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Altera_Forum's avatar
Altera_Forum
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11 years ago

Altera FPGA DE0 PWM LEDS

Hello everyone,

I want to make PWM LEDS, i mean that pwm signal will control the intensity/brightness of the leds, such as this video: https://www.youtube.com/watch?v=83benzyirnq

But how it could be possible when we have only '1' state which is 100% of brightness and '0' state which is 0% of brightness..?

With pwm I can only change the frequency of the led but not the brightness, am i right?

By the way I use FPGA Altera DE0 and i want to implement it in VHDL.

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    11 years ago

    Well PWM is the way to control the brightness. Basically you are flickering the LED on and off very fast; depending on the duty cycle the LED will appear to be brighter (long duty cycle) or dimmer (short duty cycle). 0% duty cycle = off, 100% duty cycle = always on = maximal brightness. Just pick a fast frequency to fool the eyes to not see flicker, but not too fast to allow for the LED to fully turn on - so like 1kHz would be ok.