US 8,799,699 B2Granted

Data processing system

AssigneeFujitsu Semiconductor Limited

InventorAkinori Hashimoto

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Abstract

Each of a plurality of master devices outputs a speed grade signal indicating a data transfer speed with a data transfer request. An arbiter arbitrates transfer requests and speed grade signals from the plurality of master devices. A clock enable generation circuit generates a clock enable signal with a varying ratio of a valid level according to the speed grade signal arbitrated by the arbiter. A slave device operates upon receiving a clock signal when the clock enable signal is at the valid level, and transfers data according to the transfer request arbitrated by the arbiter. Accordingly, the frequency of the clock signal which causes the slave device to operate may be changed for each transfer request, and a fine control of the power of the slave device may be easily performed. As a result, power consumption of the data processing system may be finely controlled.

Claims8

Dependent claims

A data processing system comprising:

a plurality of master devices configured to output data transfer requests and speed grade signals indicating data transfer speeds;
a plurality of arbiters each configured to arbitrate the transfer requests and the speed grade signals from the plurality of master devices;
a plurality of clock enable generation circuits each configured to generate a clock enable signal, a ratio of a period of a valid level of the clock enable signal varying in accordance with one of the speed grade signals arbitrated by the arbiters;
and
a plurality of slave devices each provided for a corresponding one of the arbiters and a corresponding one of the clock enable generation circuits, and each configured to operate upon receiving a clock signal when a corresponding clock enable signal is at the valid level and to transfer data according to one of the transfer requests arbitrated by the corresponding one of the arbiters,
wherein each of the plurality of master devices generates the speed grade signals according to a transfer mode of data with each process of generating the transfer requests.

3 more elements

Dependencies are inferred from the claim text.