Abstract: A computer system having a responsive low-power mode and a full-power mode of operation. The computer system includes a power consumption controller, a processor and a communication device. The power consumption controller generates an interrupt signal in response to a low power event or a fully operational event. The power consumption controller also generates a clock control signal. The clock control signal is deasserted during the full-power mode of operation and alternatively asserted for a first duration and deasserted for a second duration during the low-power mode of operation. In response to an asserted clock control signal, the processor suppresses the internal clock signal to at least one functional block within the processor and in response to a deasserted clock control signal, the processor transmits the internal clock signal to at least one functional block within the processor.

Abstract: A device and method for transferring data, address and status information concerning a former I/O bus cycle before a system management interrupt is initiated. A plurality of system management shadow registers samples information from a system bus. Such information is obtained by a register accessing the plurality of system management shadow registers through a common shadow port.

Abstract: A computer system has both positive decode agents and subtractive decode agents that are targets of bus transactions, as well as an agent that does not perform a positive decode of a bus transaction, yet does claim bus transactions on behalf of agents to whom a bus transaction is directed.

Abstract: An apparatus and method for controlling the stopping of the clock signal utilized by the processing unit of a computer system comprises the use of a novel external pin which can be enabled to initiate a sequence of events that results in the halting of the internal clock signal. The invention includes a microcode engine that responds to the assertion of the external pin by executing a sequence of steps which stops the current instruction on an instruction boundary. A logic circuit then generates a signal that masks the clock signal produced by the system's phase-locked loop. An interrupt mechanism is also utilized to prioritize the occurrence of the external signal among other system interrupts. The interrupt mechanism insures that the processor never has its clock stopped in the middle of a bus cycle.

Abstract: An apparatus and method for controlling the stopping of the clock signal utilized by the processing unit of a computer system comprises the use of a novel external pin which can be enabled to initiate a sequence of events that results in the halting of the internal clock signal. The invention includes a microcode engine that responds to the assertion of the external pin by executing a sequence of steps which stops the current instruction on an instruction boundary. A logic circuit then generates a signal that masks the clock signal produced by the system's phase-locked loop. An interrupt mechanism is also utilized to prioritize the occurrence of the external signal among other system interrupts. The interrupt mechanism insures that the processor never has its clock stopped in the middle of a bus cycle.

Abstract: An apparatus and method for controlling the stopping of the clock signal utilized by the processing unit of a computer system comprises the use of a novel external pin which can be enabled to initiate a sequence of events that results in the halting of the internal clock signal. The invention includes a microcode engine that responds to the assertion of the external pin by executing a sequence of steps which stops the current instruction on an instruction boundary. A logic circuit then generates a signal that masks the clock signal produced by the system's phase-locked loop. An interrupt mechanism is also utilized to prioritize the occurrence of the external signal among other system interrupts. The interrupt mechanism insures that the processor never has its clock stopped in the middle of a bus cycle.

Abstract: A power suspend mode activates a slow DRAM refresh in a computer system with a limited source of power. The power suspend mode reduces the power consumed by the computer system while preserving the contents of memory. The cyclic refresh of DRAM using a slow refresh clock substantially reduces the power consumed while the computer is suspended. This technique is particularly useful for battery powered portable computer systems. When an external or internal condition causes the computer system to transition to a power down mode, an IO subsystem notifies the CPU which sets control bits in the IO subsystem and a video subsystem. The IO subsystem then begins to generate a slow DRAM refresh pulse. Once the CPU and video subsystem sense the power suspend mode activation, the system memory and video memory are refreshed using the slow refresh clock. The power consumed during the refresh process is thereby greatly reduced.

Abstract: A method and mechanism for suspending and resuming a keyboard controller. The present invention includes a method and mechanism for saving the state of an input device, such as a keyboard and/or mouse, such that the power to those devices may be removed. The keyboard controller of the present invention is capable of performing a password security function. The present invention allows the keyboard controller to be suspended and resumed without jeopardizing the password security function.