[Solved] Increasing PWM frequency and resolution

Projects Programming
4

Here's a problem. Other things aside:

void analogWrite(uint8_t pin, int val)
{
	// We need to make sure the PWM output is enabled for those pins
	// that support it, as we turn it off when digitally reading or
	// writing with them.  Also, make sure the pin is in output mode
	// for consistenty with Wiring, which doesn't require a pinMode
	// call for the analog output pins.
	pinMode(pin, OUTPUT);
	if (val == 0)
	{
		digitalWrite(pin, LOW);
	}
	else if (val == 255)
	{
		digitalWrite(pin, HIGH);
	}
	else
	{

First, analogWrite takes a 16-bit value. So far so good. But it has a specific test for 255. That's not so good. My testing confirms that if you try something like this:

analogWrite (9, 254);
analogWrite (9, 255);   // fully on
analogWrite (9, 256);

Then you get the glitch on exactly 255. And that was after adding:

TCCR1A = 0x03;

This seems to work better:

  OCR1A = timerVal; // set pwm duty

Further testing under way ...