Power Management
The BIOS supports the Advanced Configuration and Power Management Interface (ACPI) 3.0 specification. A key feature of ACPI is that the operating system, not the BIOS, configures and implements power management. The 7611 terminal supports the Global system power states defined by ACPI:
G3 Mechanical Off
A computer state that is entered and left by a mechanical means.
Example: Turning off the system's power through the movement of a large red switch.
Various government agencies and countries require this operating mode. It is implied by the entry of this off state through a mechanical means that no electrical current is running through the circuitry and that it can be worked on without damaging the hardware or endangering service personnel. The OS must be restarted to return to the Working state. No hardware context is retained. Except for the real-time clock, power consumption is zero.
G2/S5 Soft Off
A computer state where the computer consumes a minimal amount of power. No user mode or system mode code is run. This state requires a large latency in order to return to the Working state. The system's context will not be preserved by the hardware. The system must be restarted to return to the Working state. It is not safe to disassemble the machine in this state.
G1 Sleeping
A computer state where the computer consumes a small amount of power, user mode threads are not being executed, and the system appears to be off (from an end user's perspective, the display is off, and so on). Latency for returning to the Working state varies on the wake environment selected prior to entry of this state (for example, whether the system should answer phone calls). Work can be resumed without rebooting the OS because large elements of system context are saved by the hardware and the rest by system software. It is not safe to disassemble the machine in this state.
G0 Working
A computer state where the system dispatches user mode (application) threads and they execute. In this state, peripheral devices (peripherals) are having their power state changed dynamically. The user can select, through some UI, various performance/power characteristics of the system to have the software optimize for performance or battery life. The system responds to external events in real time. It is not safe to disassemble the machine in this state.
ACPI Sleep States (S0 - S5)
Under the G1 sleeping state ACPI defines levels of system sleep state support. The 7600 supports the following sleeping states:
•S0: Normal Powered-On state
•S1 (Standby): The S1 sleeping state is a low wake latency sleeping state. In this state, no system context is lost (CPU or chip set) and hardware maintains all system contexts.
Note: The 7600 does not support S1 state. Turning off the backlight and hard drives provides the equivalent power savings (due to Intel's processor C-states feature) at nearly zero latency.
•S2: Not supported
•S3 (Suspend to Ram): The S3 sleeping state is a low wake latency sleeping state. This state is similar to the S1 sleeping state except that the CPU and system cache context is lost (the OS is responsible for maintaining the caches and CPU context). Control starts from the processor's reset vector after the wake event. In NCR systems, during S3, power is only provided to the on-board USB ports.
Note: When the terminal resumes from an S3 state, all the USB devices re-enumerate. This causes speaker tones as if they were disconnected and then reconnected. This does not present a problem and the USB devices will continue to operate correctly.
Requirements for S3 support:
•O/S must be built on a system with S3 enabled in the BIOS
•Some peripherals may not be S3 capable, which can prevent the system from entering S3 state.
• "S4 (Suspend to Disk): The S4 state is the lowest power, longest wake latency sleeping state supported by ACPI. In order to reduce power to a minimum, it is assumed that the hardware platform has powered off all devices. Platform context is maintained.
Requirements for S4 support:
•O/S must be built on a system with S3 enabled in the BIOS
•Some peripherals may not be S4 capable, which can prevent the system from entering S4 state.
Reference the ACPI Specification for details.
Peripherals: ACPI defines power states for peripherals which are separate from the system power state. The device power states range from D0 (fully-on) to D3 (off) It is the responsibility of the driver developer for each peripheral to define and support the available power states.
|
Power State |
||||||
|---|---|---|---|---|---|---|
|
S0Working |
S1Standby |
S2 |
**S3 Suspend to RAM |
S4Hibernate |
**S5Soft Off |
|
|
Supported |
Y |
Y |
N |
Y |
Y |
Y |
|
Description |
Fully Functional |
•Video Back Light Off •HDD Off •Cache Flush • Memory in Slow Refresh •CPU Halted |
•Video Back Light Off •HDD Off •Cache Flush • Memory in Slow Refresh •CPU Halted |
•Video Back Light Off •HDD Off •Cache Flush • Memory in Slow Refresh •CPU Halted |
OFF |
|
|
Power Supply Status |
On |
On |
|
Powered Down** |
Powered Down** |
Powered Down** |
|
Power Consumption* |
37 |
24 |
|
2 |
1 |
<1 |
|
Wake Options |
||||||
|
Power Switch |
N/A |
Y |
Y |
Y |
Y |
|
|
PS/2 Keyboard |
N/A |
Y |
Y |
N |
N |
|
|
PS/2 Mouse |
N/A |
Y |
Y |
N |
N |
|
|
USB Keyboard |
N/A |
Y |
Per O/S |
N |
N |
|
|
USB Mouse |
N/A |
Y |
Per O/S |
N |
N |
|
|
LAN (magic packet) |
N/A |
Y |
Y |
Y |
Y |
|
|
RTC Alarm |
N/A |
Y |
Y |
Y |
Y |
|
|
Serial Port (RI) |
N/A |
Y |
N |
N |
N |
|
|
Note: Power consumption based on the following configuration with no peripherals Intel Atom 270, 512MB DIMM, HDD *Maintains small voltage to support wake circuits) **The external power supply is ON while in S3-S5. The motherboard shuts down all power circuits except for a small voltage to support wake circuits. Power to the 24V USB printer port and the Cash drawer is also disconnected while in S3-S5 |
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