Abstract: Leakage current is eliminated in a memory array during a low power mode of a processing system having a processor that interfaces with the memory array. Because two power planes are created, the processor may continue executing instructions using a system memory while bypassing the memory array when the array is powered down. A switch selectively removes electrical connectivity to a supply voltage terminal in response to either processor-initiated control resulting from execution of an instruction or from a source originating in the system somewhere else than the processor. Upon restoration of power to the memory array, data may or may not need to be marked as unusable depending upon which of the two power planes supporting arrays to the memory array are located. Predetermined criteria may be used to control the timing of the restoration of power. Multiple arrays may be implemented to independently reduce leakage current.

Abstract: A method and system for improving memory access in Accelerated Graphics Port systems. The method and system associate a transaction id with individual data transactions within a number of Accelerated Graphics Port (AGP) pipelined data transactions, and identify the individual data transactions within the number of AGP pipelined data transactions via the transaction id. In one instance, the association of a transaction id with individual data transactions includes but is not limited to associating a transaction id with each individual memory read request within a number of AGP pipelined memory read requests and associating an identical transaction id with each individual data unit, within a number of pipelined data units, corresponding to each individual memory read request within the number of AGP pipelined memory requests.

Abstract: A method and system which will increase the ability of memory controllers to intelligently schedule accesses to system memory. The method and system provide a memory controller and a requested memory operation buffer structured so that at least one source attribute of a requested memory operation can be identified. In one instance, the requested memory operation buffer has queues, associated with data buses, which can be utilized to identify source attributes of requested memory operations. Examples of such queues are an Accelerated Graphics Port Interconnect queue associated with an Accelerated Graphics Port interconnect, a system bus queue associated with a system bus, and a Peripheral Component Interconnect bus queue associated with a Peripheral Component Interconnect bus where the queues can be utilized by a memory controller to identify the specific bus from which a requested memory operation originated.

Abstract: A method and system which will provide data processing systems having memory controllers with the ability to intelligently schedule accesses to system memory. The method and system provide a memory controller having a page-state sensitive memory arbiter. The method and system further include one or more memory state tracking units operably coupled to the page-state sensitive memory arbiter, and the one or more memory state tracking units operably coupled to a system memory. The one or more memory state tracking units operably coupled to a system memory further include the one or more memory state tracking units operably coupled to one or more system memory devices. The method and system track system memory status, monitor pending memory access requests, and schedule one or more pending memory access requests for execution dependent upon the system memory status and the pending memory access requests.

Abstract: An electronic system (100) includes a first integrated circuit (IC) (112) having a card system management interrupt (SMI) output pin (CRDSMI#) and interrupt pins (IRQ3-5), and a logic circuit (1620, 1630) having an output connected to the card SMI pin. This logic circuit further has inputs connected to a first and second set of registers and logic for first and second cards (CARD A,B) respectively. Each of the first and second sets of registers and logic include a first register (CSC REG) having bits set by at least a card event (CDCHG) and a battery condition event (BWARN) respectively. A logic gate (2672) responds to combine the bits from the first register. A second register (INT AND GEN CTRL REG) has a bit (SMIEN) for steering the output of the logic gate (2672) for ordinary interrupt or for system management interrupt purposes depending on the state of the bit (SMIEN).

Abstract: A method and system providing a memory controller having a destination-sensitive memory request reordering device. The destination-sensitive memory request reordering device includes a centralized state machine operably connected to one or more memory devices and one or more reorder and bank select engines. The centralized state machine is structured such that control information can be received from at least one of the one or more reorder and bank select engines over the one or more control lines. The centralized state machine is structured such that memory status information can be received from at least one of the one or more reorder and bank select engines over the one or more memory status lines, or such that memory status information can be determined by tracking past memory related activity. Additionally, the centralized state machine is structured to accept memory access requests having associated origin information.

