Week 14 Audio Recording and Play Back

Task 1: The LPF Output

Feeding a modified PWM signal into a low-pass filter (LPF) can produce an arbitrary analog output signal.

 

What is the calculated corner frequency of our (2nd order) low pass filter?



Frequency response?





PE3 is the OC3A pin, it is the PWM Module 3A.



ICRn defines the top, OCRnx defines the duty value.



Let's still pick up the non-inverting mode. We are using module A so to turn this mode one, we need the following line:
TCCR3A |= (1 << COM3A1);





To identify JP6 and JP5:



The OPA344 Op Amp SOT23 package.



Both jumpers need to be installed on your Skyboard for this task.





Code for Task 1

Demo video: