步进电机为四相单四拍,8255输出步进电机驱动信号，电机线圈A、B、C、D四相由8255的PC口PC0-PC3控制，逆时针：D→DC→C→CB→B→BA→A→AD→D→…,顺时针：DA→A→AB→B→BC→C→CD→D→DA→…

键盘0~9控制转速，B或C控制方向，F退出

数码管显示S.SPEED- i，i为转速-Four-phase stepper motor is a single four-beat, 8255 stepper motor drive output signal, the motor coils A, B, C, D four-phase by the 8255 PC port PC0-PC3 control, counter-clockwise: D → DC → C → CB → B → BA → A → AD → D → ..., clockwise: DA → A → AB → B → BC → C → CD → D → DA → ... keyboard control the speed of 0 to 9, B and C to control the direction, F exit the Digital display S.SPEED-i, i is the speed