Abstract: The method of rectangular single pulse based on serial port of MCU-51 is proposed to improve the precision of rectangular single pulse generated by traditional PWM (Pulse Width Modulation) and software delay. Control the MCU-51 serial communication port work in mode 3-nine asynchronous communication mode, send specific digital, use the special data framestructure of the serial communication to formadjustablerectangular single pulse; Set timer T2 in the baud rate generator mode, by controlling the serial port baud rate, to change the duration of each data bit and realize multiple pulse width values. The experimental data shows that the pulse width accuracy of the rectangular single pulse can achieve crystal accuracy.

Key words: serial port communication, single chip microcomputer(MCU), baud rate, rectangular single pulse