| 摘要 |
PURPOSE:To decrease the number of pins of an IC by reading the frequency division ratio of a programmable frequency divider externally as serial data, and converting this serial data into parallel data and setting it as the frequency division ratio in the programmable frequency divider. CONSTITUTION:An input reading circuit 16 inputs a serial signal TP indicating the frequency division ratio of a programmable frequency dividing circuit 2c and a clock signal CL and they are stored as parallel data in a frequency division ratio storage circuit 14. The data in the frequency division ratio storage circuit 14 is written in a nonvolatile memory in the programmable frequency dividing circuit 2c, setting the frequency division ratio by the memory. |
