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Thread: Apa102/sk9822

  1. #1

    Default Apa102/sk9822

    I know I had some responses from some who have used these before but was having an issue with the first led in a string going on with white after powering up. It's always nice to confirm what I did is a true fix so ....

    Before I had in the initialization code --
    LOW SDA
    LOW SCL both being held low before program starts and having the problem

    Changed it to
    HIGH SDA
    LOW SDA and (seemingly)(hopefully) that has fixed it.

    guessing these react to a low/high transition perhaps? anyway, like I say, always nice to confirm. --thanks

  2. #2
    Join Date
    Mar 2003
    Location
    Commerce Michigan USA
    Posts
    1,190

    Default Re: Apa102/sk9822

    Michael, What may be happening is, when power is applied to the strip and the processor at the same time the micro has ALL pins in a high impedance state. At that time there is an opportunity for the data and clock line to toggle unintendedly. I would tie the data and clock lines LOW thru a pull down resistor with maybe a 4.7K to give the lines a state during the reset time.
    Dave Purola,
    N8NTA
    EN82fn

  3. #3

    Default Re: Apa102/sk9822

    Ok Dave, thanks. I'll do that -- like I say, seems to be ok after many on/off cycles with setting the clock and data pins high in the initialization but I'll do what you suggest. thanks !

  4. #4
    Join Date
    Mar 2003
    Location
    Commerce Michigan USA
    Posts
    1,190

    Default Re: Apa102/sk9822

    Michael, after doing that, set the port pins LOW, That way you wont be inadvertently setting the clock line high or the data line high before sending REAL data.
    Dave Purola,
    N8NTA
    EN82fn

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