Electrical computers and digital data processing systems: input/ – Intrasystem connection – Bus access regulation
Reexamination Certificate
1995-05-08
2001-09-11
Verbrugge, Kevin (Department: 2185)
Electrical computers and digital data processing systems: input/
Intrasystem connection
Bus access regulation
C710S100000
Reexamination Certificate
active
06289408
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an address mask register which is used as a look-up to determine whether an address currently on an address bus should be acted upon.
BACKGROUND OF THE INVENTION
Components in computer systems generally communicate over a bus. While at one time systems had only one bus, multiple bus architectures operating within multiple processor system environments have become more common. As a result, bus interfaces or bridges are needed between two buses to facilitate the transfer of data from one bus to another.
In some programming applications, it is desired that the bus interface only pass certain addresses on to target devices and ignore other addresses. Some systems for accomplishing this result can be unduly complex. It would thus be advantageous to have a simple and easily implemented system for providing an indication as to which addresses should be passed on to targets.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a mask register which is used as a look-up means for determining whether an address currently on the address bus should be sent to a target device, or whether the address currently on the bus should be ignored.
According to one embodiment of the present invention, an address mask register for defining a range of addresses to which a bus interface will respond is disclosed. The address mask register has two fields: a coarse address select field and a fine address select field. The coarse address select field defines which coarse regions of memory are transferred from a first bus to a second bus by the bus interface. The fine address select field defines which fine regions of memory are transferred from the first bus to the second bus by the bus interface.
According to another embodiment of the present invention, a method for determining whether a bus interface should pass information from a first bus to a second bus based upon the address associated with the information is disclosed. First, each target device on the first and second buses is assigned a different memory address. The assigned memory addresses are then stored in said bus interface in an address mask register. When a request is received at said bus interface to transfer information from said first bus to a target device on the second bus, the address associated with the information is compared with the addresses set in the mask register. The information is transferred from the first bus to the target device on the second bus when the address associated with the information is stored in the address mask register.
REFERENCES:
patent: 4853846 (1989-08-01), Johnson et al.
patent: 5088028 (1992-02-01), Theus et al.
patent: 5287452 (1994-02-01), Newman
patent: 5513337 (1996-04-01), Gillespie et al.
Apple Computer Inc.
Burns Doane Swecker & Mathis L.L.P.
Verbrugge Kevin
LandOfFree
Bus interface with address mask register for transferring... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bus interface with address mask register for transferring..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bus interface with address mask register for transferring... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2502148