Datasheet

TUSB7320, TUSB7340
www.ti.com SLLSE76E–MARCH 2011– REVISED JULY 2011
10.4 Power Management Event (PME)
Power Management Events are generated by Functions as a means of requesting a PM state change.
Power Management Events are typically utilized to revive the system or an individual Function from a low
power state.
Before using any wakeup mechanism, a Function must be enabled by software to do so by setting the
PME_EN bit in the PMCSR, see Section 4.25. The PME_Status bit is sticky, and the value of the
PME_Status bit is maintained through reset if aux power is available and the device is enabled for wakeup
events.
10.4.1 PME Support
The 5-bit PME_support field in the PMC (Power Management Capabilities) register, Section 4.24,
indicates the power states in which the TUSB73X0 may send a PME Message. A value of 0b for any bit
indicates that it is not capable of sending PME Message while in that power state. Note that the default
value of the Bit15 of the PME_support for D3cold is "HwInit" and depends on the AUX_DET pin strapping.
If the AUX_DET is pulled high, bit 15 set to 1b.
Table 10-3. PME Support
Pin Name Support Wake from D3cold/D3hot Support Wake from D3hot only
3.3V Power rails must be maintained to support D3cold and Power rails must be maintained to support D3hot states,
1.1V D3hot states. but may be removed for D3cold.
Pulled high.When AUXDET is pulled high, bit 15 of the Pulled low. When AUXDET is pulled low, bit 15 of the
AUX_DET
Power Management Capabilities register is set to 1b. Power Management Capabilities register is cleared, or 0b.
Must not be asserted during D3cold and D3hot states
Must not be asserted during D3hot state, but should assert
GRST# for WAKE# to function correctly. Should be asserted if
if power rails fall below specified operating conditions.
power rails fall below specified operating conditions.
Connected to WAKE# of the system chipset and is
pulled high on the system board. WAKE# is used for WAKE# is not used. In band PME message is used for
WAKE#
wakeup from D3cold. In band PME message is used wakeup from D3hot.
for wakeup from D3hot.
Connected to CLKREQ# of the system chipset and is Connected to CLKREQ# of the system chipset and is
CLKREQ#
pulled high. pulled high.
Must remain pulled high during D3cold and D3hot Must remain pulled high during D3hot state. Should not be
OVERCUR(X:1)#
states. Should not be pulled high if power is removed. pulled high if power is removed.
If an EEPROM is used for configuration, power should also be maintained during D3cold and D3hot
states.
The assertion of PERST# transitions the TUSB7340 from D3hot to D3cold. PERST# must be asserted if
the power rails fall below the specified operation conditions.
Copyright © 2011, Texas Instruments Incorporated PCI EXPRESS POWER MANAGEMENT 105
Submit Documentation Feedback
Product Folder Link(s): TUSB7320 TUSB7340