
IDT Hot-Plug and Hot-Swap
PES48T12G2 User Manual
9 - 5
April 5, 2013
Notes
In addition to a port reset output being asserted as determined by the Reset Mode (RSTMODE) field, a
port reset output is also asserted under the following circumstances.
–
When the switch experiences a fundamental reset.
–
When the operating mode of a port is modified and the OMA field is set to reset.
Hardware ensures that the minimum port reset output assertion pulse width is no less than 200 µS.
Power Enable Controlled Reset Output
In this mode a downstream port reset output state is controlled as a side effect of slot power being
turned on or off. The operation of this mode is illustrated in Figure 9.4. A downstream port’s slot power is
controlled by the Power Controller Control (PCC) bit in the PCI Express Slot Control (PCIESCTL) register
Figure 9.4 Power Enable Controlled Reset Output Mode Operation
While slot power is disabled, the corresponding downstream port reset output is asserted.
When slot power is enabled by writing a zero to the PCC bit, the Port x Power Enable Output (PxPEP) is
asserted and then power to the slot is enabled and the corresponding downstream port reset output is
negated. The time between the assertion of the PxPEP signal and the negation of the PxRSTN signal is
controlled by the value in the Slot Power to Reset Negation (PWR2RST) field in the HPCFGCTL register.
While slot power is enabled, the corresponding downstream port reset output is negated.
When slot power is disabled by writing a one to the PCC bit, the corresponding downstream port reset
output is asserted and then slot power is disabled. The time between the assertion of the PxRSTN signal
and the negation of the PxPEP signal is controlled by the value in the Reset Negation to Slot Power
(RST2PWR) field in the HPCFGCTL register.
Power Good Controlled Reset Output
As in the Power Enable Controlled Reset mode, in this mode a downstream port reset output state is
controlled as a side effect of slot power being turned on or off. However, the timing in this mode depends on
the power good state of the slot’s power supply. The operation of this mode is illustrated in Figure 9.5.
Figure 9.5 Power Good Controlled Reset Output Mode Operation
PxPEP
PxRSTN
T
PWR2RST
T
RST2PWR
PxPEP
PxPWRGDN
T
PWR2RST
PxRSTN
T
RST2PWR
Summary of Contents for 89HPES48T12G2
Page 14: ...IDT Table of Contents PES48T12G2 User Manual vi April 5 2013 Notes...
Page 22: ...IDT Register List PES48T12G2 User Manual xiv April 5 2013 Notes...
Page 38: ...IDT PES48T12G2 Device Overview PES48T12G2 User Manual 1 16 April 5 2013 Notes...
Page 64: ...IDT Reset and Initialization PES48T12G2 User Manual 5 8 April 5 2013 Notes...
Page 82: ...IDT Link Operation PES48T12G2 User Manual 6 18 April 5 2013 Notes...
Page 98: ...IDT SerDes PES48T12G2 User Manual 7 16 April 5 2013 Notes...
Page 118: ...IDT Theory of Operation PES48T12G2 User Manual 8 20 April 5 2013 Notes...
Page 152: ...IDT SMBus Interfaces PES48T12G2 User Manual 12 20 April 5 2013 Notes...
Page 158: ...IDT Multicast PES48T12G2 User Manual 13 6 April 5 2013 Notes...