| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To reduce a cost of a system by removing an oscillation circuit from a slave device by controlling a supply of a clock signal from a master device to the slave device. <P>SOLUTION: The master device (portable information terminal) comprises an oscillation circuit 27 for generating a clock signal, and an OR circuit 32 and an AND circuit 34 for supplying to the slave device (card adopter) a clock signal generated by the oscillation circuit 27 at the time a start signal or a clock control signal is input from the slave device when accessing to the slave device, and a bus control circuit 30 for performing data transfer in synchronization with the clock signal, and the slave device comprises a communication control circuit 40 for receiving the clock signal supplied from the master device and performing data transfer in synchronization with the clock signal, and a clock control signal generation circuit 42 for generating a clock control signal for controlling a supply of the clock signal and transmitting the same to the master device. <P>COPYRIGHT: (C)2003,JPO</p> |
