我的28bjy-48步进电机用的是四相八拍的脉冲控制，为什么我只给了他128个脉冲他就转了一圈了呢？

程序如下：
#include<reg52.h>
#define uchar unsigned char
#define uint unsigned int

uchar code step_table[] = {0xfe,0xfc,0xfd,0xf9,0xfb,0xf3,0xf7,0xf6};

void delay(uchar z)
{
    uchar x,y;
    for(x = 114; x > 0; x--)
    for(y = z; y > 0; y--);
}

void main()
{
    uchar i = 0;
    uint j = 128;

        for(j = 128; j > 0; j--)
        {
            for(i = 0; i < 8; i++)
            {
                P1 = step_table[i];
                delay(20);
            }
        }
        while(1);
}