hi,

1: org 0000h
2: mov dptr,#0F003H
3: mov a,#10000000B
4: movx @dptr,a
5: mov dptr,#0F000H
6: mov a,#0AAH
7: movx @dptr,a
8: end

the 3rd line in the above code initialize the 8255 control word. Even though if i used a driver (transistor) all the 8 LED connected to port A lits up when i send the byte #0AAH. Also, i tried to make the port A as input and connected some of its pin to +5v and some of it to 0V. When i tried to read the portA, nothing is read. So what could be the reason.


thanks
george