software pwm

[bakil]

can just somebody explain how i can calculate the period that a led needs to be off and on at lets say 3.69mhz (or use something else but mention it  )

my goal is to build a function that you give a % and then the led is burning at that %



//------------ old topic -------------\\
does anyone of you people at societyofrobots know how to make an software PWM for fading a LED

my microcontroller runs at 4khz (i think this is the most easy frequency)

-> i know its something like 1micro seconde on and 3 microseconds off etc

[Steve Joblin]

If you tell us what microcontroller you are using and what language you are programming it in, I am sure we can help you.

[bakil]

ow woops im srry

i use C

atmega16L programmed with the stk500 board

[Steve Joblin]

This was designed for PICs, but it may work for Atmegas as well... http://www.micro-examples.com/public/microex-navig/doc/097-pwm-calculator.html

[Admin]

If you have your LED off for 3us and on for 1us, that means your LED will only be 1us/(1us+3us) = 25% bright.