Servos have been widely used in robots in various fields and a plurality of toys. To keep functioning, servos are controlled by PWM signals constantly sent from a servo controller, but the controller often has its limitations in performance. A servo interface device comprising a CPLD is designed that not only provides simultaneous control over more servomotors, but can also compute and generate the PWM signals needed by the servos. In addition, the servo interface device can be directly integrated with another single chip to achieve division of control, in which the single chip takes care of sensing, communication, connection and other interactive functions while the CPLD provides multiple-axis servo control. More importantly, when the single chip is communicating with a computer or performing other external communication tasks, the normal operation of the servos will not be affected by brief pauses of the MCU resulting from the communication tasks.