IDT 89HPES64H16G2 User Manual page 83

IDT Switch Partitions
Notes
PES64H16G2 User Manual
A port in the disabled mode has the following behavior.
– All output signals associated with the port are placed in a negated state (e.g., link status and hot-
plug signals).
• The negated value of HPxAIN, HPxILOCKP, HPxPEP, HPxPIN, and HPxRSTN is determined as
shown in Table 10.2.
• PxACTIVEN and PxLINKUPN are negated.All input signals associated with the port are ignored
and have no effect on the operation of the device.
• Boot configuration vector signals are sampled during a switch fundamental reset and thus their
dynamic state has no effect on the operating mode of the port in any port mode.
For example, if the PxyMERGEN signal associated with the port was asserted during a switch
fundamental reset, then the port remains merged while disabled. The state of the following
port signals is ignored: HPxAPN, HPxMRLN, HPxPDN, HPxPFN, and HPxPWRGDN.
– Since a port in this state is not associated with a switch partition, the state of no switch partition
input signal (e.g., PARTxPERSTN) has effect on the port.
• Since the port is not associated with a switch partition in this state, the port is unaffected by the
state of any switch partition, and vice-versa.
1
• The LTSSM immediately transitions to the Detect state and SerDes lanes associated with the
port are turned off.
• Unused logic is placed in a low power state (e.g., clock is gated).
• All registers associated with the port remain accessible from the global address space.
• PCI configuration requests to the port registers are not possible.
Register state is preserved in the disabled state. Therefore, transitioning a port from an operational state
to a disabled state and then back to an operational state results in no change in register values except for
fields that report status. All configuration registers in all functions associated with the port are accessible
through the global address space by the serial EEPROM, other ports, and the SMBus.
In this mode, all registers in the PCI-to-PCI bridge are accessible and the register space is organized as
that shown in Table 15.4 for a downstream port. Register fields whose value is dependent on port mode are
configured to operate as a downstream port.
Unattached
An unattached port is a port not associated with a switch partition and except for the link, is not opera-
tional. A port in the unattached mode has the following behavior.
– The physical and data-link layers remain operational and the link behaves as an upstream port.
• The PxACTIVEN and PxLINKUPN signals are driven normally and reflect the state of the link.
• The LTSSM transitions and remains in the L0 state. If necessary, the link trains from the Detect
state.
• ASPM configuration and D-state power management is ignored.
The transaction layer functionality necessary to respond to configuration requests and manage flow
control remains active. All other logic associated with the port is disabled. For example, the port does not
generate power management messages, it does not generate INTx or MSI interrupts, and it does not
generate error messages.
All output signals associated with the port, except signals associated with the link, are placed in a
negated state.
– The negated value of HPxAIN, HPxILOCKP, HPxPEP, HPxPIN, and HPxRSTN is determined as
shown in Table 10.2.
– PxACTIVEN and PxLINKUPN are negated.
– The SerDes signals and link status and activity signals remain active.
1.
The term 'LTSSM' refers to a port's Link Training and Status State Machine in the Physical Layer.
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