Pointer device

A pointer device, adapted for an electromagnetic coordinate positioning apparatus, the pointer device comprising:

• an induction coil, configured to couple to an excitation magnetic field formed by the electromagnetic coordinate positioning apparatus to generate a power supply in a power storage period, and receive an instruction signal from the electromagnetic coordinate positioning apparatus in an instruction receiving period, the instruction signal comprising a fixed quantity of bits;
• a clock generating circuit, electrically-coupled to the induction coil and configured to generate a clock signal according to operation of the power supply;
• and
• a control circuit, electrically-coupled to the induction coil and the clock generating circuit, and configured to:
• decode the instruction signal in the instruction receiving period according to the clock signal after the power storage period to parse whether the instruction signal is one of a plurality of predefined instructions, wherein when the instruction signal is one of the plurality of predefined instructions, the control circuit triggers, in a data transmission period, the induction coil to send a data signal corresponding to the instruction signal to the electromagnetic coordinate positioning apparatus according to the clock signal after the instruction receiving period, the data signal comprising a fixed quantity of bits, and the induction coil respectively sends the bits of the data signal at different time slots in the data transmission period, to respond to the instruction signal,
• wherein the power storage period, the instruction receiving period, and the data transmission period each have a fixed time length.