公开(公告)号：BR9505208A

公开(公告)日：1997-09-16

申请号：BR9505208

申请日：1995-11-17

Applicant: IBM

Inventor： KULIK AMY ,  WALL WILLIAM ALAN ,  CRONIN DANIEL R

IPC: G06F11/30 ,  G06F11/10 ,  G06F13/36 ,  G06F13/40

Abstract: A peripheral controller interconnect/industry standard architecture (PCI/ISA)bridge is coupled between the PCI and ISA buses in a computer system. A PCI master in the system asserts address and address parity information on the PCI bus to initiate a master-slave transaction over the PCI bus. The bridge includes logic for comparing the address and the address parity information and generating an address parity error signal when there is an address parity error. The bridge also includes a PCI slave that receives the address parity error signal and generates a target-abort signal in response if the PCI slave has already claimed the address by asserting a device select signal. The bridge also includes logic that prevents the target-abort signal from propagating to the PCI bus whenever this logic receives both the address parity error signal and the device select signal. This allows the master to perform a master-abort and prevents the PCI slave on the bridge from performing a target-abort when there is an address parity error.

公开(公告)号：BR9505207A

公开(公告)日：1997-09-16

申请号：BR9505207

申请日：1995-11-17

Applicant: IBM

Inventor： KATZ SAGI ,  WALL WILLIAM ALAN ,  KULIK AMY ,  CRONIN DANIEL R

IPC: G06F13/36 ,  G06F13/40 ,  G06F13/42

Abstract: A computer system having an ISA bus and a PCI bus is provided with a PCI to ISA bridge having certain imbedded functions performed by PCI slaves on the bridge. In order to implement the bridge in slow CMOS technology, the PCI control signals are latched on the bridge. Since the PCI slaves on the bridge cannot respond with control signals on the PCI bus fast enough to satisfy the PCI bus protocol due to this latching, a logic device is provided on the bridge. The logic device monitors the unlatched master-slave control signals carried on the PCI bus, and in appropriate situations, drives the control signals on the PCI bus (within the time specified by the PCI bus protocol) that the PCI slaves would normally drive but are unable to within the time necessary to meet the PCI bus protocol.

公开(公告)号：BR9505209A

公开(公告)日：1997-09-16

申请号：BR9505209

申请日：1995-11-17

Applicant: IBM

Inventor： BLAND PATRICK MAURICE ,  CRONIN DANIEL R ,  HOFMANN RICHARD G ,  MOELLER DENNIS ,  VENARCHICK LANCE M

IPC: G06F12/06 ,  G06F13/28 ,  G06F13/36 ,  G06F13/40

Abstract: A computer system that has two buses (30, 32) with different memory addressing capacities and a first bus master (36) that generates M-bit addresses is provided with a bridge (34) between the two buses. In order to generate N-bit addresses for use on the second bus (30), a direct memory access (DMA) controller (50) on the bridge produces P bits, where P + M = N. The P bits are concentrated with the M bits to form an N-bit address used on the second bus (30) to address memory (40). The addition of P bits reallocates the memory segment addressable by the M-bits to any location within the memory map addressable by an N-bit address.