IDT 89HPES24N3A, User Manual

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IDT Link Operation
PES24N3A User Manual 4 - 7 April 10, 2008
Notes
Link Status
Associated with each port is a Port Link Up (PxLINKUP) status output and a Port Activity (PxACTIVE)
status output. These outputs are provided on I/O Expander 4. See section I/O Expanders on page 6-6 for
the operation of the I/O expander and the mapping of these status outputs to I/O expander pins.
The PxLINKUP and PxACTIVE status outputs may be used to provide a visual indication of system state
and activity or for debug. The PxLINKUP output is asserted when the PCI Express data link layer is up (i.e.,
when the LTSSM is in the L0, L0s, L1, or recovery states). When the data link layer is down, this output is
negated.
The PxACTIVE output is asserted whenever any TLP, other than a vendor defined message, is trans-
mitted or received on the corresponding port’s link. Whenever a PxACTIVE output is asserted, it remains
asserted for at least 200 ms. Since an I/O expander output may change no more frequently than once every
40 ms, this translates into five I/O expander update periods.