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port.rs
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port.rs
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//! Digital IO implementations for the `PORT#` peripherals
//!
//! Please take a look at the documentation for [`Pin`] for a detailed explanation.
use core::marker::PhantomData;
pub trait PinMode: crate::Sealed {}
pub mod mode {
use core::marker::PhantomData;
pub trait Io: crate::Sealed + super::PinMode {}
pub struct Output;
impl super::PinMode for Output {}
impl Io for Output {}
impl crate::Sealed for Output {}
pub trait InputMode: crate::Sealed {}
pub struct Input<IMODE> {
pub(crate) _imode: PhantomData<IMODE>,
}
impl<IMODE: InputMode> super::PinMode for Input<IMODE> {}
impl<IMODE: InputMode> Io for Input<IMODE> {}
impl<IMODE: InputMode> crate::Sealed for Input<IMODE> {}
pub struct Floating;
impl InputMode for Floating {}
impl crate::Sealed for Floating {}
pub struct PullUp;
impl InputMode for PullUp {}
impl crate::Sealed for PullUp {}
}
pub trait PinOps {
type Dynamic;
fn into_dynamic(self) -> Self::Dynamic;
unsafe fn out_set(&mut self);
unsafe fn out_clear(&mut self);
unsafe fn out_toggle(&mut self);
unsafe fn out_get(&self) -> bool;
unsafe fn in_get(&self) -> bool;
unsafe fn make_output(&mut self);
unsafe fn make_input(&mut self, pull_up: bool);
}
/// Representation of an MCU pin.
///
/// # Design Rationale
/// We want individual types per pin to model constraints which depend on a specific pin. For
/// example, some peripherals are internally hard-wired to certain pins of the MCU.
///
/// Additionally, the mode of a pin should also be a part of the type to model enforcement of pins
/// being in a certain mode and preventing misuse like for example calling `set_high()` on a pin
/// configured as input.
///
/// To do this, the [`Pin`] type is generic over the `MODE` (input, output, ...) and the `PIN`
/// (pd0, pb5, pc6, ...).
///
/// Of course, in some applications one does not care about the specific pin used. For these
/// situations, the specific pin types can be "downgraded" into a dynamic type that can represent
/// any pin. See [Downgrading](#downgrading) for more details.
///
/// # Instantiation
/// The `Peripherals` struct in HAL and board-support crates usually contains a `.pins` field which
/// is of type `Pins`. This `Pins` struct in turn has fields for each individual pin, in its
/// default mode. You can then move the pin out of this struct to reconfigure it (examples in this
/// documentation are for `atmega-hal`):
///
/// ```ignore
/// use atmega_hal::port::{Pin, mode, self};
///
/// let dp = atmega_hal::Peripherals::take().unwrap();
///
/// let output: Pin<mode::Output, port::PD3> = dp.pins.pd3.into_output();
/// ```
pub struct Pin<MODE, PIN> {
pub(crate) pin: PIN,
pub(crate) _mode: PhantomData<MODE>,
}
impl<PIN: PinOps> Pin<mode::Input<mode::Floating>, PIN> {
#[doc(hidden)]
pub fn new(pin: PIN) -> Self {
Pin {
pin,
_mode: PhantomData,
}
}
}
/// # Configuration
/// To change the mode of a pin, use one of the following conversion functions. They consume the
/// original [`Pin`] and return one with the desired mode. Only when a pin is in the correct mode,
/// does it have the mode-relevant methods availailable (e.g. `set_high()` is only available for
/// `Output` pins).
impl<PIN: PinOps, MODE: mode::Io> Pin<MODE, PIN> {
/// Convert this pin into an output pin. See [Digital Output](#digital-output).
pub fn into_output(mut self) -> Pin<mode::Output, PIN> {
unsafe { self.pin.make_output() };
Pin {
pin: self.pin,
_mode: PhantomData,
}
}
/// Convert this pin into a floating input pin. See [Digital Input](#digital-input).
///
/// *Note*: To read deterministic values from the pin, it must be externally pulled to a
/// defined level (either VCC or GND).
pub fn into_floating_input(mut self) -> Pin<mode::Input<mode::Floating>, PIN> {
unsafe { self.pin.make_input(false) };
Pin {
pin: self.pin,
_mode: PhantomData,
}
}
/// Convert this pin into a pulled-up input pin. See [Digital Input](#digital-input).
