| CPC H03B 5/364 (2013.01) [H03B 5/04 (2013.01); H03B 5/326 (2013.01)] | 7 Claims | 

| 
               1. A circuit device comprising: 
            a first terminal and a second terminal coupled to a resonator; 
                a third terminal; 
                a fourth terminal to which a clock signal from an oscillation circuit is input; 
                a first switch provided on a signal path between the first terminal and the third terminal; 
                a second switch provided on a signal path between the second terminal and the fourth terminal; and 
                a register configured to output a signal for controlling the first switch and the second switch to be turned on or off, wherein 
                in a first mode, the first switch and the second switch are turned off, a control signal is input to the third terminal, and the clock signal is output from the fourth terminal, and 
                in a second mode, the first switch and the second switch are turned on. 
               |