MT90222AG Zarlink Semiconductor, MT90222AG Datasheet - Page 41

• Manufacturer Part Number: MT90222AG
• Description: Description = 4 Port Ima & TC PHY For T1, E1 And DSL ;; Package Type = N/a ;; No. Of Pins =
• Manufacturer: Zarlink Semiconductor

2.4.9
The content of the Filler cell is pre-initialized and conforms with the IMA Specification. The OAM label in the Filler
Cell is copied from the ICP cell, allowing both IMA 1.0 and IMA 1.1 to run simultaneously on the same device.
2.4.10
Initialize the TX IMA Group start-up as follows:
(Note: The startup procedure below is given indicating the most important steps. A more detailed and complete
sequence can be found in the Zarlink IMA Core Software). For MT90222 only groups 0,1,2 and 3 are used.
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2.4.11
The MT90222/3/4 supports software controlled link addition to an existing IMA group. Link addition is used to
increase the available bandwidth. The TX Link Control registers (0x0318-0x031F), the TX Link ID
(0x0336-0x033D) and TX ICP Cell Offset (0x0310-0x0317) registers are initialized first with the proper IMA
Group information. The link is assigned to a TX IMA group by writing to bits 10:8 or bits 2:0 of the TX Link Control
(0x0318-0x031F) register. Before the TX link can be configured in IMA mode, the value of 0x108 + group number
has to be written in the TX Add Link Control Register (0x0333). The link is then configured in IMA mode by
writing to the bit 3 or 11 of the TX Link Control (0x0318-0x031F) register. The TX IMA Mode Status (0x0346)
register is monitored to detect when the link is reported in IMA mode. TX Link control (0x0318-0x031F) register bit
6 or 14 determines when ATM User cells can be sent. Then the bit 3 of the TX Add Link Control Register
(0x0333) is written with 0x0100.
2.4.12
There are two reasons to remove a link: the required bandwidth decreases or a link becomes faulty. The
MT90222/3/4 supports link deactivation under software control.
A link stops transmitting User cells when bit 6 or 14 of the TX Link Control register (0x0318-0x031F) is set to 0.
Filler and ICP cells will still be sent on the link. The link is removed from an IMA group by first setting bit 3 or 11 of
the TX Link Control register (0x0318-0x031F) to 1 while keeping the original IMA group number. The IMA group
number can be changed only when the link is in TC mode as reported in the TX IMA Mode Status register
(0x0346). It then can be assigned to another IMA group.
When removing the last link of a TX IMA group, the TX UTOPIA FIFO has to be empty. This can easily be done by
first disabling the source of ATM cells (ATM Utopia controller), then disabling the TX IMA UTOPIA Port using the
UTOPIA Input Link PHY Enable (0x0050) or UTOPIA Input Group PHY Enable (0x0051) registers while still
keeping the "Send User Cell" bit of the TX Link Control (0x0318-0x031F) register set to 1. The above procedure
can then be applied to assign the link in TC mode.
Configure the TX TDM port(s) by writing to the TDM TX Link Control (0x0600-0x060F) registers.
Write the value of M, the Timing Mode and the reference link number to the TX Group Control Mode
(0x0300-0x0307) register corresponding to the IMA Group number to be initialized.
Write the Link ID (LID is between 0-31) to TX Link ID (0x0336-0x033D) registers for each link to be used in
the IMA Group. LID should not be changed when a group is operational. Ensure each link that is part of an
IMA group has a unique LID (note that the MT90222/3/4 does not verify LIDs).
Write the ICP Cell Offset value to TX ICP Cell Offset (0x0310-0x0317) registers. This value depends on the
value of M. Typically, the reference link will have a delay of 0 cells in the IMA Frame and the ICP cell in each
other link will be evenly spaced in a multiple of M/N cells (where M is defined in the IMA specification and N
is the number of links). The offset value for an operational group should not be changed.
Write to the TX Link Control (0x0318-0x031F) registers to put the link(s) in IMA mode and to enable the
transfer of ATM User Cells when required.
Filler Cell Definition
TX Link Addition
TX IMA Group Start-Up
TX Link Deletion
Zarlink Semiconductor Inc.
MT90222/3/4
41
Data Sheet