是倒着显示的。为什么显示出来有拖影，需要加多少的延时函数

void display3()               
{   
   uchar q;                        
   for(q=0;q<200;q++)
   {
    Lcd12864_Write16CnCHAR(16,0,"气勇要需造创");
    Lcd12864_Write8CnCHAR(q, 2,"sekat ytivitaerc");
    Lcd12864_Write8CnCHAR(q-128,2,"egaruoc");   
    Lcd12864_Write16CnCHAR(16,4,"成竟事者志有");
       Lcd12864_Write8CnCHAR(q, 6, "a si ereht erehw");
       Lcd12864_Write8CnCHAR(q-128,6,"a si ereht lliw");
    Lcd12864_Write8CnCHAR(q-130,6,"yaw");
       if(key==0) break;
}
}