Max232

Discussion in 'General Electronics Chat' started by Dritech, Oct 23, 2013.

  1. Dritech

    Thread Starter Well-Known Member

    Sep 21, 2011
    756
    5
    Hi,

    I will be using the MAX232 to interface Visual Studio with the PIC18F4550 using UART. While doing my research I came across this tutorial:

    http://www.scienceprog.com/alternatives-of-max232-in-low-budget-projects/

    He connected 2 LEDs with the RT and TX pins. Can there cause data errors or cause some kind of interference ??

    Also, some MAX232 circuits are using 1uF capacitors and others are using 10uF. Does this really make any difference??

    Thank in advance.
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,446
    3,362
    The two LEDs should not cause any problem.

    Some RS232 converters require no capacitors, some 0.1μF, 1μF and 10μF caps.
    Consult the datasheet of the device you are using.
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,553
    2,375
    The high slew rate version (MAX232A) uses 0.1μF, the Maxim and TI site both specify 1μF for the general purpose version, I have found it not all that critical above 1μF.
    Max.
     
  4. Dritech

    Thread Starter Well-Known Member

    Sep 21, 2011
    756
    5
    Thanks for the replies.
     
  5. Dritech

    Thread Starter Well-Known Member

    Sep 21, 2011
    756
    5
    Is there the need to ground unused pin please?
     
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,553
    2,375
    I never have and I have been using it for some years now in different applications, It would not hurt if you do want GND them, as long as you are not monitoring the Hardware Handshake on the other end!
    Max.
     
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