求大神指点哪儿错了？KEIL一直提示DHT11.C(58): error C202: ✀P2_0✀: undefined identifier

这是程序 求大神帮帮忙typedef unsigned char U8; typedef unsigned int U16;sbit P2_0 =P3^7;U8 U8FLAG,U8temp;U8 U8T_data_H,U8T_data_L,U8RH_data_H,U8RH_data_L,U8checkdata;U8 U8T_data_H_temp,U8T_data_L_temp,U8RH_data_H_temp,U8RH_data_L_temp,U8checkdata_temp;U8 U8comdata;void Delay(U16 z){ U8 x,y; for(x=z;x>0;x--) for(y=110;y>0;y--);} void Delay_10us(void) { U8 i; i--; i--; i--; i--; i--; i--; }void COM(void){ U8 i; for(i=0;i<8;i++) { U8FLAG=2; while((!P2_0)&&U8FLAG++); Delay_10us(); Delay_10us(); Delay_10us(); U8temp=0; if(P2_0)U8temp=1; U8FLAG=2; while((P2_0)&&U8FLAG++); if(U8FLAG==1)break; U8comdata<<=1; U8comdata|=U8temp; } }void RH(void){ data=0; Delay(34); P2_0=1; Delay_10us(); Delay_10us(); Delay_10us(); Delay_10us(); P2_0=1; if(!P2_0) { U8FLAG=2; while((!P2_0)&&U8FLAG++); U8FLAG=2; while((P2_0)&&U8FLAG++); COM(); U8RH_data_H_temp=U8comdata; COM(); U8RH_data_L_temp=U8comdata; COM(); U8T_data_H_temp=U8comdata; COM(); U8T_data_L_temp=U8comdata; COM(); U8checkdata_temp=U8comdata; P2_0=1; U8temp=(U8T_data_H_temp+U8T_data_L_temp+U8RH_data_H_temp+U8RH_data_L_temp); if(U8temp==U8checkdata_temp) { U8RH_data_H=U8RH_data_H_temp; U8RH_data_L=U8RH_data_L_temp; U8T_data_H=U8T_data_H_temp; U8T_data_L=U8T_data_L_temp; U8checkdata=U8checkdata_temp; } }}