Abstract: A clock generator circuit may include a multiplex circuit and a phase-locked loop circuit. The multiplex circuit may generate a reference clock signal for the phase-locked loop circuit by selecting one of different clock signals. In response to a switch of the reference clock signal from one clock signal to another, the phase-locked loop circuit may disable phase-locking and enter into a frequency acquisition mode during which the frequency of the phase-locked loop circuit's output clock signal is adjusted based on the frequency of the newly selected reference clock signal. After a period of time has elapsed, the phase-locked loop circuit returns to phase-locking operation.

Abstract: A portable computer can be “hot” docked to one or more expansion devices, such as a drive wedge and a port replicator. As such, the expansion devices can be connected to and disconnected from the portable computer while portable computer is powered on and fully operational. The portable computer includes control logic that detects when an expansion device is connected to or disconnected from the portable computer and asserts an SMI or equivalent interrupt signal to the computer's CPU to initiate a sequence of events by which the computer determines whether an expansion device has been connected or disconnected. If the CPU determines that the expansion device has been connected to the computer, the CPU appropriately reconfigures itself to communicate with the expansion device. If the expansion device is disconnected, the CPU also appropriately reconfigures itself to preclude communications with the disconnected device.

Abstract: A portable computer can be “hot” docked to one or more expansion devices, such as a drive wedge and a port replicator. As such, the expansion devices can be connected to and disconnected from the portable computer while portable computer is powered on and fully operational. The portable computer includes control logic that detects when an expansion device is connected to or disconnected from the portable computer and asserts an SMI or equivalent interrupt signal to the computer's CPU to initiate a sequence of events by which the computer determines whether an expansion device has been connected or disconnected. If the CPU determines that the expansion device has been connected to the computer, the CPU appropriately reconfigures itself to communicate with the expansion device. If the expansion device is disconnected, the CPU also appropriately reconfigures itself to preclude communications with the disconnected device.

Abstract: A portable computer can be “hot” docked to one or more expansion devices, such as a drive wedge and a port replicator. As such, the expansion devices can be connected to and disconnected from the portable computer while portable computer is powered on and fully operational. The portable computer includes control logic that detects when an expansion device is connected to or disconnected from the portable computer and asserts an SMI or equivalent interrupt signal to the computer's CPU to initiate a sequence of events by which the computer determines whether an expansion device has been connected or disconnected. If the CPU determines that the expansion device has been connected to the computer, the CPU appropriately reconfigures itself to communicate with the expansion device. If the expansion device is disconnected, the CPU also appropriately reconfigures itself to preclude communications with the disconnected device.

Abstract: A computer system having a core logic chipset that interconnects a processor(s), a system memory and peripheral device agents. The core logic chipset has a programmable memory access arbiter that may be programmed to optimize accesses by the computer system processor(s) and agents to the system memory for best computer system performance. The memory access arbiter may be programmed specifically for each system agent. An access count register may be incorporated into the core logic chipset wherein each system agent may be represented by a portion of the access count register. The values programmed into the portions of the access count register determine how many memory accesses the associated agent may take before another agent is granted a memory access, and how many cachelines may be transferred during a memory access.

Abstract: A computer is provided having a bus interface unit which is coupled between a peripheral bus and a dedicated graphics bus. The graphics bus can be linked to the bus interface unit by an AGP, while the peripheral bus can be linked to the bus interface unit by a PCI. Arbitration for the AGP bus can determine when mastership is granted to an AGP master (i.e., graphics accelerator/controller). Until mastership is granted, the AGP target is powered down to a low power state where power consumption within the bus interface unit is minimal. It is not until the AGP master achieves mastership that the graphics target (core logic and memory controller) within the bus interface unit is placed in an operational (fully powered) state. The computer therefore employs a bus interface unit which can be dynamically switched from a high power state to a low power state and vice versa, depending upon accesses to the graphics target.

Abstract: A computer system having a core logic chipset that functions as a bridge between an Accelerated Graphics Port ("AGP") bus device such as a graphics controller, and a host processor and computer system memory wherein a Graphics Address Remapping Table ("GART table") is used by the core logic chipset to remap virtual memory addresses used by the AGP graphics controller into physical memory addresses that reside in the computer system memory. The GART table enables the AGP graphics controller to work in contiguous virtual memory address space, but actually use non-contiguous blocks or pages of physical system memory to store textures, command lists and the like. Contiguous virtual memory address space must be allocated for the AGP device within the addressable memory space of the computer system, typically 4 gigabytes using 32 bit addressing.

