Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 7 of 7

Thread: Limit or pullup low voltage from interrupt

  1. #1

    Limit or pullup low voltage from interrupt

    Hi.

    Im controlling an Adafruit Neotrellis button/led board with Teensy.40

    https://learn.adafruit.com/adafruit-neotrellis 2

    I have a 4 x 8 boards grid soldered together.

    I have an issue with the interrupt pin.

    If I load only 1 board ( thou they are soldered together) it works fine. I messured the interrupt pin voltage and get

    Not button pressed 3.26 v
    Button pressed between 3.10 and 3.20 v and goes back to 3.26 v


    If I load 32 boards and messure the interrupt pin voltage I get

    Not button pressed 3.26 v
    Button pressed between 2.40 and 3.13 (mostly below 2.80) and back to 3.26v


    But from time to time in this case the voltage goes down to 0.80 and stays there until I press again a few time and goes back up to 3.26v

    I try PULL_UP in the code with no luck...

    Any Idea?

  2. #2
    Senior Member PaulStoffregen's Avatar
    Join Date
    Nov 2012
    Posts
    25,206
    Same project as your prior thread?

    https://forum.pjrc.com/threads/68395...its-Neotrellis

  3. #3
    Senior Member PaulS's Avatar
    Join Date
    Apr 2015
    Location
    Netherlands
    Posts
    695
    Quote Originally Posted by Moris526 View Post
    If I load only 1 board (thou they are soldered together) it works fine. I messured the interrupt pin voltage and get
    Not button pressed 3.26 v
    Button pressed between 3.10 and 3.20 v and goes back to 3.26 v
    How did you measure that INT pin voltage? With an oscilloscope or digital volt meter?
    I expect the INT pulse to be quite short, so a digital volt meter may not be able to catch that.

    I try PULL_UP in the code with no luck...
    No need for pinMode(INT_PIN, INPUT_PULLUP); as the board already has a 10K pull-up resistor mounted [R3 in the schematic].

    Paul

  4. #4
    Yes. Same project.

  5. #5
    Quote Originally Posted by PaulS View Post
    How did you measure that INT pin voltage? With an oscilloscope or digital volt meter?
    I expect the INT pulse to be quite short, so a digital volt meter may not be able to catch that.


    No need for pinMode(INT_PIN, INPUT_PULLUP); as the board already has a 10K pull-up resistor mounted [R3 in the schematic].

    Paul

    Code:
    void loop() {
      if (!digitalRead(INT_PIN)) {
        trellis.read();
        Serial.println("Hello");
      }



    With a digital volt meter. But I got those results. When it doesnt come back up, at 0.8 it keeps printing "Hello"

  6. #6
    Cant I put some code after trellis.read(false); to stop the If function no matter what?

  7. #7
    Administrator Paul's Avatar
    Join Date
    Oct 2012
    Posts
    418
    Continue this discussion on the original thread, where many of the basic troubleshooting questions have already been answered.

    DO NOT start duplicate threads!

    Every new message added to the original thread causes it to appear again at the top of "What's New" and the list of threads within each area.

Posting Permissions

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