Samplecode for Software PWM

[corado]

Hallo,
have anyone samplecode how I can make a Software PWM?
I have used the wrong Pins from Attiny 45 and now I have 200!! of wrong Boards

[stefkpl]

Hi, I don't have any code sorry but I think you must use timer interrupt with 2 variables, "_up" et "_down"

duty cycle is equal to 50% when "_up" = "_down".

Code: Select all

procedure on_Interrupt
begin
   inc(global_counter)

   if (global_counter > _up) then
   Begin
       global_counter = 0
       portx.x = 0 
   end

   if (global_counter > _down) then
   Begin
       global_counter = 0
       portx.x = 1 
   end
end

It's just little algorithm

Regards

Stéf

[jpc]

corado, what frequency and resolution do you need?

[corado]

first, I only want the rpinziple of an PWM Routinge..
I want it to use like Softpwm:=50;
Or nearly this was..

I want to use it to generate negative Voltage with coil, Diode, and Resistor at any Portpin from AVR

[jpc]

for that purpose you would want a rather high frequency , the highest frequency you could get would be a fixed 50% dutycyle driven by timerinterrupt. The interrupt_frequency in that case is only twice the pulse frequency, probably limited to a few kHz.
All you have to do in the interrupt is toggle the pin. ( keep in mind this is NOT pwm)