PWM Configuration Defaults

Question

Problem: PWM Configuration Defaults. Solve this hands-on electronics task on EWskills.

Accepted Answer

#include 
using namespace std;

// Default frequency = 1000 Hz
// Default deadtime = 0 us
void setPWM(int duty, int frequency = 1000, int deadtime = 0) {
    cout << duty << " " << frequency << " " << deadtime;
}

int main() {
    int duty, mode;
    cin >> duty >> mode;

    if (mode == 0) {
        setPWM(duty);                      // use both defaults
    }
    else if (mode == 1) {
        int frequency;
        cin >> frequency;
        setPWM(duty, frequency);           // override frequency only
    }
    else if (mode == 2) {
        int frequency, deadtime;
        cin >> frequency >> deadtime;
        setPWM(duty, frequency, deadtime); // override both
    }

    return 0;
}

Explanation & Logic Summary:

Default arguments allow setPWM to be called with 1, 2, or 3 parameters using a single function definition.

The required parameter (duty) appears first, followed by optional parameters with default values.

If only duty is provided, both frequency and deadtime use defaults.
If frequency is provided, only deadtime uses its default.
If all parameters are provided, all defaults are overridden.

This enforces C++’s rule that default arguments must appear at the end of the parameter list.

Firmware Relevance & Real-World Context:

PWM drivers frequently expose optional configuration parameters such as frequency and dead-time.

In real firmware:

Basic applications may adjust only duty-cycle
Advanced applications tune frequency and dead-time for efficiency or safety

Using default arguments enables clean, scalable embedded APIs that support both simple and advanced use cases without code duplication.

This mirrors real-world motor control, LED dimming, and power electronics firmware design.

18. PWM Configuration Defaults