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help me with pic 16f877a

Discussion in 'The Projects Forum' started by emad shaaban, Apr 10, 2012.

  1. emad shaaban

    Thread Starter New Member

    Apr 10, 2012
    dear sir
    i need a help in Electric lock system to control 3 realy by pass code.
    plz see the attches (1)
    i made the programe with flowcode and test it with proteus v7 where it has work correctey
    but when i apply it to the circiut the LCD just show squares only, note when i try to make simple prog- for start LED just to test the pic ,it was not work in micro
    the fuses i use it for the programmer is in attache (2).
    i need any help please


    Last edited by a moderator: Apr 10, 2012
  2. Felo


    Feb 20, 2012
    VEE in the contrast control pin, you should put a trimpot in it (1 pin trim = 5v, middle pin trim = VEE, 3 pin trim = GND) you have this pin pulled to GND wich meas max contrast, therefore, you will only see black squares.

    Good luck
  3. emad shaaban

    Thread Starter New Member

    Apr 10, 2012
    I thank you very much mr Felo for the fast reply,second the circuit wiring has been test before with other pic (long time) which means the wiring is ok, my porblme that not programe could work in real,i tried to use an other pic and other programmer but all the same resultes , plz help.