Multifunction power switch and feedback led for suspend systems

Claim 1

A computer system capable of operating in any selected one of four states of power management, namely a normal operating state in which code is executed normally by said computer system, a standby state, an off state, and a suspend state, the system comprising: (a) a CPU capable of executing code; (b) a power management unit in circuit communication with said CPU for changing said computer system between each of said states and at least one other of said states in response to at least one of a plurality of preselected events; said power management unit having an internal failsafe timer in circuit communication with said CPU, said failsafe timer being set to expire after a first preselected time interval after said code executing on said CPU ceases executing properly, (c) a switch in circuit communication with said power management unit; (d) a peripheral device in circuit communication with said CPU and said power management unit and capable of operating in a selected one of a high electrical power usage state and a low electrical power usage state, said peripheral device changing between said high and low electrical power usage states in response to said power management unit; (e) a non-volatile storage device in circuit communication with said CPU, said non-volatile storage device requiring no electrical power to maintain data stored therein: (f) volatile system memory in circuit communication with said CPU and for storing memory data; (g) a power supply in circuit communication with said CPU and said power management unit and said peripheral device and comprising power selection circuitry for selectively providing system power from an external source to said computer system, said power supply being capable of operating in a selected one of a first power supply state and a second power supply state, said power supply changing between said first and second power supply states in response to said power management unit, and further characterized by having circuitry for providing auxiliary power to said power management unit; wherein said first power supply state is characterized by said power supply providing system power to said CPU, said non-volatile storage device, and said volatile system memory and auxiliary power to said power management unit from said external source; wherein said second power supply state is characterized by said power supply not providing system power to said CPU, said non-volatile storage device, and said volatile system memory from said external source and said power supply providing auxiliary power to said power management unit from said external source; (1) said normal operating state being characterized in that said power supply is in said first power supply state and said peripheral device is in said high electrical power usage state; (2) said standby state being characterized in that said power supply is in said first power supply state and said peripheral device is in said low electrical power usage state; (3) said suspend state being characterized in that said power supply is in said second power supply state and code which was executing on said CPU prior to entering said suspend state has been reversibly interrupted such that the execution of the code on said CPU may be resumed after said power supply changes to said first power supply state; (4) said off state being characterized in that said power supply is in said second power supply state and code which was executing on said CPU prior to entering said off state has been irreversibly interrupted; and (5) said power management unit being characterized in that while in said standby state or said suspend state or said on state, responsive to a closure event of said switch, said power management unit tests said failsafe timer for expiration and if said failsafe timer has expired, said power management unit immediately causes said computer system to change to said off state.