dimming led display from windows, M.B NUC7I7DNBE

Discussion in 'Digital Circuit Design' started by Константин Альфимов, Apr 1, 2019.

  1. Константин Альфимов

    Thread Starter New Member

    Apr 1, 2019
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    Hello! We want to start developing a device based on the NUC7I7DNBE motherboard. how to implement on the motherboard a software adjustment of the brightness of the screen backlight (slider in windows). Our display is NL192108BC18. Thank!
     
  2. danadak

    Distinguished Member

    Mar 10, 2018
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    This display has a pwm driver input for display brightness control.

    So you could -

    1) Use an Arduino and using Python message the Arduino to set its PWM
    values. Done over USB, maybe use mBlock to program.

    2) Possibly use motherboard chipset and develop a pwm signal from it. You
    would have to look at motherboard connections/pinout to see if you have
    access to that.

    3) Use MB optical IR interface, and an Arduino, Python, to control a PWM on
    Arduino.


    Regards, Dana.
     
  3. Константин Альфимов

    Thread Starter New Member

    Apr 1, 2019
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    Where do you see the PWM driver on display?
    This display need voltage IForvard 53 volt. (at -30 degrees) For this, I think need to install a driver MC34844. The display needs a constant current, so I think the PWM will not work.
    It may be possible to extract the brightness signal from the AUX channel and transmit via i2c to MC34844? True, I did not find such microcircuits.
    PS Motherboard changed to IB916AF-7600.
     
  4. danadak

    Distinguished Member

    Mar 10, 2018
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    I must have been looking at the wrong datasheet. Now I see it has
    no internal driver for the LED B/L.

    So you would add a PWM to do the brightness control. The 34844 has
    a PWM input.

    Regards, Dana.
     
  5. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    An LED is a current driven device. It can be dimmed with PWM.

    Have you contacted manufacturers of the display to see if they can answer your question?

    Actually, we don’t necessarily need to know your display. What we need is the identification of the display driver you’re using. So... what is it?
     
  6. Константин Альфимов

    Thread Starter New Member

    Apr 1, 2019
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    I want use MC34844 driver
     
  7. djsfantasi

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    Apr 11, 2010
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    Is that chip mounted on a complete display driver or are you creating your own driver using that chip? Are you connecting it to a micro controller? It appears that registers within the MC34844 are written with I2C. I don’t know, but suspect that you change the PWM frequency in the registers.

    Have you read the datasheet?
     
  8. Константин Альфимов

    Thread Starter New Member

    Apr 1, 2019
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    I thin Use motherboard(SMbus) --> (i2c) MCU -- Driver MC34844...
     
  9. Константин Альфимов

    Thread Starter New Member

    Apr 1, 2019
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    I thin Use motherboard(SMbus) --> (i2c) MCU -- Driver MC34844...
     
  10. djsfantasi

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    Apr 11, 2010
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    One manufacturer has responded to my inquiry. They’re in Germany, but have provided a US source that may be able to help more.

    Here is their response
    By studying the design of these modules, you may be able to answer your question.
     
  11. danadak

    Distinguished Member

    Mar 10, 2018
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    Really all you need to do is generate PWM input signal for
    34844. Board chipset must have a PWM capability in it, you
    would have to write a driver or modifiy the exisiting one, or
    use a UART or other protocol and separate low end micro
    board with PWM, and Python API to make it windows ready.

    You could even do it with lowend PIC or ATTINY or PSOC 4......

    upload_2019-4-15_21-42-47.png


    Regards, Dana.
     
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