Bus controller and information processing device providing reduced idle cycle time during synchronization
First Claim
1. A bus controller for controlling an access to a bus connected to a first device which operates in synchronization with a first clock signal and a second device which operates in asynchronization with the first clock signal, the controller comprising:
- a detector for receiving an access request from a central processing unit which operates in synchronization with a second clock signal different from the first clock signal and for detecting whether the access request represents an access to the first device or an access to the second device, the detector including a synchronous clock data storage section having synchronous clock data stored therein indicative of whether an access controlling signal is to be generated in synchronization with the first clock signal or the second clock signal; and
an access controlling signal generator, responsive to the detector, for generating a first access controlling signal for controlling an access of the first device to the bus in synchronization with the first clock signal and for supplying the first access controlling signal to the first device in a case where the access request represents the access to the first device, the access controlling signal generator generating a second access controlling signal for controlling an access of the second device to the bus in synchronization with the second clock signal and for supplying the second access controlling signal to the second device in a case where the access request represents the access to the second device.
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Accused Products
Abstract
A bus controller controls an access to a bus connected to a first device which operates in synchronization with a first clock signal and a second device which operates in asynchronization with the first clock signal. The controller includes a detector. The detector receives an access request from a central processing unit which operates in synchronization with a second clock signal different from the first clock signal to detect whether the access request represents an access to the first device or an access to the second device. The controller further includes an access controlling signal generator. The access controlling signal generator generates a first access controlling signal for controlling an access of the first device to the bus in synchronization with the first clock signal and for supplying the first access controlling signal to the first device, in a case where the access request represents the access to the first device. The access controlling signal generator generates a second access controlling signal for controlling an access of the second device to the bus in synchronization with the second clock signal and for supplying the second access controlling signal to the second device, in a case where the access request represents the access to the second device.
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Citations
14 Claims
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1. A bus controller for controlling an access to a bus connected to a first device which operates in synchronization with a first clock signal and a second device which operates in asynchronization with the first clock signal, the controller comprising:
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a detector for receiving an access request from a central processing unit which operates in synchronization with a second clock signal different from the first clock signal and for detecting whether the access request represents an access to the first device or an access to the second device, the detector including a synchronous clock data storage section having synchronous clock data stored therein indicative of whether an access controlling signal is to be generated in synchronization with the first clock signal or the second clock signal; and an access controlling signal generator, responsive to the detector, for generating a first access controlling signal for controlling an access of the first device to the bus in synchronization with the first clock signal and for supplying the first access controlling signal to the first device in a case where the access request represents the access to the first device, the access controlling signal generator generating a second access controlling signal for controlling an access of the second device to the bus in synchronization with the second clock signal and for supplying the second access controlling signal to the second device in a case where the access request represents the access to the second device. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An information processing device comprising a processor for receiving a first clock signal, a first device operating in synchronization with the first clock signal, a second device operating in asynchronization with the first clock signal and a bus for connecting the processor, the first device and the second device with each other,
the processor including: -
a frequency synthesizer for generating a second clock signal different from the first clock signal based on the first clock signal; a central processing unit for operating in synchronization with the second clock signal; and a bus controller for controlling an access to the bus, the bus controller including; a detector for receiving an access request from the central processing unit and for detecting whether the access request represents an access to the first device or an access to the second device, the detector including a synchronous clock data storage section having synchronous clock data stored therein indicative of whether an access controlling signal is to be generated in synchronization with the first clock signal or the second clock signal; and an access controlling signal generator, responsive to the detector, for generating a first access controlling signal for controlling an access of the first device to the bus in synchronization with the first clock signal and for supplying the first access controlling signal to the first device, in a case where the access request represents the access to the first device, the access controlling signal generator generating a second access controlling signal for controlling an access of the second device to the bus in synchronization with the second clock signal and for supplying the second access controlling signal to the second device, in a case where the access request represents the access to the second device. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification