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
P3.5
Sorry for the delay, but I am being very precise in my typing so that I don't introduce anything typos that might cause confusion.
Is the following what you're seeing?
| (wire) P3.5 |------------------------------- | ^ ^ | | 0V 5V
If it is, then I think you should check the conductor.
nice explanation but i am measuresing the voltage at the controller pin only so that may not be the problem. i cheacked the same thing on the different board but the same thing happenning
"i cheacked the same thing on the different board but the same thing happenning"
Is that another board to the same design, or a completely different board?
If it's another board to the same design, Could it be a design error - so that both boards have the same problem?
If the at89c55wd is in a socket, remove it and check for shorts to ground...
If the at89c55wd is in a socket yes its in socket i cheacked socket pin and controller pin continuty on multimeter and its fine.
"i cheacked socket pin and controller pin continuty on multimeter and its fine."
What you need to check is for shorts or whatever on the board that are keeping the pin pulled down!
BTW: the spelling is "checked"
i checked it with ground there no shorting nothing wrong with it the port is pullup by 10kohms.