| 摘要 |
<p>PURPOSE:To automatically perform the speed change of a reference synchronizing signal in a main control circuit corresponding to the speed of peripheral circuits by controlling the speed of the reference synchronizing signal in the main control circuit by detecting the access of the main control circuit to each peripheral circuit. CONSTITUTION:A chip select signal from an address decoder 15 is also inputted to an access control circuit 12. The response speed of each of the peripheral circuits 11a, 11b... for the access of a CPU 10 that is the main control circuit is set differently from each other. The access control circuit 12 decides to which peripheral circuit the access is made, and adjusts the clock speed of the CPU 10 corresponding to a decided result via an access control signal 3. In such a way, it is not required to change the software of the main control circuit even when the synchronizing signal of the main control circuit is accelerated since the reference synchronizing signal of the main control circuit is changed corresponding to the response speed of a peripheral device automatically by hardware.</p> |
