
IDT Reset and Initialization
PES32NT24xG2 User Manual
3 - 12
January 30, 2013
Notes
–
A partition downstream secondary bus reset is only applicable to partitions with one or more down-
stream switch ports. This type of reset causes a hot reset to be propagated on the external link of
the corresponding downstream switch port.
The operation of the slave SMBus interface is unaffected by a partition reset. Using the slave SMBus to
access a register that is in the process of being reset causes the register’s default value to be returned on a
read and written data to be ignored on writes.
Partition Fundamental Reset
A partition fundamental reset is initiated by any of the following events.
–
A switch fundamental reset (refer to section Partition Resets on page 3-11).
–
Assertion of a partition fundamental reset signal.
–
As directed by the Switch Partition State (STATE) field in the Switch Partition (SWPARTxCTL)
register.
Associated with each partition is a partition fundamental reset input (PARTxPERSTN).
–
The partition fundamental reset input for the first four partitions (i.e., partitions zero through three)
are available as GPIO alternate functions.
–
The partition fundamental reset input for all partitions are available on external I/O expanders
(refer to section I/O Expanders on page 12-11).
When a partition fundamental reset is initiated, the following sequence of actions take place.
1. All logic associated with the switch partition (i.e., ports, switch core buffers, etc.) is logically reset to
its initial state.
2. All port links associated with the partition enter the ‘Detect’ state.
3. All registers and fields, except those designated as SWSticky, take on their initial value. The value
of SWSticky registers and fields is preserved across a partition fundamental reset.
4. As long as the condition that initiated the partition fundamental reset persists (e.g., the fundamental
reset signal is asserted or the STATE field remains set to reset), logic associated with the partition
remains at this step.
5. Ports associated with the partition begin to link train and normal partition operation begins.
Partition Hot Reset
A partition hot reset is initiated by any of the following events.
–
Reception of TS1 ordered-sets on the partition’s upstream port indicating a hot reset.
–
Data link layer of the partition’s upstream port indicates a DL_Down status. The only exception
case is a DL_Down caused by the upstream port’s link transitioning to L2/L3 Ready state (refer to
section Link States on page 7-9).
When a partition hot reset is initiated the following sequence of actions take place.
1. The upstream port associated with the partition transitions its PHY LTSSM state to the appropriate
state (i.e., the Hot Reset state on reception of TS1 ordered-sets indicating hot reset or else the
Detect state).
2. Each downstream switch port associated with the partition (if any) whose link is ‘up’ propagates a
hot reset by transmitting TS1 ordered sets with the hot reset bit set.
If the link associated with a downstream switch port is in the Disabled LTSSM state, then a hot
reset will not be propagated out on that port. The port will instead transition to the Detect LTSSM
state. Although this is not technically a hot reset, this has the same functional effect on downstream
Содержание PCI Express 89HPES32NT24xG2
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Страница 24: ...IDT List of Tables PES32NT24xG2 User Manual xiv January 30 2013 Notes...
Страница 28: ...IDT List of Figures PES32NT24xG2 User Manual xviii January 30 2013 Notes...
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Страница 244: ...IDT SMBus Interfaces PES32NT24xG2 User Manual 12 40 January 30 2013 Notes...
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Страница 492: ...IDT Proprietary Port Specific Registers PES32NT24xG2 User Manual 21 44 January 30 2013 Notes...
Страница 588: ...IDT NT Endpoint Registers PES32NT24xG2 User Manual 22 96 January 30 2013 Notes...
Страница 710: ...IDT JTAG Boundary Scan PES32NT24xG2 User Manual 25 12 January 30 2013 Notes...
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