这是用CPLD开发的读取绝对式编码器反馈的信号的代码，读取电机的转子的绝对位置和判断转动方向对于电机控制很实用。,This is read by the CPLD Development absolute encoder feedback signal to the code, read the motor' s rotor position and to determine the absolute direction of rotation is very useful for motor control.