Asynchronous serial port communication baud rate automatic detection device and method

The invention discloses an asynchronous serial port communication baud rate automatic detection device and method. The detection device comprises an edge detection module, a pulse width counting module, a minimum pulse width module and a table look-up module which are connected in sequence. The detection method comprises the following steps: receiving an asynchronous serial port signal, and sampling the asynchronous serial port signal through a sampling clock signal with a fixed frequency to obtain a rising edge signal and a falling edge signal of the asynchronous serial port signal; generating a counting enable signal according to the rising edge signal or the falling edge signal, and obtaining the effective time length of the enable signal in real time to obtain a high-level or low-levelbit width count value; comparing the high-level or low-level bit width count value with the minimum pulse width count value, and outputting a smaller value ; and querying a Baud rate and bit width relation table stored in the minimum pulse width module according to the value output by the minimum pulse width module to obtain the Baud rate of the asynchronous serial port sending data.