An electronic device such as a digital still camera includes a plurality of processing units for processing data and a memory for storing data. Each processing unit reads data from the memory and writes processed data into the memory. These accesses to the memory are asynchronously occurred. There is a case where access requests from the processing units to the memory contend with each other. To address such a contention, the electronic device includes an arbitration device. The arbitration device is arranged between a plurality of processing units and a memory and arbitrates requests to access the memory. Japanese National Phase Laid-Open Patent Publication No. 2002-508099 and Japanese Laid-Open Patent Publication Nos. 2005-250653 and 2002-312309 describe examples of such an arbitration device.
The number of processing units arranged in an electronic device increases due to, for example, multifunctional purposes. Any increase in the number of processing units causes an increase in power consumed by the electronic device. There is a demand for a reduction in power consumption in the electronic device.