状态机电路，驱动步进马达的四相控制线圈A、B、C、D。马达向前 的四相控制线圈通电过程为：A-AB-B-BC-C-CD-D-DA-A…,后退的过程为A-DA-D-DC -C-BC-B-AB-A…,输入时钟信号CLK和DIR方向控制端控制马达的前进和后退。 -The state machine circuit, the driving of the stepping motor, the four-phase control coils A, B, and C, and D. The mo