Compaq Computer Corporation, Inc.

Shaun V Wandler

Todd J Deschepper

Jeffrey C Stevens

Jeff W Wolford

Russ Wunderlich

Robert L Woods

Jeffrey T Wilson

Danny Higby

Maria L Melo

A computer system includes a CPU and a memory device coupled by a North bridge logic unit to an expansion bus, such as a PCI bus. A South bridge logic connects to the expansion bus and couples various secondary busses and peripheral devices to the expansion bus. The South bridge logic includes internal control devices or master devices that are designed to run master cycles on the expansion bus. The master devices couple to the expansion bus through a common expansion master interface, which executes master cycles on the expansion bus on behalf of the master devices. The South bridge also includes an internal modular master expansion bus coupling the internal master devices to the common master interface. The internal modular master expansion bus permits the master devices to run master cycles to any expansion bus by understanding a standardized group of signals represented by the internal modular master expansion (IMAX) bus. The master interface then is responsible for understanding the protocol of the expansion bus and converting the IMAX master bus signals to signals compatible with the expansion bus. In addition, a dedicated target IMAX bus may also be provided for coupling internal targets within the South bridge to masters on the expansion bus through a common expansion target interface.

Computer system with bridge logic that includes an internal modular expansion bus and a common master interface for internal master devices

A computer system includes a CPU and a memory device coupled by a North bridge logic unit to an expansion bus, such as a PCI bus. A South bridge logic connects to the expansion bus and couples various secondary busses and peripheral devices to the expansion bus. The South bridge logic includes internal control devices that are targets for masters on the expansion bus. The target devices couple to the expansion bus through a common expansion target interface, which monitors and translates master cycles on the expansion bus on behalf of the target devices. The South bridge also includes an internal modular target expansion bus coupling the internal target devices to the common target interface. The internal modular target expansion bus permits the target devices to receive master cycles from any expansion bus by understanding a standardized group of signals represented by the internal modular target expansion (IMAX) bus. The target interface then is responsible for understanding the protocol of the expansion bus and converting the expansion bus signals to IMAX target bus signals. The IMAX target bus includes both an inbound bus and an outbound data bus for driving out data requested as part of a read cycle to an internal target device.

Computer system with bridge logic that includes an internal modular

A computer system includes a CPU and a memory device coupled through a North bridge logic device. The computer also includes a South bridge logic device coupled to the North bridge by a primary bus. The South bridge waits as long as possible before asserting a flush request (FLUSHREQ) control signal to the North bridge. The South bridge asserts the FLUSHREQ signal to the North bridge after a peripheral device coupled to the South bridge requests access to the primary bus to run a cycle. The South bridge first flushes a write queue before asserting the FLUSHREQ signal to the North bridge. In response to the FLUSHREQ control signal, the North bridge flushes one or more of its own internal write queues in preparation for the upcoming peripheral device cycle. By flushing its own internal write queue before asserting FLUSHREQ to the North bridge, the South bridge reduces the amount of time that the CPU will be prevented from accessing the primary expansion bus while the peripheral device attempts to run a cycle on the primary bus. An alternative embodiment of the invention includes a pair of South bridges, one South bridge in a laptop computer and the other South bridge in an expansion base to which the laptop computer mates.

Computer system with bridge logic that reduces interference to CPU

Growing community of inventors

Tomball, TX, United States of America

Shaun V Wandler