The content that this text studies is to produce PWM control signal to realize the pace to the direct current motor and adjust and control through the one-chip computer. Originally design hardware and software that has mainly introduced this system to be designed specifically, and has done certain description to the hardware block-diagram and software flow diagram. Having designed the module AT89C51 chip of following function according to the hardware block-diagram, the systematic core controls the module, pass P1.3 port through P1.0, control, step down, cut wave circuit whom four brilliant floodgate in charge of coherent to come, adjust and control the armature voltage of the direct current motor while being broken:Step down and cut the circuit of wave and drive the module; Electric current measure, feedback; module pace measure, feedback; module protect circuit;module AT89C51 one-chip computer module.Adopts and combines the above the five module systematically, thus form a more intact and more effective direct current motor and adjust the control system of the speed. The system is reasonable in design, with perfect function, performance is superior, it is good to apply the result in actual production, control convenient, the configuration is simple and advantage that the flexibility is great.
Keywords: AT89C51；DC- motor；PWM speed control system
