Data transfer method between buses, bridge devices for interconn

Details Data transfer method between buses, bridge devices for interconn Data transfer method between buses, bridge devices for interconn

1998-01-28

2000-06-13

Sheikh, Ayaz R.

Electrical computers and digital data processing systems: input/

Intrasystem connection

Bus access regulation

710120, 710126, 710129, G06F 1338, G06F 1340

Patent

active

060761288

ABSTRACT:
The object of the present invention is to eliminate, in a data processing system having multiple buses, a combination of devices that can not be accessed via a PCI to PCI bridge. When an access request is issued to an S.sub.-- ISA device by an S.sub.-- PCI device, a PCI to PCI bridge determines whether or not a requested address is outside a blocked area, and whether or not the address matches an address stored in a retry register. When the requested address does not match the address in the retry register, the PCI to PCI bridge mistakes the access request for an access to a P.sub.-- PCI device. Thus, the PCI to PCI bridge positively decodes the access request on the S.sub.-- PCI bus, and transmits an access request on the P.sub.-- PCI bus. However, since none of the P.sub.-- PCI devices do not decode the request, the PCI to PCI bridge has to terminate the bus cycle on the P.sub.-- PCI bus by master abort. At this time, the PCI to PCI bridge stores the requested address in the retry register, and terminates the bus cycle on the S.sub.-- PCI bus in the retry manner. Following this, although the S.sub.-- PCI device tries again to access the S.sub.-- ISA device, the PCI to PCI bridge refers to the address in the retry register and does not decode the access request. Since none of devices on the S.sub.-- PCI bus positively decodes the access request, the PCI to ISA bridge subtractively decodes the request. As a result, the access request is transmitted to the S.sub.-- ISA bus, and the S.sub.-- ISA device can decode this request, thereby establishing a correct bus cycle.

REFERENCES:
patent: 5568621 (1996-10-01), Wooten
patent: 5621900 (1997-04-01), Lane et al.
patent: 5737765 (1998-04-01), Shigeeda
patent: 5748918 (1998-05-01), Cho et al.
patent: 5781748 (1998-07-01), Santos et al.
patent: 5864688 (1999-01-01), Santos et al.
patent: 5878237 (1999-03-01), Olarig

Affiliated with

Also associated with

Rating

Data transfer method between buses, bridge devices for interconn does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Data transfer method between buses, bridge devices for interconn, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Data transfer method between buses, bridge devices for interconn will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2078808