Abstract: A control system of desktop 3D printer was designed with DSP2812 digital signal processing chip as the core controller. By generating non-symmetric pulse width modulation (PWM) waveform with the general-purpose registers of the DSP2812, and using general-purpose input/output (I/O) port to control the stepper motor driver chip, the velocity and displacement control of the stepper motor was achieved. Another innovative application was using DSP2812’s general-purpose digital I/O port to achieve universal inter-integrated circuit (I2C) function, and then to control the stepper motor’s starting current, which could reduce system power consumption and improve control accuracy and stability of the stepper motor.