PIC Output Pin Voltage Problems

Discussion in 'Embedded Systems and Microcontrollers' started by ajl5102, Apr 25, 2010.

  1. ajl5102

    Thread Starter New Member

    Apr 11, 2010
    I am using a PIC18f14K50 to source current to 4 LEDS. The data sheet says that each I/O pin can source/sink 25mA. However, all the ports combined can not source more than 95mA. I am using current limiting resistors to limit each LED to a max of 15mA per I/O. Well within the pin as well as entire PIC specs.

    Anyway, after programming and testing the PIC, I am only receiving approx 2V from two of the pins and 0V at the other two. Right now, I am thinking I may have messed up the pin addressing for the two pins at 0V, but as for the other two pins I am not sure why their output is only 2V. The data sheet says when running a high output, Vdd will be at that pin.

    Am I missing something here? Any suggestions/troubleshooting for the 2V out of a high (Vdd) output pin?
  2. ajl5102

    Thread Starter New Member

    Apr 11, 2010
    O yeah, my Vdd is 4.5V. Forgot to mention. Thanks in advance for any suggestions.
  3. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
    Post your schematic.
  4. t06afre

    AAC Fanatic!

    May 11, 2009
    Also the code you are using. Even if it only put a constant on some port. Then we can check if your register setting is correct
  5. kingdano

    Senior Member

    Apr 14, 2010
    you should try only 2 LEDs and then 3....see if there is a cut-off point.