介绍APM BIOS接口（PPT53）.pptVIP

Introduce the APM BIOS Interface Agenda 1.APM Introduction 2.APM Model 3.APM Software Layer 4.APM Software Interface 5.Firmware Error Codes 6.Summaries 7.QA 1.APM Introduction 1.1 APM Overview 1.2 APM System 1.3 Terms 1.1 APM Overview What is APM? APM( advanced power management) is defined by Intel and Microsoft Corp in 1992. The latest version is 1.2. Function of APM: Control the device power sate through BIOS . APM VS ACPI: In ACPI environment OS control all device’s power state and the BIOS provide system information only. 1.2 APM System 1.2 APM System APM BIOS is the software interface to the motherboard and its power managed devices . APM driver module connects to the APM BIOS and communicate with the APM-aware application. APM-aware Device Driver modules provides the software interface for add-in devices. APM-aware Applications interface with the APM driver to monitor and control power management 1.3 Terms Add-in Device is not on the motherboard. APM Connection is a protocol and mechanism by which an APM Driver and an APM BIOS intercommunicate. CPU CORE includes the CPU clock, cache, system bus, and system timers. Resume timer is a system timer used to wake up the system from a low power state at a specified time. System Idle is a inactive state . 2. APM Model 2.1 System Power State 2.2 Device Control 2.3 CPU Control 2.4 System Power State Transition 2.1 System Power States 2.1.1 Full On State 2.1.2 APM Enable State 2.1.3 APM Standby 2.1.4 APM Suspend 2.1.5 Off State 2.1.1 Full On State The Full On State is the default mode. System is on working. System is not power managed. All device are on. 2.1.2 APM Enable State In the APM Enable State the system is doing work but some unused devices may not be powered. The CPU clock is slowed or stopped and devices are power managed as needed. 2.1.3 APM Standby The system enters the APM Standby State after a short period inactivity. The system is in a low power state with some power savings.