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Function to generate Triangle wave form

Greeting all,
I'm trying to write a simulate function to generate triangle wave form to test on Keil IDE, but I could not make it. I've read the code examples in Simulation section for sine, square and saw tooth, but could not figure out how to write triangle function. Can some one spend some time to help me to go through this. I'm novice in C, so please bear with me. Any inputs will be greatly appreciated. Have a great day.

PS:
With this function I can generate saw tooth wave form but I can't change or set frequency.

signal void Adc_0 ()
{
	float volts;
	float limit;
	limit = 5.0;

 	while (1)				   /* forever */
	{
    	volts = 0;
    	while (volts < limit)
		{
     		ain0 = volts;      /* analog input-0 */
			swatch (0.0002);   /* 200us  */
			volts += 0.1;      /* increase voltage */
    	}

		volts = limit;
		while (volts > 0.0)
		{
			ain0 = volts;
			swatch (0.0002);   /* 200us  */
			volts -= 0.1;      /* decrease voltage */
		}
	}
}

Parents

0 TheLam Nguyen over 19 years ago in reply to erik malund

Dear Erik,
Thank you for your prompt reply. The code I used, primely is modified from the examples from Keil webpage. They use a lots of float variable there. By looking at the wave form, the triagle s just a little different from sine wave, and the sine wave is produced by the code below. I think I can modify the code to make triagle, but it din't work.
Here is the sine wave function from Keil:

signal void Ain_0_Sin ()
{
	float volts;        // peak-to-peak voltage
	float frequency;    // output frequency in Hz
	float offset;       // voltage offset
	float duration;     // duration in Seconds
	float val;
	long  i, end;

	volts     = 2.5;
	offset    = 2.5;
	frequency = 60;
	duration  = 0.1;

	printf ("Sine Wave Signal on AD Channel 0.\n");

	end = (duration * 1000000);
	for (i = 0 ; i < end; i++)
	{
    	val = __sin (frequency * (((float) STATES) / CLOCK) * 2 * 3.1415926);
    	ain0 = (val * volts) + offset;
//		swatch (0.00001);
    	twatch (1);                // in 10 uSec steps
	}
}

If I use

swatch (1);

as you suggested it will not produce any thing. However, if I use

twatch (1);

then it works.
This one I modified from sine wave function and it's not working:

signal void Ain_0_Tri (void)
{
	float volts;        // peak-to-peak volatage
	float frequency;    // output frequency in Hz
	float offset;       // volatge offset
	float duration;     // duration in Seconds
	float val;
	long  i, end, steps;

	volts     = 4.9;
	offset    = 0.1;
	frequency = 60;
	duration  = 0.2;

	printf ("Tri Signal on AD Channel 0.\n");

	steps = (100000 * (1/frequency));
	end = (duration * 1000000);

	for (i = 0 ; i < end; i++)
	{
		val = (i % (steps)) / (1/(2*frequency));
		ain0 = (val * volts) + offset;
		twatch (10);                // in 10 uSec steps
	}
}

Can someone helps to shed some light on my problem? Your help will be greatly appreciated.

Reply

0 TheLam Nguyen over 19 years ago in reply to erik malund

signal void Ain_0_Sin ()
{
	float volts;        // peak-to-peak voltage
	float frequency;    // output frequency in Hz
	float offset;       // voltage offset
	float duration;     // duration in Seconds
	float val;
	long  i, end;

	volts     = 2.5;
	offset    = 2.5;
	frequency = 60;
	duration  = 0.1;

	printf ("Sine Wave Signal on AD Channel 0.\n");

	end = (duration * 1000000);
	for (i = 0 ; i < end; i++)
	{
    	val = __sin (frequency * (((float) STATES) / CLOCK) * 2 * 3.1415926);
    	ain0 = (val * volts) + offset;
//		swatch (0.00001);
    	twatch (1);                // in 10 uSec steps
	}
}

If I use

swatch (1);

as you suggested it will not produce any thing. However, if I use

twatch (1);

then it works.
This one I modified from sine wave function and it's not working:

signal void Ain_0_Tri (void)
{
	float volts;        // peak-to-peak volatage
	float frequency;    // output frequency in Hz
	float offset;       // volatge offset
	float duration;     // duration in Seconds
	float val;
	long  i, end, steps;

	volts     = 4.9;
	offset    = 0.1;
	frequency = 60;
	duration  = 0.2;

	printf ("Tri Signal on AD Channel 0.\n");

	steps = (100000 * (1/frequency));
	end = (duration * 1000000);

	for (i = 0 ; i < end; i++)
	{
		val = (i % (steps)) / (1/(2*frequency));
		ain0 = (val * volts) + offset;
		twatch (10);                // in 10 uSec steps
	}
}

Can someone helps to shed some light on my problem? Your help will be greatly appreciated.

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