Motorola PowerQUICC II MPC8280 Series Reference Manual page 1271

34.5.4 IMA Software Procedures
The following procedures must be followed in order to assure the synchronization of
changes between the link state machines and the group state machine. Issues to be
considered are order of changes to the ICP cell and pointer, group order structure and
pointer, IMA PHY assignment structure, and group/link Tx control fields.
34.5.4.1 Transmit ICP Cell Signalling
1. Copy the transmit ICP cell template currently in use (as indicated by TICPPTR) to
the ICP cell template area not in use.
2. In the new template, change the ICP cell template fields as appropriate.
3. Verify that the IGTCNTL[ICPC] equals IGTSTATE[ICPCA]. If not, wait until it
does.
4. Change TICPPTR to point to the "changed/altered" (see step 1) ICP cell template.
5. Toggle IGTCNTL[ICPC].
34.5.4.2 Receive Link Start-up Procedure
Before "activation" of links and group can take place, ICP cells must be received and
processed by the management software. Software must configure all IMA links to "group
unassigned" mode. Reception of ICP cells requires that the corresponding PHYs (i.e., links)
have been enabled and the corresponding connection table entry/entries initialized (see
RXPHYEN, IMAPHYEN, and RICPH). In "group unassigned" mode, the first received
ICP cell will always be reported to the corresponding channel's buffer (RICPCH) and
subsequently every time there is a change in the SCCI (Status and Control Change
Indication) field of the ICP cell.
• Set ILRCNTL[GA] to 0 (zero).
Setting GA to zero (group unassigned) allows only ICP cells to be processed, all other cells
are dropped. The management software will analyze the ICP cells and program the
corresponding IMA Link Receive Table parameters:
• IMA Link ID (ILID)
• Link ICP offset (LICPOS)
• Select link as the Timing Reference Link (only one link can be TRL).
ILRCNTL[TRL] = 1.
• Assign the link to a group. ILRCNTL[IGNUM] = x.
• Verify size of frame (M) is the expected value.
The software must have built in knowledge of the mapping between physical links and their
corresponding channel number (e.g., PHY 0 uses channel 2 (RICPH = 2)). Once a group
has been established, the user can have all links in a group report changed ICP cells to a
MOTOROLA
Freescale Semiconductor, Inc.
Chapter 34. Inverse Multiplexing for ATM (IMA)
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IMA Software Interface and Requirements
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