#[entry]
fn main() -> ! {
let p = Peripherals::take().unwrap();
let gpio0 = p0::Parts::new(p.P0);
let pin: P0_01<Disconnected> = gpio0.p0_01;
// let gpio0_01_again = gpio0.p0_01; // Error, moved.
let pin_input: P0_01<Input<Floating>> = pin.into_floating_input();
if pin_input.is_high().unwrap() {
// ...
}
let mut pin_output: P0_01<Output<OpenDrain>> = pin_input
.into_open_drain_output(OpenDrainConfig::Disconnect0Standard1, Level::Low);
pin_output.set_high().unwrap();
// pin_input.is_high(); // Error, moved.
let _pin2: P0_02<Output<OpenDrain>> = gpio0
.p0_02
.into_open_drain_output(OpenDrainConfig::Disconnect0Standard1, Level::Low);
let _pin3: P0_03<Output<PushPull>> = gpio0.p0_03.into_push_pull_output(Level::Low);
loop {}
}
Pins don’t implement Copy or Clone, so only one instance of each can exist. Once a pin is
moved out of the port struct nobody else can take it.
Changing the configuration of a pin consumes the old pin instance, so you can’t keep use the old
instance afterwards.
The type of a value indicates the state that it is in: e.g. in this case, the configuration state
of a GPIO pin. This encodes the state machine into the type system, and ensures that you don’t
try to use a pin in a certain way without properly configuring it first. Illegal state
transitions are caught at compile time.
You can call is_high on an input pin and set_high on an output pin, but not vice-versa.