说明：  本次课程设计利用软件定时方式采用Intel 8255A可编程外设接口芯片唐都TD-PITC 实验系统上模拟直流电动机闭环调速系统，A/D转换器实现模拟信号到数字信号的转换，设置电机转速的给定值，通过PWM方式可实现电机转速的调节，LED灯显示电机转速的大小状态。
(The curriculum design using software timing mode analog closed-loop DC motor speed control system on the Intel 8255A programmable peripheral interface chip Tangdu TD-PITC experimental system, the A/D converter analog signal to digital signal conversion, set the motor speed a given value, the regulation of the motor speed can be realized by the PWM method, the LED light shows the status of the size of the motor speed.)