| 摘要 |
<p>PURPOSE:To attain low power consumption in all positions whose power consumption is changed in accordance with frequency by making it possible to set up frequency to be used by a microinstruction even when the external clock of a CPU is fixed. CONSTITUTION:Clocks inputted from a clock input pin 1 are counted by a counter 3 and its count value is inputted to a comparator 5. On the other hand, a clock frequency dividing value executed by a microinstruction outputted from the CPU is stored in a frequency dividing register 4 through the internal data bus of the CPU. The comparator 5 compares the count value of the counter 3 with the value of the register 4, and when both the values are equal, outputs an equal signal. The counter 3 is reset by the equal signal and restarts counting. A frequency dividing clock specified by an AND gate 6 for ANDing with the equal signal and the input clock is outputted as a clock signal 7, which is supplied to a CPU function part 2.</p> |
