The main user-facing module: a GenServer that manages a single PWM output and caches its state.

By default it talks to the application-supervised Pwmx.Backend. Pass a :backend option to bind it to a specific backend instance instead, this is how you drive an isolated virtual board in tests:

{:ok, backend} = Pwmx.Backend.start_link(name: :my_board, mode: :virtual)
{:ok, pid} = Pwmx.Output.start_link({"virtualchip0", 1}, backend: backend)

The setters cache the value they write rather than reading it back from the backend, the achievable value by the driver can differ. Call get_period/1 or get_duty_cycle/1 to re-read if you need the actual timing.