help me, something wrong with my output (pwm arduino)

[haneys]

Hi.. I need help.. i have the coding as shown below, but its not working as what i expected.. base on what i know, the coding below should provide me a 2MHz frecuency at output pin 9 and 1kHz at ouput pin 8.. but when i test it with oscilloscope i only obtain 2kHz at output pin 9.. what should i do to obtain 2MHz at output pin 9?? how can i change/modified the code?? many2 thankz..

Code: Select all

#include <util/delay.h>
int rog = 8;
void setup() {
  pinMode(9, OUTPUT);
  pinMode(rog, OUTPUT);
 
  TCCR1A = 0;
  TCCR1B = 0;
 
  TCCR1A |= _BV(WGM11) | _BV(COM1A1);
  TCCR1B |= _BV(WGM12) | _BV(WGM13) | _BV(CS10) | _BV(ICNC1);

  ICR1= 7;

  OCR1A = 3;
}

void loop(){
delayrog();

}

void delayrog(){
   while (1)
   {
      
  digitalWrite(rog, HIGH);
  _delay_ms(0.52);
  digitalWrite(rog, LOW);
  _delay_ms(0.52);
 
   }
}

[adafruit_support_rick]

Looks right to me. I'm getting 2MHZ from your code on a Uno

What processor are you running? Are you sure your CPU is running at 16MHz?

Are you sure you're reading your scope correctly?

[haneys]

really? then how can i make sure i run my cpu at 16MHz?
i can get 2Mz at output pin 9 when i only use the first code below, but when i add up another output at pin 8 i wont get 2Mz at output pin 9.. i found this weird.. help me..

without output at pin 8:

Code: Select all

void setup() {
  pinMode(9, OUTPUT);
 
  TCCR1A = 0;
  TCCR1B = 0;
 
  TCCR1A |= _BV(WGM11) | _BV(COM1A1);
  TCCR1B |= _BV(WGM12) | _BV(WGM13) | _BV(CS10) | _BV(ICNC1);

  ICR1= 7;

  OCR1A = 3;
}

void loop(){

}

having output at pin 8:

Code: Select all

#include <util/delay.h>
int rog = 8;
void setup() {
  pinMode(9, OUTPUT);
  pinMode(rog, OUTPUT);
 
  TCCR1A = 0;
  TCCR1B = 0;
 
  TCCR1A |= _BV(WGM11) | _BV(COM1A1);
  TCCR1B |= _BV(WGM12) | _BV(WGM13) | _BV(CS10) | _BV(ICNC1);

  ICR1= 7;

  OCR1A = 3;
}

void loop(){
delayrog();

}

void delayrog(){
   while (1)
   {
     
  digitalWrite(rog, HIGH);
  _delay_ms(0.52);
  digitalWrite(rog, LOW);
  _delay_ms(0.52);
 
   }
}

[pburgess]

Perhaps DigitalWrite() is playing dirty pool with the PORT/PIN registers. Try using direct PORT manipulation and see if that helps: tutorial on Arduino.cc site.

[haneys]

Did u mean like this? still wont work..

Code: Select all

#include <avr/io.h>
#define F_CPU 16000000UL //set 16mhz crystal
#include <util/delay.h>
int rog = 8;
float rogdelay = 0.6;
void setup() {
  pinMode(9, OUTPUT);
TCCR1A = 0;
  TCCR1B = 0;
 
  TCCR1A |= _BV(WGM11) | _BV(COM1A1);
  TCCR1B |= _BV(WGM12) | _BV(WGM13) | _BV(CS10) | _BV(ICNC1);

  ICR1= 7;

  OCR1A = 3;
//  OCR2B = 3;
}

void loop(){
delayrog();

}
DDRB |=0b00001010; //set pin mana jadi output
   PORTB = 0b00000000;
               PORTB = 0b00000001 ;
      _delay_ms(0.52);
      PORTB = 0b00000000 ;
      _delay_ms(0.52);
   }
}


[adafruit_support_rick]

I think it's more likely that _delay_ms is doing something with the timer. None of the standard arduino library implementations seem to use any timers, but maybe you've got some other toolchain?

As I said, I ran the exact code you posted on a Uno with Arduino 1.0.1, and I'm getting 2MHz on Pin 9. I'm getting about 947Hz on pin 8.

BTW - you don't need to set _BV(ICNC1) in TCCRB1, since you're not using input capture. Anyway, input capture is disabled when you set pin 9 to output.