Abstract: A computer system having a core logic chipset that functions as a bridge between an Accelerated Graphics Port ("AGP") bus device such as a graphics controller, and a host processor and computer system memory wherein a Graphics Address Remapping Table ("GART table") is used by the core logic chipset to remap virtual memory addresses used by the AGP graphics controller into physical memory addresses that reside in the computer system memory. The GART table enables the AGP graphics controller to work in contiguous virtual memory address space, but actually use non-contiguous blocks or pages of physical system memory to store textures, command lists and the like. The GART table is made up of a plurality of entries, each entry comprising an address pointer to a base address of a memory page, and feature flags that may be used to customize the associated memory page.

Abstract: A computer system having a core logic chipset that functions as a bridge between an Accelerated Graphics Port ("AGP") bus device such as a graphics controller, and a host processor and computer system memory wherein a Graphics Address Remapping Table ("GART table") is used by the core logic chipset to remap virtual memory addresses used by the AGP graphics controller into physical memory addresses that reside in the computer system memory. The GART table enables the AGP graphics controller to work in contiguous virtual memory address space, but actually use non-contiguous blocks or pages of physical system memory to store textures, command lists and the like. The GART table is made up of a plurality of entries, each entry comprising an address pointer to a base address of a page of graphics data in memory, and feature flags that may be used to customize the associated page. One of the feature flags is used as a Present Bit for a corresponding memory page.

Abstract: A computer system having a core logic chipset that functions as a bridge between an Accelerated Graphics Port ("AGP") bus device such as an AGP graphics controller, and a host processor and computer system memory wherein AGP transaction read requests are merged from the AGP graphics controller and retired when these requests are within a cacheline of the memory being accessed. The core logic chipset will request a memory cacheline read as it begins processing a current AGP transaction read request. Once the memory read access is initiated, the transaction read request will be popped off an AGP request queue in order to evaluate the next in order transaction request. If the next request can be partially or completely retired by the memory read access previously started, then the memory access that would have been normally required may be skipped and the data from the previous memory read access is used instead.

Abstract: A computer system having a core logic chipset that functions as a bridge between an Accelerated Graphics Port ("AGP") bus device such as a graphics controller, and a host processor and computer system memory wherein a Graphics Address Remapping Table ("GART table") is used by the core logic chipset to remap virtual memory addresses used by the AGP graphics controller into physical memory addresses that reside in the computer system memory The GART table enables the AGP graphics controller to work in contiguous virtual memory address space, but actually use non-contiguous blocks or pages of physical system memory to store textures, command lists and the like. The GART table is made up of a plurality of entries, each entry comprising an address pointer to a base address of a page of graphics data in memory. The core logic chipset may cache a subset of the most recently used GART table entries to increase AGP performance when performing the address translation.

Abstract: A computer system having a core logic chipset that functions as a bridge between an Accelerated Graphics Port ("AGP") bus device such as a graphics controller, and a host processor and computer system memory wherein a Graphics Address Remapping Table ("GART table") is used by the core logic chipset to remap virtual memory addresses used by the AGP graphics controller into physical memory addresses that reside in the computer system memory. The GART table enables the AGP graphics controller to work in contiguous virtual memory address space, but actually use non-contiguous blocks or pages of physical system memory to store textures, command lists and the like. A plurality of AGP memory-mapped status and control registers are stored in the computer system memory, and are used for status and control of AGP functions in the computer system.

Abstract: A computer system having a core logic chipset that functions as a bridge between an Accelerated Graphics Port ("AGP") bus device such as a graphics controller, and a host processor and computer system memory wherein a Graphics Address Remapping Table ("GART table") is used by the core logic chipset to remap virtual memory addresses used by the AGP graphics controller into physical memory addresses that reside in the computer system memory. The GART table enables the AGP graphics controller to work in contiguous virtual memory address space, but actually use non-contiguous blocks or pages of physical system memory to store textures, command lists and the like. The GART table is made up of a plurality of entries, each entry comprising an address pointer to a base address of a page of graphics data in the computer system physical memory, and feature flags that may be used to customize the associated page of graphics data.

