Abstract: In accordance with an embodiment of the present invention, a triggering event is initiated to place a processor in a low power state. The processor may or may not flush a cache upon entering the low power state depending on a power status signal. The power status signal may indicate the relative priority of power reduction associated with placing the processor in the low power state without first flushing the cache versus an increase in soft error rate in the cache associated with reducing the voltage in the low power state.

Abstract: A voltage regulator is described which uses external resistors to set a load line and offset. During initial operation and also during normal operation the load line and offset are reset by placing, for instance, the microprocessor in a high active state, low active state and in a sleep mode. By dynamically changing the load line and offset voltage, minimum current is drawn thus extending battery life.

Abstract: A voltage regulator is described which uses external resistors to set a load line and offset. During initial operation and also during normal operation the load line and offset are reset by placing, for instance, the microprocessor in a high active state, low active state and in a sleep mode.

Abstract: A method is disclosed including generating a digital control signal having a duty cycle which varies randomly or pseudo-randomly between a number of cycles, and is substantially fixed when averaged over the cycles. A target signal such as a digital clock signal may be passed selectively, in accordance with the control signal. A particular application of the method is power management in computers and other electronic systems that feature high performance processor and memory configurations that involve synchronous accesses of the memory by the processor.

Abstract: A method and apparatus which may be used for control of the rate of change of current consumption of an electronic component. The apparatus includes a processing circuit having coupled to receive a throttling signal that throttles operation of the electronic component. The apparatus also includes a power management circuit which detects a power consumption change of the processing circuit generates the throttling signal in response to the power consumption change event.

Abstract: In some embodiments, the invention includes a system having a normal operating mode and a suspend mode. The system includes event recognition circuitry to provide an event status signal. The system also includes clock generating circuitry with selective stretching capability to generate an internal clock signal and to receive the event status signal, and wherein when the event status signal has a first logic state, the clock generating circuitry stretches the internal clock signal by a number of phases per cycle of a bus clock signal wherein an alignment relationship between the internal clock signal and the bus clock signal is immediately deterministic in transitions between the suspend mode and the normal operating mode.

Abstract: A novel method and apparatus to cache System Management Mode (SMM) data with other data to improve performance and reduce latency of SMM handler routines. This method and apparatus allows SMM data and non-SMM data to be distinguished in the cache without requiring extra cache bits which can add to the cost of implementation. Since SMM data and non-SMM data can coexist in the cache, there is no need for time consuming cache flush cycles when switching between the two modes. Since SMM data can be cached, performance of SMM routines are improved. This method and apparatus defines the SMRAM address range to be a range of addresses representable by the tag, but not directly corresponding to installed main memory. When accesses are made to SMRAM addresses, they are redirected to an unused portion of main memory. Protection mechanisms may be implemented to limit access to these SMRAM addresses when not in SMM.

Abstract: A computer system that implements a direct memory access (DMA) request passing protocol. The computer system may comprise a Peripheral Component Interconnect (PCI) bus that includes an electrical interface as specified by a PCI Local Bus standard. The PCI bus is coupled to at least one DMA agent and a DMA controller. The DMA agent issues DMA requests to the DMA controller using the electrical interface of the PCI bus. According to one embodiment, a system I/O controller receives the DMA requests and passes them on to the DMA controller, which arbitrates the DMA requests and passes back a grant to the system I/O controller. The system I/O controller uses the electrical interface of the PCI bus to pass the grant to the DMA agent. The same DMA request passing protocol may be implemented in any bus having an electrical interface that specifies a unique request signal line for each bus agent of the bus.

Abstract: A computer system performs direct memory access (DMA) transfers according to a DMA transfer protocol. The computer system may comprise a Peripheral Component Interconnect (PCI) bus that includes an electrical interface as specified by a PCI Local Bus standard. A DMA agent, system memory, and a DMA controller are coupled to the bus. The DMA controller uses the electrical interface of the PCI bus to control a DMA transfer between system memory and the DMA agent. According to one embodiment, a system I/O controller is coupled between the DMA controller and the PCI bus. The system I/O controller passes DMA control information from the DMA controller to the DMA agent using the electrical interface of the PCI bus. The electrical interface of the PCI bus includes a plurality of address lines and a grant signal line coupled to the DMA agent, wherein the system that I/O controller transmits DMA control information to the DMA agent while asserting the grant signal line.

Abstract: A computer system that implements a direct memory access (DMA) request passing protocol. The computer system may comprise a Peripheral Component Interconnect (PCI) bus that includes an electrical interface as specified by a PCI Local Bus standard. The PCI bus is coupled to at least one DMA agent and a DMA controller. The DMA agent issues DMA requests to the DMA controller using the electrical interface of the PCI bus. According to one embodiment, a system I/O controller receives the DMA requests and passes them on to the DMA controller, which arbitrates the DMA requests and passes back a grant to the system I/O controller. The system I/O controller uses the electrical interface of the PCI bus to pass the grant to the DMA agent. The same DMA request passing protocol may be implemented in any bus having an electrical interface that specifies a unique request signal line for each bus agent of the bus.