Method for near field communication with serial interface microcontroller and nfc tag device using the same

An NFC tag device, comprising:

• an NFC LC resonant circuit, comprising a first terminal and a second terminal;
• a frequency dividing circuit, comprising an input terminal and an output terminal, wherein the input terminal of the frequency dividing circuit is coupled to the first terminal of the NFC LC resonant circuit;
• an envelope detecting circuit, comprising an input terminal and an output terminal, wherein the input terminal of the envelope detecting circuit is coupled to the first terminal of the NFC LC resonant circuit;
• a serial interface microcontroller, comprising a clock input terminal and a serial data input terminal, wherein the clock input terminal of the serial interface microcontroller is coupled to the output terminal of the frequency dividing circuit, and the serial data input terminal of the serial interface microcontroller is coupled to the output terminal of the envelope detecting circuit,
• wherein the frequency dividing circuit divides an NFC carrier signal from the first terminal of the NFC LC resonant circuit into an NFC clock signal,
• wherein the envelope detecting circuit converts the received signal into an envelope signal,
• wherein the clock input terminal of the serial interface microcontroller receives the NFC clock signal, and the serial data input terminal of the serial interface microcontroller receives the envelope signal, for decoding an NFC data from the envelope signal according to the NFC protocol.