| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a clock control system for appropriately controlling whether or not a clock signal is to be supplied to a processor corresponding to the operating state of a device. SOLUTION: A device 1 for periodically accessing a system memory outputs a signal under Device operation showing a state under operating and a Device Request signal for requesting operation start to a device state monitoring circuit 3. On the other hand, the device state monitoring circuit 3 asserts an Enable signal during the operation of the device or asserts a Disable signal in the other case. When Stop Grant is asserted, a clock control circuit 5 asserts only STOPCLK for stopping only the internal clock of the processor and when the Stop Clock is asserted, PCLKSTP is asserted for stopping this STOPCLK and an external clock.</p> |
