1. ugeshkumar

    Thread Starter New Member

    Nov 27, 2015
    16
    0
    I have microcontroller circit +3.3v input supply ,gpio pins i take out to interface to another board. in thar board have +5v supply only, I want to interface push button switch external. How to connect +5v pushbutton to microcontroller (because its operating voltage +3.3v)
    Please share circuits.
     
  2. spinnaker

    AAC Fanatic!

    Oct 29, 2009
    4,866
    988
    Look up "voltage divider". Basically two resistors. You will find calcualtors online.
     
  3. spinnaker

    AAC Fanatic!

    Oct 29, 2009
    4,866
    988
    You could also put a couple of diodes in series if you can find 2 with 1.5 voltage drop. Your mcu should be able to handle a 0-3 V differential.

    And you can even use several diodes if you like. Just have their voltage drops add up to the right voltage.
     
  4. ugeshkumar

    Thread Starter New Member

    Nov 27, 2015
    16
    0

    Hi

    If I use voltage divider to make 3.3v ,but i m 5v 1amps using, its going to damage controller.?
     
  5. spinnaker

    AAC Fanatic!

    Oct 29, 2009
    4,866
    988
    The circuit will only use the amps required. You could have a 5V 200 amp source and it will not matter. So know it will not damage it as long as you hook everything up correctly.
     
  6. ugeshkumar

    Thread Starter New Member

    Nov 27, 2015
    16
    0

    Can u pls share the circuit using with diode?
     
  7. spinnaker

    AAC Fanatic!

    Oct 29, 2009
    4,866
    988
    Just diodes wired in series. A 1n4004 is fairly common. They have a .7 forward voltage, so 3 should work. That will give you 2.9V.

    Also check your datasheet for the mcu. Some will have a few 5V inputs.
     
Loading...