell is received. This is done by writing to the RX
Recombiner Delay Control (0x0283) register.
3.3.16
There are two reasons to deactivate a link:
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Both link deactivation procedures specified in the IMA specification are supported under the control of software.
The command to disable the recombination process for a link is issued by writing to bit 4 or 12 of the RX
Recombiner (0x0201-0x0208) register.
If the delay of the link to be removed is not the worst delay, then no pointer correction is required and the
recombiner bit (i.e., bit 4 or 12 of RX Recombiner (0x0201-0x0208) register) for the removed link should be set to
0.
If it is the worst case delay, then the pointer values could be corrected to reduce the amount of additional delay
introduced by the recombiner. To do this, the pointers need to be changed (advanced). This results in reducing the
number of cells (the amount of time) required for the recombiner process.
To reduce the impact of this correction, its implementation can either be immediate or delayed. A command in the
Increment Delay Control (0x0281) or Decrement Delay Control (0x0282) register is used for this purpose (refer
to 3.3.13.6 Incrementing/Decrementing the Recombiner Delay, for more details).
3.3.17
Before an IMA Group can be disabled, the software should ensure that no User cells are left in memory. As part of
the higher level handshaking, the TX FE should have sent Filler cells for a while for the RX side to process all the
User cells that could be in the external memory.
The procedure to follow is to stop the recombination process and then wait for the enable process to be reported
inactive (in the Enable Recombiner Status (0x02AD) register) before re-assigning the link to another IMA group or
to TC Mode.
Write to the RX Link Control (0x00C0-0x00C7) register to select the RX options
Configure the RX serial port(s) by writing to the TDM RX Link Control (0x0700-0x070F) register
Configure the RX IMA UTOPIA port by writing to the UTOPIA Output Group PHY Enable (0x0011) and
UTOPIA Output Group Address (0x0008-0x000B) registers
Validate the IMA parameter values received over the TDM links and configure the link in IMA mode using the
RX Recombiner (0x0201-0x0208) and the RX Link Control (0x00C0 - 0x00C7) register
When ready, start the recombiner process by writing to the RX Recombiner (0x0201-0x0208) register
the bandwidth required decreases or
an existing link becomes faulty.
Link Addition
Link Deletion
Disabling an IMA Group
Zarlink Semiconductor Inc.
ZL30226/7/8
52
Data Sheet