HP (Hewlett-Packard) D315 用户手册

Technical Reference Guide 

  

 
The power supply assembly is controlled digitally by the PS On signal (Figure 7-1). When PS On 
is asserted, the Power Supply Assembly is activated and all voltage outputs are produced. When 
PS On is de-asserted, the Power Supply Assembly is off and all voltages (except +5 AUX) are not 
generated. Note that the +5 AUX voltage is always produced as long as the system is 
connected to a live AC source.  
 

 
The PS On signal is typically controlled through the Power Button which, when pressed and 
released, applies a negative (grounding) pulse to the power control logic. The resultant action of 
pressing the power button depends on the state and mode of the system at that time and is 
described as follows: 

 

Off 

Negative pulse, of which the falling edge results in power control logic asserting PS 
On signal to Power Supply Assembly, which then initializes. ACPI four-second 
counter is not active. 

On, ACPI Disabled 

Negative pulse, of which the falling edge causes power control logic to de-assert the 

 active. 

PS On signal. ACPI four-second counter is not

On, ACPI Enabled 

Pressed and Released Under Four Seconds:  
       Negative pulse, of which the falling edge causes power control logic to  

us, 

       generate SMI-, set a bit in the SMI source register, set a bit for button stat
       and start four-second counter. Software should clear the button status bit 

s  

       within four seconds and the Suspend state is entered.  If the status bit i
       not cleared by software in four seconds PS On is de-asserted and the  

mbly shuts down (this operation is meant as a guard if 

       power supply asse

      the OS is hung).  

 
 
Pressed and Held At least Four Seconds Before Release: 

nds and then released,  PS On is 

       If the button is held in for at least four seco
       negated, de-activating the power supply.   

 
 

 

 

7-3