Smart battery power management in a computer system
First Claim
1. A bridge logic unit, comprising:
- a programmable interrupt controller receiving at least one interrupt request signal; and
a power management logic unit coupled to said programmable interrupt controller and capable of asserting a SLEEPREQ signal that causes a CPU clock to be turned off when SLEEPREQ is asserted;
said power management logic unit comprising a first programmable CPU stop clock register including modulation bits by which the SLEEPREQ signal is dynamically modulated so that the SLEEPREQ signal is asserted only for a programmed number of cycles of a clock signal and a second programmable CPU stop clock register including modulation bits by which the SLEEPREQ signal is dynamically modulated so that the SLEEPREQ signal is asserted only for a programmed number of cycles of said clock signal when said SLEEPREQ signal is not being modulated by said first programmable CPU stop clock register, said programmed number of cycles defined by the value of said modulation bits of each of said stop clock registers.
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Accused Products
Abstract
A computer system includes bridge logic that couples peripheral devices to a CPU and main memory and includes power management logic and a programmable interrupt controller. The power management logic includes control logic, a stop clock register, an alternate stop clock register, and a wakeup event register. The operating system initiates a transition to a lower power mode of operation by issuing an IDLE call to the BIOS which responds by configuring a modulation value of 15 into the alternate stop clock register. With a modulation value of 15, the SLEEPREQ signal is continuously asserted disabling the CPU'"'"'s internal clock. When a subsequent wakeup event occur, an enable bit in the alternate stop clock register is cleared, disabling modulation and deasserting SLEEPREQ. In response to the wakeup event, the amount of SLEEPEQ modulation is changed. Preferably the modulation value is changed to 14 so that SLEEPREQ is asserted for 14 out of every 15 cycles of a 32 KHz clock. The wakeup event register is configured to disable the system timer from being again causing a wakeup event. If a subsequent wakeup event is then detected, either the enable bit in the alternate stop clock register is cleared to disable SLEEPREQ modulation or the modulation value is programmed to a value of 0. If the enable bit is cleared, SLEEPREQ modulation is determined by the modulation value in a secondary stop clock register.
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Citations
31 Claims
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1. A bridge logic unit, comprising:
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a programmable interrupt controller receiving at least one interrupt request signal; and a power management logic unit coupled to said programmable interrupt controller and capable of asserting a SLEEPREQ signal that causes a CPU clock to be turned off when SLEEPREQ is asserted; said power management logic unit comprising a first programmable CPU stop clock register including modulation bits by which the SLEEPREQ signal is dynamically modulated so that the SLEEPREQ signal is asserted only for a programmed number of cycles of a clock signal and a second programmable CPU stop clock register including modulation bits by which the SLEEPREQ signal is dynamically modulated so that the SLEEPREQ signal is asserted only for a programmed number of cycles of said clock signal when said SLEEPREQ signal is not being modulated by said first programmable CPU stop clock register, said programmed number of cycles defined by the value of said modulation bits of each of said stop clock registers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A computer system, comprising:
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a CPU including an internal CPU clock signal that can be enabled or disabled by a STOPCLK signal provided to said CPU; a main memory device; a primary expansion bus; a North bridge coupling together said CPU, said main memory device, and said primary expansion bus; and a South bridge coupling a secondary expansion bus to said primary expansion bus, said South bridge including; a programmable interrupt controller receiving at least one interrupt request signal defining a wakeup event that causes said CPU clock to be enabled; and a power management logic unit coupled to said programmable interrupt controller and capable of asserting a SLEEPREQ signal to said North bridge that responds by asserting said STOPCLK signal to said CPU to disable said CPU clock; said power management logic unit comprising a programmable alternate CPU stop clock register including bits by which the SLEEPREQ signal is dynamically modulated so that the SLEEPREQ signal is asserted only for a programmed number of cycles of a first clock signal, said programmed number of cycles defined by the value of said modulation bits. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method for controlling the power drain in a computer system, comprising:
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initiating a low power mode of operation by asserting a SLEEPREQ signal to cause a CPU clock to be disabled; detecting a first wakeup event; modulating said SLEEPREQ signal to cause said CPU clock to be disabled while said SLEEPREQ is asserted and enabled while said SLEEPREQ is deasserted; disabling a system timer event from being a wakeup event; and changing the amount of modulation of said SLEEPREQ signal when a second wakeup event is detected. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31)
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Specification