Abstract: A method and system for substantially undetectable data processing. The method and system provide data processing systems with an ability to detect a specific event, and enter a background activity state in response to the specific event detected. The specific event detected can be some type of background activity state initiation event, such as a wake event or a time-out event. The entry of a background state in response to the specific event detected can be the initiation of a background routine appropriate to the specific event, such as the initiation of a routine capable of controlling system temperature by passive means.

Abstract: A method and system for improving data transmission in data processing systems, especially in the context of data processing systems utilizing the Accelerated Graphics Port (AGP) interface standard. The method and system provide an AGP-enabled device wherein is contained a command queue. The AGP-enabled device is connected to and communicates with an AGP-enabled bridge through and over a data bus. The AGP-enabled bridge has an AGP-enabled device mimicking unit. The AGP-enabled bridge also has an overflow protection unit. In one instance, the AGP-enabled device is an AGP-enabled graphics controller, the command queue is a graphics controller command queue, the AGP-enabled bridge is an AGP-enabled Northbridge, the data bus is an AGP interconnect, and the overflow protection unit is a mimicking buffer overflow detector and routing unit.

Abstract: It has been discovered that a method and system can be produced which will, among other things, provide data processing systems having memory controllers with the ability to look ahead and intelligently schedule accesses to system memory. A method and system which improve data processing system memory access. The method and system provide a first-stage origin-sensitive memory access request reordering device, and a second-stage destination-sensitive memory access request reordering device operably coupled to said first-stage origin-sensitive memory access request reordering device. The first-stage origin-sensitive memory access request reordering device receives memory access requests having associated origin information, and reorders the memory access requests based upon the associated origin information.

Abstract: A method and system for generating and utilizing speculative memory accesses in data processing systems. The method and system provide a memory controller having at least one origin-sensitive speculative memory access request generator. The origin-sensitive speculative memory access request generator is associated with one or more origins of memory access requests. In some embodiments, the origins are buses over which the one or more memory access request travel; in other embodiments the origins are sources of the one or more memory access requests. The origin-sensitive speculative memory access request generator monitors reorder buffers associated with the one or more origins, and in response to space in the reorder buffers generates speculative memory access requests of a type likely to be received by the reorder buffers in the future.

Abstract: A method and system which improve data processing system memory access. The method and system provide a memory controller having an origin-sensitive memory request reordering device. The origin-sensitive memory request reordering device includes one or more reorder and bank select engines, with at least one of such reorder and bank select engines associated with at least one origin of one or more memory access requests. In one embodiment, the origin of the memory access request is a bus (bus over which one or more memory access requests travel); in another embodiment the origin is a source. The reorder buffers are structured such that the reorder buffers can receive origin information related to specific memory access requests, where such information can include the identity of a source of a specific request, and various attributes of the specific request, such as the priority of the source associated with the request, an ordinal number of the request, the nature of the request, etc.

Abstract: An electronic system (100) includes a first integrated circuit (IC) (112) having a card system management interrupt (SMI) output pin (CRDSMI#) and interrupt pins (IRQ3-5), and a logic circuit (1620, 1630) having an output connected to the card SMI pin. This logic circuit further has inputs connected to a first and second set of registers and logic for first and second cards (CARD A,B) respectively. Each of the first and second sets of registers and logic include a first register (CSC REG) having bits set by at least a card event (CDCHG) and a battery condition event (BWARN) respectively. A logic gate (2672) responds to combine the bits from the first register. A second register (INT AND GEN CTRL REG) has a bit (SMIEN) for steering the output of the logic gate (2672) for ordinary interrupt or for system management interrupt purposes depending on the state of the bit (SMIEN).

Abstract: A computer system including an arrangement for programmably assigning interrupts to a larger set of interrupt channels. The computer system includes a microprocessing unit ("MPU" 102), a peripheral processing unit ("PPU" 110) that communicates with the MPU and a peripheral control unit ("PCU" 112) capable of communicating with the PPU and with at least one associated peripheral device. The PCU has associated therewith a first number, m, of interrupts for signalling to the MPU. The MPU has a second number, n, of interrupt channels over which interrupts are communicable to said MPU. A first register (IN1616) is provided in the PCU for storing a routing value representing the assignment of the m interrupts of the PCU to a selected subset of m channels of the n interrupt channels. A second register (IN1222) is provided in the PPU for storing the routing value. A number, m, connections are provided between the PCU and the PPU for transmitting the m interrupts from the PCU to the PPU.

