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Asked: 2026-05-29T04:24:21+00:00

I am trying to accomplish a simple PWM generation using delays on an AVR

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I am trying to accomplish a simple PWM generation using delays on an AVR ATMega16

What i am trying to do is simply fade a led from 100% to 0% duty cycle, and later i will expand it to control two colors of a bicolor led to have a nice effect.

I have done this in mikroC with PICs before, but somehow it’s not as easy in avr-gcc, or maybe i am missing something.

My problem here is that i want the led to fade completely in 3 seconds, but i feel its fading faster. I also think that it’s spending more time on high duty cycles than on low ones. I mean that i see the led bright for a bit, then it fades, but when it becomes dim it moves to different duty cycles very fast or so i think..

Any ideas you might have on what i am missing ?

Code is available here : http://ideone.com/lUP5f

Thanks

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1 Answer

  1. Editorial Team

    It may be a problem with the fuse settings. The clock is usually controlled by fuses not by the define. However the delay function uses the #define F_CPU. Can you post your fuse settings?

    Is there a specific reason that you want to use delay instead of a timer to generate the PWM? In case you want to have a look at timers I can recommend these Tutorials to you:1)Timer Tutorial 2)PWM

    Edit: btw

     uint8_t b = 1000;

    uint8_t allows values from 0 to 255 the compiler usually generates a warning for this:

    ../test.c:16: warning: large integer implicitly truncated to unsigned type

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