How to use output PWM in AVR

Question

I have this code to blink an array (8-led) of led one after one:

#include <avr/io.h>
#include <avr/delay.h>
#define dela 500
int main (void)
{
 DDRC = 0xFF;
 for(int i=0; ; i++,i%=8)
 {
 PORTC |=(1<<i);
 delay_ms(dela);
 PORTC &= ~(1 << i);
 delay_ms(dela);
 }
}

I want to light up those led partially, like dimmed version of this, something like PWM

Now my question is how can I do that, how can I write analog output ?

Micro-controller : ATmega8A - PDIP

• jsotola: you would require a DAC for analog output ... that is different from PWM ... an analog output is not necessary for varying the brightness of an LED ... a PWM signal is preferrable because it does not involve analog voltage levels
• Caleb Reister: Have you considered using larger resistors? You only need one resistor since there will only be one running at a time.
• Caleb Reister: If you want to minimize software overhead, I would recommend getting a 3-to-8 decoder like the 74HC138 and connecting the PWM out to one of the enable lines. This would require only four pins and greatly reduce software overhead.
• Maifee Ul Asad: PWM is solved , I just need how can I write analogWrite() like thing in avr as in arduino

Answer 1

Modulate the LED "on" time.

Something like this.

for(int i=0; ; i++,i%=8)
{
 for(int k=0; k<26; k++)
 {
 PORTC |=(1<<i);
 delay_ms(10);
 PORTC &= ~(1 << i);
 delay_ms(10);
 }
 delay_ms(dela);
}

• Maifee Ul Asad: I couldn't find any usage of k, What i want is like instead of output true of false, setting or resetting,0 volt or 5 volt. I want to write an analog output.
• jsotola: what does this mean? ... I couldn't find any usage of k
• Maifee Ul Asad: You are using k in the loop and iterating 25 times. And then using the old code, no usage of k. So will it actually dim the light? I haven't tested yet.
• Maifee Ul Asad: Now I have got it after testing it.. Can you edit the answer and help me with the analogWrite() type thing
• jsotola: that is a different question ... post another question