Module pin

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§Type-level module for GPIO pins

This module provides a type-level API for GPIO pins. It uses the type system to track the state of pins at compile-time. Representing GPIO pins in this manner incurs no run-time overhead. Each Pin struct is zero-sized, so there is no data to copy around. Instead, real code is generated as a side effect of type transformations, and the resulting assembly is nearly identical to the equivalent, hand-written C.

To track the state of pins at compile-time, this module uses traits to represent type classes and types as instances of those type classes. For example, the trait InputConfig acts as a type-level enum of the available input configurations, and the types Floating, PullDown and PullUp are its type-level variants.

Type-level Pins are parameterized by two type-level enums, PinId and PinMode.

pub struct Pin<I, M>
where
    I: PinId,
    M: PinMode,
{
    // ...
}

A PinId identifies a pin by it’s group (A, B, C or D) and pin number. Each PinId instance is named according to its datasheet identifier, e.g. PA02.

A PinMode represents the various pin modes. The available PinMode variants are Disabled, Input, Interrupt, Output and Alternate, each with its own corresponding configurations.

It is not possible for users to create new instances of a Pin. Singleton instances of each pin are made available to users through the Pins struct.

To create the Pins struct, users must supply the PAC Port peripheral. The Pins struct takes ownership of the Port and provides the corresponding pins. Each Pin within the Pins struct can be moved out and used individually.

let mut peripherals = Peripherals::take().unwrap();
let pins = Pins::new(peripherals.Port);

Pins can be converted between modes using several different methods.

// Use one of the literal function names
let pa27 = pins.pa27.into_floating_input();
// Use a generic method and one of the `PinMode` variant types
let pa27 = pins.pa27.into_mode::<FloatingInput>();
// Specify the target type and use `From`/`Into`
let pa27: Pin<PA27, FloatingInput> = pins.pa27.into();

§Embedded HAL traits

This module implements all of the embedded HAL GPIO traits for each Pin in the corresponding PinModes, namely: InputPin, OutputPin, ToggleableOutputPin and StatefulOutputPin.

For example, you can control the logic level of an OutputPin like so

use atsamd_hal::pac::Peripherals;
use atsamd_hal::gpio::Pins;
use crate::ehal_02::digital::v2::OutputPin;

let mut peripherals = Peripherals::take().unwrap();
let mut pins = Pins::new(peripherals.Port);
pins.pa27.set_high();

§Type-level features

This module also provides additional, type-level tools to work with GPIO pins.

The OptionalPinId and OptionalPin traits use the OptionalKind pattern to act as type-level versions of Option for PinId and Pin respectively. And the AnyPin trait defines an AnyKind type class for all Pin types.

Structs§

Alternate: Type-level variant of PinMode for alternate peripheral functions
Disabled: Type-level variant of PinMode for disabled modes
Input: Type-level variant of PinMode for input modes
Interrupt: Type-level variant of PinMode for Interrupt modes
Output: Type-level variant of PinMode for output modes
Pin: A type-level GPIO pin, parameterized by PinId and PinMode types
Pins: Collection of all the individual Pins

Enums§

B: Type-level variant of AlternateConfig for alternate peripheral function B
C: Type-level variant of AlternateConfig for alternate peripheral function C
D: Type-level variant of AlternateConfig for alternate peripheral function D
E: Type-level variant of AlternateConfig for alternate peripheral function E
F: Type-level variant of AlternateConfig for alternate peripheral function F
Floating: Type-level variant of both DisabledConfig and InputConfig
G: Type-level variant of AlternateConfig for alternate peripheral function G
H: Type-level variant of AlternateConfig for alternate peripheral function H
PA00: Pin ID representing pin PA00
PA01: Pin ID representing pin PA01
PA02: Pin ID representing pin PA02
PA03: Pin ID representing pin PA03
PA04: Pin ID representing pin PA04
PA05: Pin ID representing pin PA05
PA06: Pin ID representing pin PA06
PA07: Pin ID representing pin PA07
PA08: Pin ID representing pin PA08
PA09: Pin ID representing pin PA09
PA10: Pin ID representing pin PA10
PA11: Pin ID representing pin PA11
PA12: Pin ID representing pin PA12
PA13: Pin ID representing pin PA13
PA14: Pin ID representing pin PA14
PA15: Pin ID representing pin PA15
PA16: Pin ID representing pin PA16
PA17: Pin ID representing pin PA17
PA18: Pin ID representing pin PA18
PA19: Pin ID representing pin PA19
PA20: Pin ID representing pin PA20
PA21: Pin ID representing pin PA21
PA22: Pin ID representing pin PA22
PA23: Pin ID representing pin PA23
PA24: Pin ID representing pin PA24
PA25: Pin ID representing pin PA25
PA27: Pin ID representing pin PA27
PA28: Pin ID representing pin PA28
PA30: Pin ID representing pin PA30
PA31: Pin ID representing pin PA31
PB02: Pin ID representing pin PB02
PB03: Pin ID representing pin PB03
PB08: Pin ID representing pin PB08
PB09: Pin ID representing pin PB09
PB10: Pin ID representing pin PB10
PB11: Pin ID representing pin PB11
PB22: Pin ID representing pin PB22
PB23: Pin ID representing pin PB23
PullDown: Type-level variant of both DisabledConfig and InputConfig
PullUp: Type-level variant of both DisabledConfig and InputConfig
PushPull: Type-level variant of OutputConfig for a push-pull configuration
Readable: Type-level variant of OutputConfig for a readable push-pull configuration

Traits§

AlternateConfig: Type-level enum for alternate peripheral function configurations
AnyPin: Type class for Pin types
DisabledConfig: Type-level enum for disabled configurations
InputConfig: Type-level enum for input configurations
InterruptConfig: Type-level enum for Interrupt configurations
OptionalPin: Type-level equivalent of Option<PinId>
OptionalPinId: Type-level equivalent of Option<PinId>
OutputConfig: Type-level enum for output configurations
PinId: Type-level enum for pin IDs
PinMode: Type-level enum representing pin modes
SomePin: Type-level equivalent of Some(PinId)
SomePinId: Type-level equivalent of Some(PinId)

Type Aliases§

AlternateB: Type-level variant of PinMode for alternate peripheral function B
AlternateC: Type-level variant of PinMode for alternate peripheral function C
AlternateD: Type-level variant of PinMode for alternate peripheral function D
AlternateE: Type-level variant of PinMode for alternate peripheral function E
AlternateF: Type-level variant of PinMode for alternate peripheral function F
AlternateG: Type-level variant of PinMode for alternate peripheral function G
AlternateH: Type-level variant of PinMode for alternate peripheral function H
FloatingDisabled: Type-level variant of PinMode for floating disabled mode
FloatingInput: Type-level variant of PinMode for floating input mode
FloatingInterrupt: Type-level variant of PinMode for floating Interrupt mode
PullDownDisabled: Type-level variant of PinMode for pull-down disabled mode
PullDownInput: Type-level variant of PinMode for pull-down input mode
PullDownInterrupt: Type-level variant of PinMode for pull-down Interrupt mode
PullUpDisabled: Type-level variant of PinMode for pull-up disabled mode
PullUpInput: Type-level variant of PinMode for pull-up input mode
PullUpInterrupt: Type-level variant of PinMode for pull-up Interrupt mode
PushPullOutput: Type-level variant of PinMode for push-pull output mode
ReadableOutput: Type-level variant of PinMode for readable push-pull output mode
Reset: Type alias for the PinMode at reset
SpecificPin: Type alias to recover the specific Pin type from an implementation of AnyPin

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