说明：  STM32外接旋转编码器（EC11），外部中断方式识别出正反转，响应速度优良，无丢步现象，无需延时滤波。在强干扰环境下测试正常。注意是仪器仪表面板常见的那种编码器，不是电机测速的那种。
(STM32 Read Encoder (EC11), external interrupt mode to recognizes positive and negative rotation, response speed is excellent, no step loss, no delay use. The programme runs properly in strong interference environment. Notice that the code is used for common type of encoder in instrument panel and the encoder is not the type used for motor's speed measurement.)