Multiplexing PWM pin with other outputs


Closed Thread
Results 1 to 3 of 3
  1. #1
    Join Date
    Feb 2003
    Location
    Sydney, Australia
    Posts
    126

    Default Multiplexing PWM pin with other outputs

    Hi All,

    Just running through a concept here. I have a button plate with LED feedback for each button.

    I want to use the PWM output used to create a 'backlight' that will illuminate all the status leds at a lower level when the button feedback outputs are not high. The Backlight is driven from the PWM out from the 16f87 (via a transistor to produce the required drive for the 4 LEDS).

    First thought was to use a couple of diodes (poss schottkys to reduce the V drop) to act as an old school OR gate to drive the LEDs:
    (Cheesy ASCii art follows..)

    <code>
    PWM---[>|-----[>|--[___]---+5
    ...........| (LED) 560R
    LED---[>|--
    </code>

    Any comments before I proto it and see if I blow anything up ??

    Bill.

  2. #2
    Join Date
    Feb 2003
    Posts
    432


    Did you find this post helpful? Yes | No

    Default

    Change the "+5" to "0V" or it wont work at all
    Keith

    www.diyha.co.uk
    www.kat5.tv

  3. #3
    Join Date
    Feb 2003
    Location
    Sydney, Australia
    Posts
    126


    Did you find this post helpful? Yes | No

    Default

    Arr, mmm, yes

    that was a test. well done.
    8-)

Similar Threads

  1. 12F683 2 x PWM Outputs
    By retepsnikrep in forum mel PIC BASIC Pro
    Replies: 29
    Last Post: - 23rd July 2021, 20:20
  2. Is this a K Type sensor?
    By jessey in forum mel PIC BASIC Pro
    Replies: 20
    Last Post: - 21st November 2009, 13:55
  3. Microcontroller with 2 way paging application problem
    By oneohthree in forum mel PIC BASIC Pro
    Replies: 30
    Last Post: - 20th April 2007, 17:27
  4. Another RTC, DS1287
    By DavidK in forum Code Examples
    Replies: 0
    Last Post: - 12th December 2006, 17:07
  5. pwm to pin using variable
    By wsmrite in forum mel PIC BASIC Pro
    Replies: 3
    Last Post: - 7th April 2006, 17:08

Members who have read this thread : 1

You do not have permission to view the list of names.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts