ACPI (Advanced Configuration and Power Interface) power management

ACPI is defined as a platform interface to the hardware detection, monitoring power management configuration. Determining the multiprocessor specification and Plug and Play devices. Besides power management aims to conserve power by stopping the power supply when not in use. Stages are controlled by the embedded operating system or known as Bios firmware file.
This firmware is executed with SPI Flash (Flash memory) electronic storage media that can be erased and reprogrammed electrically. (EEPROM electrically erasable programmable read-only memory). Firmawe this only works when run on the same circuit that has been in the program with Embedded controller and PCH were recorded.
This firmware is used to execute commands Basic input output system by sending a signal switches on the command input (trigger) S5_ON at SIO or embedded controller then forwards the order to the PCH (south bridge) switching system that activates the power supply to the Processor , Memory, Graphic Chip and others.




Power management hardware trigger events called system control interrupt (SCI), or simply setting the stage language that is tailored to the trigger signal power distribution stages.
The following outlines the stages of Power state governed by ACPI

1. S0: Trigger / gate driver signal or ordered by ACPI ready to pass power used by the device.

2. S3: Suspend State Signal. Suspension of the power distribution awaiting confirmation of Embedded controller to be enabled.

3. S5: State soft-off signal. All activities will cease, In addition to managing the transition between phases of the distribution of power, ACPI also manage the power supply of the individual devices to a fine level. For example, if two or more devices sharing the same power supply, the information can be encoded in the ACPI tables so that the power supply is only active if one or both of the devices are being used.

ROM (FIRMWARE STORAGE MEDIA)
EC Bios requires a main power supply for 3.3V ( VCC) pin 8 on the IC , we see that in the series. Pin 7 and pin 3 is also connected to VCC,Beside power and ground others Pin connected to the EC (embedded controller) as a two-way interface to process binary data and run circuit power management.