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Controlling LED Brightness using PWM

Nichol Lim
Prodigy 60 points

How do i control the LED brightness using PWM? I am new to tiva and i am wondering how do i have to use timers and interrupts to control the LED brightness :) I am using the TM4C123G by the way.

  • 0
    TI__Guru**** 244380 points

    Hello Nichol,

    The TM4C123G has a PWM module which can be used to generate a PWM output. What is the Frequency that you are looking for the PWM output, what is the max brightness ON time and min brightness ON time that you are looking for?

    Regards

    Amit

  • 0 in reply to Amit Ashara
    Prodigy 60 points

    Err i am using a  PWM frequency of 50Hz since the that is the minimum frequency such that the LED would not be seen as blinking when adjusting the brightness. The maximum brightness ON time and minimum brightness ON time can be forever until i disconnect the the power supply. If possible, may i know how can i adjust the brightness of the LED (one color only) by using the SW1 and SW2 buttons?

  • 0 in reply to Nichol Lim
    TI__Guru**** 244380 points

    Hello Nichol,

    1. For controlling the PWM as I mentioned there is the PWM module. There is an example code in the TIVAWare C:\ti\TivaWare_C_Series-2.1.0.12573\examples\peripherals\pwm\reload_interrupt.c that you can use as reference

    2. You can use SW1 (increase) and SW2(decrease), by setting up the GPIO's connected to them for Falling Edge Interrupt.When the Interrupt is asserted you can load the new PWM On Time value based on whether SW1 or SW2 is pressed (by adding or subtracting the required time).

    Regards

    Amit

  • 0 in reply to Amit Ashara
    Prodigy 60 points

    Okay ! I shall look into it. Thanks Amit! I appreciate your help and fast response :)