Variable slot configuration for multi-speed bus
First Claim
1. A method for operating a device bus, said device bus being arranged to have a number of devices connected thereto, said device bus being arranged to be connected to a clock signal source, said clock signal source being selectively operable to provide a plurality of clock signals with each of said clock signals having a different frequency, said method comprising:
- determining said number of said devices being connected to said device bus; and
applying one of said clock signals to all devices connected to said device bus, said one of said clock signals being determined depending upon said number of said circuit devices being connected to said device bus.
1 Assignment
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Accused Products
Abstract
A method and apparatus are provided in which a control scheme is implemented to enable a PCI bus to operate more than two PCI slots into which PCI devices may be installed. The PCI slots are checked to determine if a PCI device is installed in the slots and the speed at which the installed PCI devices are capable of running. If any of the slots has a 33 MHz device installed in any of the slots, the system is enabled to run more than two slots, and all of the PCI devices will run at 33 MHz. When no 33 MHz cards or devices are installed in the PCI slots, and PCI devices are only installed in the first two slots, then the system is enabled to run only the first two slots at the speed of 66 MHz. In one alternative embodiment, a default configuration routine sets the PCI bus speed at one of the operating frequencies and modifies that default if it is determined during a system configuration cycle that another speed is more appropriate.
66 Citations
17 Claims
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1. A method for operating a device bus, said device bus being arranged to have a number of devices connected thereto, said device bus being arranged to be connected to a clock signal source, said clock signal source being selectively operable to provide a plurality of clock signals with each of said clock signals having a different frequency, said method comprising:
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determining said number of said devices being connected to said device bus; and applying one of said clock signals to all devices connected to said device bus, said one of said clock signals being determined depending upon said number of said circuit devices being connected to said device bus.
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2. A method for operating a device bus, said device bus being arranged to have circuit devices connected thereto, said device bus being arranged to be connected to a clock signal source, said clock signal source being selectively operable to provide at least first and second clock signals at first and second frequencies, respectively, to said circuit devices connected to said device bus, said method comprising:
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determining a device number, said device number being representative of a number of said circuit devices being connected to said device bus; applying said first clock signal to all circuit devices connected to said device bus if said device number exceeds a first predetermined number; and applying said second clock signal to all circuit devices connected to said device bus if said device number is less than a second predetermined number. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for operating a device bus, said device bus being arranged to have circuit devices connected thereto, said device bus being arranged to be connected to a clock signal source, said clock signal source being selectively operable to provide at least first and second clock signals at first and second frequencies, respectively, to said circuit devices connected to said device bus, said method comprising:
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configuring said device bus for operation at said first frequency; determining that all said circuit devices connected to said device bus are capable of running at said second frequency; determining that all of said circuit devices connected to said device bus is less than a predetermined number; resetting said circuit devices to operate at said second frequency; and resetting said device bus to run at said second frequency.
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16. An information processing system comprising:
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a CPU device; a system bus, said CPU device being coupled to said system bus; a device bus; a bridge circuit connected between said system bus and said device bus, said device bus being coupled to a plurality of connection slots, said connection slots being arranged for selectively providing connection of said circuit devices to said device bus; first detection means coupled to said connection slots, said first detection means being arranged for detecting which of said connection slots contain circuit devices; second detection means coupled to said connection slots, said second detection means being arranged for detecting a frequency at which said circuit devices are capable of running; and clock control means coupled to said first and second detection means and said connection slots, said clock control means being selectively operable in response to outputs from said first and second detection means for selectively applying one of first or second clock signals to said circuit devices. - View Dependent Claims (17)
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Specification