A novel PLL is provided. An oscillator circuit includes first to n-th inverters, and first and second circuits. A first terminal of each of the first and second circuits is electrically connected to an output terminal of the i-th inverter. A second terminal of each of the first and second circuits is electrically connected to an input terminal of the (i+1)-th inverter. The first circuit has functions of storing first data, switching between electrically disconnecting the first terminal and the second terminal from each other and setting a resistance between the first terminal and the second terminal to a value based on the first data. The second circuit has functions of storing second data, switching between electrically disconnecting the first terminal and the second terminal from each other and setting a resistance between the first terminal and the second terminal to a value based on the second data.