pwm.hpp File Reference

Simple PWM output wrapper with period and duty cycle configuration. More...

#include <cstdint>
#include "non_copyable.hpp"

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Classes
class	c7222::PwmOut
	Output-only PWM wrapper with period and duty configuration. More...
struct	c7222::PwmOut::Config
	Configuration structure for PWM output setup. More...

Namespaces
namespace	c7222
	C7222 course abstractions namespace.

Detailed Description

Simple PWM output wrapper with period and duty cycle configuration.

This class provides a minimal PWM interface focused on:

• Period (microseconds)
• Duty cycle (0.0 to 1.0)

Platform-specific behavior (Pico):

• The Pico backend configures the PWM slice/channel associated with the given GPIO and computes TOP + divider from the requested period.
• Ownership is enforced per GPIO pin. Constructing two PwmOut objects for the same pin asserts in debug builds.
• When PWM is disabled (via Enable(false)), the pin function is returned to GPIO_FUNC_SIO so it can be used as a normal GPIO again.
• When the object is destroyed, the pin is also returned to GPIO_FUNC_SIO and ownership is released.

Edge cases and usage notes:

• A GPIO cannot be driven by PWM and normal GPIO (e.g., Led) at the same time. To switch from PWM to LED control, call Enable(false) (or destroy the PwmOut) before constructing a Led on the same pin.
• If you re-enable PWM after using the pin as GPIO, call Enable(true) or Configure(...) to reapply the PWM configuration.

Example: basic PWM output

c7222::PwmOut pwm(15);
pwm.SetPeriodUs(1000.0f);   // 1 kHz
pwm.SetDutyCycle(0.25f);    // 25%
pwm.SetActiveLow(false);

Example: release PWM and reconfigure LED on same pin

c7222::PwmOut pwm(20, {20, 2000.0f, 0.5f, true, true});
pwm.Enable(false);          // return pin to GPIO
 
c7222::Led led(20);
led.Reconfigure(true, c7222::GpioDriveStrength::mA4, true);