if(dir==0) //如果为逆时针旋转
temp=7-step;//调换节拍信号
switch(temp)//8个节拍控制:(A+)->(A+B+)->(B+)->(B+A-)->(A-)->(A-B-)->(B-)>(B-A+)
{
case 0: IN_A=1;IN_B=0;IN_C=0;IN_D=0;break;
case 1: IN_A=1;IN_B=0;IN_C=1;IN_D=0;break;
case 2: IN_A=0;IN_B=0;IN_C=1;IN_D=0;break;
case 3: IN_A=0;IN_B=1;IN_C=1;IN_D=0;break;
case 4: IN_A=0;IN_B=1;IN_C=0;IN_D=0;break;
case 5: IN_A=0;IN_B=1;IN_C=0;IN_D=1;break;
case 6: IN_A=0;IN_B=0;IN_C=0;IN_D=1;break;
case 7: IN_A=1;IN_B=0;IN_C=0;IN_D=1;break;
default: IN_A=0;IN_B=0;IN_C=0;IN_D=0;break;//停止相序
}
}