u8 Read_ADS(u16 *x,u16 *y)
{
u16 xtemp,ytemp;
xtemp=ADS_Read_XY(CMD_RDX); //CMD_RDX=0XD0;
ytemp=ADS_Read_XY(CMD_RDY); //CMD_RDY=0X90
if(xtemp<100||ytemp<100)return 0;//读数失败
*x=xtemp;
*y=ytemp;
return 1;//读数成功
}
//2次读取ADS7846,连续读取2次有效的AD值,且这两次的偏差不能超过
//50,满足条件,则认为读数正确,否则读数错误.
//该函数能大大提高准确度
#define ERR_RANGE 50 //误差范围
u8 Read_ADS2(u16 *x,u16 *y)
{
u16 x1,y1;
u16 x2,y2;
u8 flag;
flag=Read_ADS(&x1,&y1);
if(flag==0)return(0);
flag=Read_ADS(&x2,&y2);
if(flag==0)return(0);
if(((x2<=x1&&x1<x2+ERR_RANGE)||(x1<=x2&&x2<x1+ERR_RANGE))//前后两次采样在+-50内
&&((y2<=y1&&y1<y2+ERR_RANGE)||(y1<=y2&&y2<y1+ERR_RANGE)))
{
*x=(x1+x2)/2;
*y=(y1+y2)/2;
return 1;
}else return 0;
}
以上的代码中红色部分的返回值是1,但是x1,x2,y1,y2的值是怎么确定下来的?返回的值只是1或者0啊
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