Scheme capable of dynamically adjusting sensor frame rate according to polling rate of microcontroller to avoid invalid displacement data report and to save more power

A navigation sensor circuit to be externally coupled to a microcontroller, comprising:

• an image sensor, for operating and capturing images to generate and output displacement data based on a sensor frame rate;
• a specific counter;
• and
• a control circuit, coupled to the image sensor and the specific counter, for:
• monitoring at least one polling request signal sent from the microcontroller during a variable time interval;
• calculating at least one polling rate of the microcontroller according to the at least one polling request signal;
• and
• dynamically adjusting the sensor frame rate according the at least one polling rate;
• wherein a time length of the variable time interval is proportional to a programmable threshold, and the specific counter is started by the control circuit to count a number of signal receptions of the at least one polling request signal and is reset by the control circuit when a counting number of the specific counter is higher than the programmable threshold.