31khz PWM on TIMER2 atmega8

Using Arduino Programming Questions
#1

Hey,
I have been trying to generate a 31khz variable duty cycle pwm on atmega8. So far I have been able to generate 7 different frequency pwm with Fast pwm and 16mhz external crystal.

TCCR2_explained
TCCR2_explained1386×757 108 KB

But I cant seem to generate 31khz variable duty cycle one.

I can use ctc mode but its toogle only.

Any help will be appreciated :slight_smile:

#2

Post the code, using code tags, and explain the problem with it.

#3 
void setup() {
  pinMode(11, OUTPUT);
  TCCR2=0x6A; //01101010 in hex
  OCR2=0x80; //128 in hex

}

void loop() {

}

This gives me a 7.8khz 50% pwm on pin 11. What I am trying to achieve a 31khz pwm with variable duty cycle.

I am using minicore at here for compilation for atmega8

#4

The clock select bits you have chosen for TCCR2 divide the system clock by 8. Choose TCCR2= 0x68 to divide by 1, for 62.5 kHz PWM.

For intermediate values you need to use a different TOP than 256, with a decrease in PWM resolution.