Motorola PowerQUICC II MPC8280 Series Reference Manual page 1277

5. Software should wait (poll) for the MPC8280 to remove the link from the DCB
routine. The corresponding bit in the group table's LINK_DCB entry will be
cleared by the MPC8280 (IMA) (this means no more cells are being stored in the
DCB), e.g.,: while (LINK_DCB != REF_LINK).
6. Use the new group order table by inverting the current GOTP value:
IGRCNTL[GOTP] = x.
7. Indicate that this link is no longer assigned to a group: ILRCNTL[GA] = 0.
8. Inhibit reception of cells over dropped link in the IMA Root Table: RXPHYEN &=
~x (i.e., clear the corresponding link bit in the RXPHYEN entry). Note, you must
reenable (set to 1) the corresponding bit at a later point if you wish to use this link
as a non-IMA link.
9. Software should wait (poll) for the MPC8280 to be using the new group order
table. This simply ensures that it is safe to modify/re-use the dropped link
parameters (i.e., the MPC8280 is no longer using the dropped link's data
structures). Do this by making sure the group order pointer points to the new group
order table (at this point, no more cells are extracted out of the dropped link's
DCB), e.g.,: while (dcblink != new_pointer). DCBLINK is an entry in the IGRTE.
10. Indicate that this link is no longer an IMA Link in the IMA Root Table: IMAPHY
&= ~x (clear the bit). Note, in a symmetrical operation, this step should be the last
one performed (after both RX and TX have been disabled). Setting this bit
prematurely will halt transmission/reception on the corresponding link.
34.5.4.5.2 TX Parameters
1. Formulate new group order table with the "dropped" link excluded (see
Section 34.4.4.1.3, "Transmit Group Order Table").
2. Point to new TX Group Order Table in the corresponding IMA Group Transmit
Table Entry (IGTTE): TGRPORDER = New Table Offset.
3. Decrement the number of links in the group (IGTTE): TNUMLINKS -= 1.
4. Inhibit transmission of cells over dropped link in the IMA Root Table: TXPHYEN
&= ~x (i.e., clear the corresponding link bit in the TXPHYEN entry). Note, you
must reenable (set to 1) the corresponding bit at a later point if you wish to use this
link as a non-IMA link.
5. Indicate that this link is no longer an IMA Link in the IMA Root Table: IMAPHY
&= ~x (clear the bit). Note, in symmetrical operation, this step should be the last
one performed (after both RX and TX have been disabled). Setting this bit
prematurely will halt transmission/reception on the corresponding link.
MOTOROLA
Freescale Semiconductor, Inc.
Chapter 34. Inverse Multiplexing for ATM (IMA)
For More Information On This Product,
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IMA Software Interface and Requirements
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