hi to all i am using at89c55wd the problem is when i tried to toggle the P3 all bit i.e. P3.0,1,2,3,4,6,7 changes its state expect P3.5 i used timer 0 as timer after 1 sec i invert the P3. position by P3=~P3 but P3.5 unchanged all other toggle between 0 and 1.P3.5 toggle properly on simulator but not at h/w side.
i tried it by changing the perticuler bit i.e. P3.5 but did not work please help me
not on the scope but on multimeter it remains at mV i.e. at ground level i wrote a prog. only to assign 0xFF to P3 but level on P3.5 is low other at high. that means i am not able to pull the port3.5 to high level at any point
Sorry, I might misunderstand you ...
Are you saying that when you measure the voltage, at one end of the copper (CPU) you see one level and at the other end you see a different level?
If so, check the circuit and/or board for a missing link.
i can't get you. what you want say