void Nixie_Scan (unsigned char location,unsigned char num){
switch(location){
case 1:P2_4=1,P2_3=1,P2_2=1;break;
case 2:P2_4=1,P2_3=1,P2_2=0;break;//led7
case 3:P2_4=1,P2_3=0,P2_2=1;break;//led6
case 4:P2_4=1,P2_3=0,P2_2=0;break;//led5
case 5:P2_4=0,P2_3=1,P2_2=1;break;//led4
case 6:P2_4=0,P2_3=1,P2_2=0;break;//led3
case 7:P2_4=0,P2_3=0,P2_2=1;break;//led2
case 8:P2_4=0,P2_3=0,P2_2=0;break;