io.c

单片机应用开发实例.rar

sfr P1 = 0x90;                              //定义Port 1 
sfr P3 = 0xB0;                             //定义Port 3 
void main (void)
{
unsigned char pval;     
P1 = 0xFF;                                //设置 P1 
//用调试器Toolbox 按钮改变P1
while (1)
        {
         pval = P1;                       // 读 P1 
        P3 = pval;                        // 写 P3 
       }
}