MPC8280 datasheet(1213/1386 Pages) FREESCALE

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Inverse Multiplexing for ATM (IMA)

MPC8280 PowerQUICC II Family Reference Manual, Rev. 1

Freescale Semiconductor

34-67

34.5.4.11 Test Pattern Procedure

Test patterns are used verify “connectivity” of a link in a particular group. The NE will request, via an ICP

cell, that a test pattern be looped back to the FE over all links currently in the group. For this test, the FE

will look only at ICP cells received over the link being tested (LID = x) and upon receiving an ICP cell

“echo” the pattern back to the NE over all the links in the group. The major task of initiating and verifying

the pattern on all the links in the group falls on the software. The MPC8280 will simply transmit and

receive the modified/changed ICP cells. If the software detects that the pattern was “echoed” by the FE,

then connectivity is verified.

34.5.4.11.1

As Initiator (NE)

Alter the (unused) ICP cell template to the “Test Link” command to the FE:

1. Tx Test Control = Set to “Active” and select LID (link) to be tested.

2. Tx Pattern = X (0-255).

3. Increment SCCI.

4. Make this the active ICP template (see Section 34.5.4.1, “Transmit ICP Cell Signalling”).

5. Repeat steps 1-4 until expected pattern is received in any of the incoming ICP cells (alternate ICP

templates must be used).

After sending the request to perform the test (pattern) to the FE, the NE software must wait for the TX test

pattern to be echoed back/received in the RX Pattern field of the ICP cell (any of the active links in the

group can be monitored for the RX Pattern). After verifying connectivity, the test can be de-activated (set

Tx Test Control = “Inactive” and repeat steps 3 and 4 above).

34.5.4.11.2

As Responder (FE)

When the FE receives a request to perform the “pattern” test on any of the active links, it must monitor the

selected link (see Tx LID of Tx Test Control) for reception of an ICP cell. Upon receiving an ICP cell

(remember, the other end is incrementing the SCCI field), the software should copy the Tx Pattern to the

Rx Pattern field of the ICP Cell and transmit the ICP cell. Alter the ICP cell:

1. Rx Pattern = Tx Pattern (of received ICP Cell).

2. Increment SCCI

3. Make this the active ICP template (see Section 34.5.4.1, “Transmit ICP Cell Signalling”).

4. Repeat steps 1-3 until the test is inactive.

There are two ways to monitor the link under test. The first method is to simply look for the expected LID

in the received ICP cells (ICP cell buffer). For this to happen, all links in the group must have MON_ICP

bit set:

Monitor link for changes in SCCI: ILRCNTL[MON_ICP] = 1.

Now, since changed ICP cells are passed to the ICP buffer only when the SCCI field changes, then it may

take some time for the link under test to pass on an ICP cell. Again, ICP cells will be passed on to the buffer

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