analogWrite() not implemented

[vshymanskyy]

[me-no-dev]

will be when the driver is ready

[me-no-dev]

two types of analogWrite are now implemented through SigmaDelta and LEDC.
Headers for the relevant drivers are here and here

[jandolina]

Just found some examples!
AnalogOut

The led stuff worked for me.

[jonnor]

Will you provide an Arduino-compatible analogWrite based on one of these functions? Really convenient for compatibility with existing code examples

[Mendes11]

Is there any news about this? It's labed as 'to be implemented' but what is the priority of this? It would really helpful to have this function so it can be compatible with some libs that use it.

[vseven]

Just tried to move some code over from a ESP8266 to my shiny new ESP32 and had the same issue with analogWrite not being implemented. Will this be fixed any time soon?

[monteslu]

any update? Just hit this problem as well

[vseven]

There are work arounds using ledC. I uploaded a example into the GitHub repo:

https://github.com/espressif/arduino-esp32/blob/master/libraries/ESP32/examples/AnalogOut/ledcWrite_RGB/ledcWrite_RGB.ino

You attached a pin to ledc, set it up, then you can call commands with ledc to update the output.

[Sod-Almighty]

Over two years, and no fix? Seriously?

[stickbreaker]

@Sod-Almighty different hardware. a direct equivalent implementation is impossible. There are other methods to achieve the same functionality, but they are not exactly compatible.

You have to adjust your code to use either SigmaDelta or LEDC. Both work but they are not drop in. You as the programmer have to decide how to handle the differences.

Chuck.

[vseven]

As posted see my example. If you are programming for both say both a ESP8266 and a ESP32 you can use some if then statements to determine which to use. For example a RGB LED strip control program I have attaches the pin to use in the setup:

		#if defined(ARDUINO_ARCH_ESP32)
			ledcAttachPin(m_nPinR, m_nChannelR);
  			ledcSetup(m_nChannelR, 5000, 8);
		#else
			pinMode(m_nPinR, OUTPUT);
		#endif

Then when I need to write to the output:

		#if defined(ARDUINO_ARCH_ESP32)
			ledcWrite(m_nChannelR, subStringR);
		#else
			analogWrite(m_nPinR, subStringR);
		#endif

Although I will disagree with @stickbreaker - nothing is impossible. There has to be a way to add a wrapper for analogWrite that just does the LedC stuff for you but it doesn't look like that's going to happen.

[stickbreaker]

@vseven so,
If I use your defines, I can get a 490hz pwm signal on 4 different pins, each one with a different 8bit duration? (Arduino Uno 3, 9, 10, and 11) and a 980hz PWM signal on 2 different pins (Arduino Uno 5,6) Also with different duration's?

I do not see how the following Arduino Uno commands analogWrite(3,25); analogWrite(5,26); could be directly translated.

To directly translate from analogWrite() to ledcWrite() every interaction of of the Arduino timers would have to be emulated:

TCCR2B = (TCCR2B & 0b11111000) | 6;

I have only used analog Write for one motor controller; a brushed 8 Amp gear motor. I had to adjust the PWM freq way down before the motor could operate. So I reconfigured the base PWM to 122hz with this TCCR2B value. This allowed me to use analogWrite(3,x) to successfully operate this motor. But, I cannot expect this same command to set the ESP32's pin 3 PWM freq to 122hz.

I believe that making a partial translation would be more of a hindrance than benefit.

I know that the ESP32 is different, so to successfully set a PWM freq to 122hz I must Learn how to configure the ESP32 to achieve this goal.

Chuck.