SparkFun Forums 

Where electronics enthusiasts find answers.

Your source for all things Atmel.
By Focus_Torn
#92856
Have been lurking here for a while and think this forum is great, so I figured I would try my hand at asking for some help.

I am using an ATTINY2313, and have the ICP working fine using:
Code: Select all
#include <avr/io.h>
#include <avr/interrupt.h>

#define READ(port,pin) (PIN ## port & (1<<pin)) 
#define INPUT(port,pin) DDR ## port &= ~(1<<pin)
#define OUTPUT(port,pin) DDR ## port |= (1<<pin)
#define CLEAR(port,pin) PORT ## port &= ~(1<<pin)
#define SET(port,pin) PORT ## port |= (1<<pin)
#define TOGGLE(port,pin) PORT ## port ^= (1<<pin)

	volatile unsigned int pWidth;
	volatile unsigned int pStart;
	volatile unsigned int pStop;

int main (void)
{
	INPUT(D,6);	// Input Capture Pin set as input
	SET(D,6);	// Enable pull-up resistor

	OUTPUT(B,0);	// Declare PB0 as output

	TCCR1B = (1<<CS11);	// Set prescaler to 8
	TCCR1B |= (1<<ICES1);	// Input capture in rising edge
	TIMSK = (1<<ICIE1);	// Enable Input Capture interrupt

	pWidth = 1500;

	while(1)
	{
		sei();
		if(pWidth <= 1470)
		{
			PORTB |= (1<<PB0);
		}
		else
		{
			PORTB &= ~(1<<PB0); 
		}
	}
}

ISR(TIMER1_CAPT_vect)
{

	PORTB ^= (1<<PB0);
    pStop = ICR1;
    if (TCCR1B & (1<<ICES1))
	{
        TCCR1B &= ~(1<<ICES1);
        pStart = pStop;
    }
	else
	{
        TCCR1B |= (1<<ICES1);
        pWidth = pStop - pStart;
    } 
}
I am wondering if I am searching for the holy grail by trying to incorporate a PWM output to an LED on the same timer? Or maybe I can not wrap my head around what needs to be done.

Is this even possible? If it is, what am I looking to do?

Is the code ok for what I am wanting or am I registers that are inhibiting the PWM out?

Ending result is to have one PWM being read on Timer0, one PWM being read on the ICP and to have the ICP PWM decide what duty cycle to be used for a PWM output.

Please show me the light. :D
By bugtraker
#95163
Before we'll get to the solution, could you clarify what you're trying to do (I know about 2xPWM and timer etc.)?
For now:
- sei() should not be called all the time in while(1) loop (should be called before the loop)
- You toogle the pin in while(1) loop and then you toogle the same pin in ISR context

Please clarify.
long long title how many chars? lets see 123 ok more? yes 60

We have created lots of YouTube videos just so you can achieve [...]

Another post test yes yes yes or no, maybe ni? :-/

The best flat phpBB theme around. Period. Fine craftmanship and [...]

Do you need a super MOD? Well here it is. chew on this

All you need is right here. Content tag, SEO, listing, Pizza and spaghetti [...]

Lasagna on me this time ok? I got plenty of cash

this should be fantastic. but what about links,images, bbcodes etc etc? [...]