| 摘要 |
PURPOSE:To operate a microprocessor muPC with a frequency programmed with respect to an input frequency from the external by providing a means which can change the frequency of an internal clock which determines the operation speed of the muPC. CONSTITUTION:When the frequency of an input clock signal X is f0, frequencies of output signals 7, 8, and 9 of FFs 4a, 4b, and 4c are f0/2, f0/4, and f0/8 respectively. When a clock select register 5 sets one of outputs 11-14 to the high level in accordance with a command 10 from the muPC, the clock signal of one of an input signal 6 of the FF4a and output signals 7-9 of FFs 4a-4c is selected. Clocks phi1 and phi2 obtained by dividing frequencies f0-f0/8 of external clock signals are obtained as internal clock signals 2 and 3. |
