刚开始学习LED显示屏，现在想使用1/8扫描方式在16*128的led显示屏上显示16*16字模的汉字，程序运行上面8行可正确显示，下面8行处于全部点亮状态，请高手赐教！！谢谢！
显示程序如下：
    void _display()
   {
       int i,j,k,yu,cu;
     for(i=0; i<16; i++)
      {  
                IOSET = LED_EN;   
                        for(j=0; j<128; j++)
                        {   
                                yu = j%16;
                                cu = j/16;
   
   
                            if(yu>=8)
                            switch((DB[cu][2*i+1] >> (7-(yu-8))) & 0x01)
                            {
                                    case 1:
                                        IOCLR = LED_R1;
                                        break;
                                    case 0:
                                        IOSET = LED_R1;
                                        break;
                            }
                            else
                            switch((DB[cu][2*i] >> (7-yu)) & 0x01)
                            {
                                    case 1:
                                        IOCLR = LED_R1;
                                        break;
                                    case 0:
                                        IOSET = LED_R1;
                                        break;
                                    }
                                IOCLR = LED_SCK;
                                IOSET = LED_SCK; //移位脉冲        
                                       
                        }   
                        IOCLR = LED_EN;
                        IOCLR = LED_RCK;
                        IOSET = LED_RCK;    //锁存信号

                           IOPIN = (IOPIN & 0xff0fffff) |(i << 20); //行选择
                        nDelay(10000);
                    }
                    
                    
        }