Abstract: A programmable interrupt controller is provided for use in computer systems including one or more CPUs. The programmable interrupt controller includes an interrupt request interface, a storage device, and at least one processor interface having an interrupt nesting buffer. An interrupt request identification code is assigned to each interrupt request and stored in the nesting buffer. The interrupt request identification codes used to reference the interrupt requests are stored in order of their priority. Each nesting buffer need have only a number of entries equal to the number of priority levels.

Abstract: A programmable interrupt controller for use in computer systems including one or more CPUs is provided. The programmable interrupt controller includes an interrupt request interface, a central interrupt controller, random access memory, and at least one processor interface. The central interrupt controller systematically selects interrupt requests from the interrupt request interface. Information associated with each interrupt request is stored in the random access memory. The central interrupt controller access the information in the random access memory and uses the information and the state of the currently selected interrupt request to determine a next state for the currently selected interrupt request. The information is passed on to the processor interface to determine when and if the interrupt request should issue to one of the CPUs.

Abstract: A programmable interrupt controller for use in a multiprocessing environment that can support a serial bus to send interrupt information to the processors. The interrupt serial bus has a data line to drive all the interrupt information to all the processors and a clock line to synchronize edges for the data stream. A third line, normally tri-stated, may be used to provide a parity error indication for the serial bus. The serial data includes a processor identification, a pin identification and state information. As the programmable interrupt controller sends the interrupt data on the serial bus, all the processors clock the data and check parity. If a processor finds a parity error, it drives the parity error indication low so that the information may be transmitted again. No processor will execute the command contained in the serial message before the time has elapsed for any of the processors to report a parity error.

Abstract: A programmable interrupt controller is provided for use in computer systems including one or more CPUs. The programmable interrupt controller includes an interrupt request interface, a storage device, and at least one processor interface having an interrupt nesting buffer. An unique interrupt identification code is assigned to each interrupt request and used to reference information in the storage device associated with each interrupt request. The interrupt request interface uses the unique interrupt identification code to access the information for each interrupt request and determine if the interrupt request should proceed to one of the processor interfaces. The processor interface uses the unique interrupt identification code to access the information in order to determine if and when the interrupt request should issue to one of the CPUs.

Abstract: A programmable interrupt controller for use in computer systems including one or more CPUs is provided. The programmable interrupt controller includes an interrupt request interface, a validity checker, and at least one processor interface. The validity checker monitors the state of each interrupt request as it is processed through the interrupt controller. The interrupt request is canceled if the interrupt request becomes invalid. Alternatively, the programmable interrupt controller issues a spurious interrupt vector if the interrupt request becomes invalid after a CPU has responded.

Abstract: A processing system comprising at least one processing unit, a plurality of I/O devices, and a central interrupt control unit intercoupling the processing unit and the plurality of I/O devices. The central interrupt control unit is configured to receive interrupt signals from the I/O devices and is configured to distribute said interrupt signals to the processing unit. The central interrupt control unit is further configured to provide a signal simulative of an interrupt signal to simplify the testing process.

Abstract: A peripheral controller device (14) controlling at least a first peripheral device (16) attached thereto, the controller device including a programmable and selectable buffer memory for utilization with a first type and a second type of write instruction for writing data to first type (24) and a second type (26), respectively, of memory in the peripheral device (16). The peripheral controller device includes an n deep buffer memory (36), where n is an integer greater than one, for buffering the write instructions. A user may programmably indicate whether only the first type of write instruction is to be buffered or both types of instructions are to be buffered. Responsive to such programming, write instructions are examined to determine if they are of the first type or the second type. Depending on the programming, write instructions of the second type are routed to the buffer or are routed by bypassing the buffer memory.