Abstract: A computer system having a core logic chipset that functions as a bridge between an Accelerated Graphics Port ("AGP") bus device such as a graphics controller, and a host processor and computer system memory wherein a Graphics Address Remapping Table ("GART table") is used by the core logic chipset to remap virtual memory addresses used by the AGP graphics controller into physical memory addresses that reside in the computer system memory. The GART table enables the AGP graphics controller to work in contiguous virtual memory address space, but actually use non-contiguous blocks or pages of physical system memory to store textures, command lists and the like. Contiguous virtual memory address space must be allocated for the AGP device within the addressable memory space of the computer system, typically 4 gigabytes using 32 bit addressing.

Abstract: A computer system having a core logic chipset that functions as a bridge between an Accelerated Graphics Port ("AGP") bus device such as a graphics controller, and a host processor and computer system memory wherein a Graphics Address Remapping Table ("GART table") is used by the core logic chipset to remap virtual memory addresses used by the AGP graphics controller into physical memory addresses that reside in the computer system memory. The GART table enables the AGP graphics controller to work in contiguous virtual memory address space, but actually use non-contiguous blocks or pages of physical system memory to store textures, command lists and the like. The GART table is made up of a plurality of entries, each entry comprising an address pointer to a base address of a page of graphics data in memory, and feature flags that may be used to customize the associated page.

Abstract: A computer system having an expansion base for docking a portable portion of the computer system includes a bridge circuit for adaptively decoding addresses on a bus based on the docking status. Both the expansion base and the portable portion include the bridge circuit for passing cycles from a peripheral component interconnect (PCI) bus to an industry standard architecture (ISA) bus. The bridge includes internal devices and configuration registers for controlling the decoding. Bus cycles intended for internal devices and external devices connected to each respective ISA bus of the bridge circuits are positively decoded. Cycles not positively decoded and claimed are subtractively decoded by one of the bridge circuits depending on the docking status.

Abstract: A computer system having an expansion base for docking a portable portion of the computer system includes a bridge circuit for adaptively decoding addresses on a bus based on the docking status. Both the expansion base and the portable portion include the bridge circuit for passing cycles from a peripheral component interconnect (PCI) bus to an industry standard architecture (ISA) bus. The bridge includes internal devices and configuration registers for controlling the decoding. Bus cycles intended for internal devices and external devices connected to each respective ISA bus of the bridge circuits are positively decoded. Cycles not positively decoded and claimed are subtractively decoded by one of the bridge circuits depending on the docking status.

Abstract: A dual-master data storage interface is disclosed which flexibly configures and connects data storage drives in the portable computer to optimize performance when the portable computer is operating in a stand-alone mode and to optimize accessibility to additional data storage drives when the portable computer is docked with an expansion unit. When the portable computer operates as a stand-alone unit (i.e., not docked to the expansion unit), each drive on the portable is configured to operate as a master drive to optimize performance. When the portable computer docks with the expansion unit, the first channel on the portable computer is connected via switches to both drives of the portable computer, while the second channel on the portable computer is disconnected. Further, the first data storage drive is configured as a master and the second data storage drive is configured as a slave drive on the portable computer side.

Abstract: A method and system for improving bus-to-bus data transfers in a multi-bus computer system is provided. The system includes a system bus having a slave device attached thereto, a peripheral bus having a master device attached thereto, and a host bridge connecting the two buses. The system bus permits burst read transfers of data stored in the slave device, wherein a single address phase is followed by several data phases, but only if the first address corresponds to a prescribed system bus boundary. The peripheral bus is not subject to address boundary limitations, instead permitting burst read transfers beginning at any address. The host bridge includes logic for decoding a first address asserted by the master device to determine if it corresponds to a system bus boundary.

Abstract: Hardware logic within a host bridge that connects a system bus to a peripheral bus using PCI bus architecture or a peripheral bus that uses a bus architecture similar to PCI. The hardware optimizes the speed at which data transfers are accomplished between the buses while translating the data transfers between the different architectures of the two buses.