Teensy 3.5 - How to write data to DAC pins easily?

[mike6789]

Hi all,

I want to just output some values to the DAC pins in my loop() code.

Cannot seem to find information on how to do this.

I don't want to use the audio library.

Any help?

Thanks!

 

[KurtE]

You might try using analogWrite()...
https://www.arduino.cc/reference/en/language/functions/analog-io/analogwrite/

 

[MichaelMeissner]

Hi all,

I want to just output some values to the DAC pins in my loop() code.

Cannot seem to find information on how to do this.

I don't want to use the audio library.

Any help?

Thanks!

You use the analogWrite function. If you are writing to a DAC pin (A21/A22 on the Teensy 3.5/3.6, A14 on the Teensy 3.1/3.2, or A12 on the Teensy LC), it does a real analog write (i.e. adjusts the voltage of the pin). You might need an amplifier on the pin(s) before connecting it to a speaker.

Due to poor naming of the function from original Arduino systems, analogWrite on a digital pin that supports PWM, rapidly turns the pin on/off, so that it approximates an analog signal (if you are looking at a LED, it will appear to dim the LED, as the light turns on/off faster than the eye can see). Typically you would need a low pass filter if you want a PWM output to better approximate an analog signal.

And yes, IMHO, the original Arduino should have called the second function something like pwmWrite, but they didn't.

 

[mike6789]

You use the analogWrite function. If you are writing to a DAC pin (A21/A22 on the Teensy 3.5/3.6, A14 on the Teensy 3.1/3.2, or A12 on the Teensy LC), it does a real analog write (i.e. adjusts the voltage of the pin). You might need an amplifier on the pin(s) before connecting it to a speaker.

Due to poor naming of the function from original Arduino systems, analogWrite on a digital pin that supports PWM, rapidly turns the pin on/off, so that it approximates an analog signal (if you are looking at a LED, it will appear to dim the LED, as the light turns on/off faster than the eye can see). Typically you would need a low pass filter if you want a PWM output to better approximate an analog signal.

And yes, IMHO, the original Arduino should have called the second function something like pwmWrite, but they didn't.

Oops... duh... thanks guys!