///
/// With no external circuit pulling the pin low, it will be read high.
pub fn into_pull_up_input(mut self) -> Pin<mode::Input<mode::PullUp>, PIN> {
unsafe { self.pin.make_input(true) };
Pin {
pin: self.pin,
_mode: PhantomData,
}
}
}
/// # Downgrading
/// For applications where the exact pin is irrelevant, a specific pin can be downgraded to a
/// "dynamic pin" which can represent any pin:
///
/// ```ignore
/// use atmega_hal::port::{Pin, mode};
///
/// let dp = atmega_hal::Peripherals::take().unwrap();
///
/// let any_output_pin1: Pin<mode::Output> = dp.pins.pd0.into_output().downgrade();
/// let any_output_pin2: Pin<mode::Output> = dp.pins.pd1.into_output().downgrade();
///
/// // Because they now have the same type, you can, for example, stuff them into an array:
/// let pins: [Pin<mode::Output>; 2] = [any_output_pin1, any_output_pin2];
/// ```
impl<PIN: PinOps, MODE: mode::Io> Pin<MODE, PIN> {
/// "Erase" type-level information about which specific pin is represented.
///
/// *Note*: The returned "dynamic" pin has runtime overhead compared to a specific pin.
pub fn downgrade(self) -> Pin<MODE, PIN::Dynamic> {
Pin {
pin: self.pin.into_dynamic(),
_mode: PhantomData,
}
}
}
/// # Digital Output
impl<PIN: PinOps> Pin<mode::Output, PIN> {
/// Set pin high (pull it to supply voltage).
#[inline]
pub fn set_high(&mut self) {
unsafe { self.pin.out_set() }
}
/// Set pin low (pull it to GND).
#[inline]
pub fn set_low(&mut self) {
unsafe { self.pin.out_clear() }
}
/// Toggle a high pin to low and a low pin to high.
#[inline]
pub fn toggle(&mut self) {
unsafe { self.pin.out_toggle() }
}
/// Check whether the pin is set high.
///
/// *Note*: The electrical state of the pin might differ due to external circuitry.
#[inline]
pub fn is_set_high(&self) -> bool {
unsafe { self.pin.out_get() }
}
/// Check whether the pin is set low.
///
/// *Note*: The electrical state of the pin might differ due to external circuitry.
#[inline]
pub fn is_set_low(&self) -> bool {
!unsafe { self.pin.out_get() }
}
}
/// # Digital Input
impl<PIN: PinOps, IMODE: mode::InputMode> Pin<mode::Input<IMODE>, PIN> {
/// Check whether the pin is driven high.
#[inline]
pub fn is_high(&self) -> bool {
unsafe { self.pin.in_get() }
}
/// Check whether the pin is driven low.
#[inline]
pub fn is_low(&self) -> bool {
!unsafe { self.pin.in_get() }
}
}
#[macro_export]
macro_rules! impl_port_traditional {
(
enum Ports {
$($PortName:ident: ($Port:ty, $port_port_reg:ident, $port_pin_reg:ident, $port_ddr_reg:ident),)+
}
$(#[$pins_attr:meta])*
pub struct Pins {
$($pin:ident: $Pin:ident = ($PinPort:ty, $PinPortName:ident, $pin_num:expr,
$pin_port_reg:ident, $pin_pin_reg:ident,
$pin_ddr_reg:ident),)+
}
) => {
pub use $crate::port::mode;
pub type Pin<MODE, PIN = Dynamic> = $crate::port::Pin<MODE, PIN>;
$(#[$pins_attr])*
pub struct Pins {
$(pub $pin: Pin<
mode::Input<mode::Floating>,
$Pin,
>,)+
}
impl Pins {
pub fn new(
$(_: $Port,)+
) -> Self {
Self {
$($pin: $crate::port::Pin::new(
$Pin { _private: (), }
),)+
}
}
}
#[repr(u8)]
pub enum DynamicPort {
$($PortName,)+
}
pub struct Dynamic {
port: DynamicPort,
// We'll store the mask instead of the pin number because this allows much less code to
// be generated for the trait method implementations.
mask: u8,
}
impl Dynamic {
fn new(port: DynamicPort, pin_num: u8) -> Self {
Self {
port,
mask: 1 << pin_num,
}
}
}
impl $crate::port::PinOps for Dynamic {
type Dynamic = Self;
#[inline]
fn into_dynamic(self) -> Self::Dynamic {
self
}
#[inline]
unsafe fn out_set(&mut self) {
match self.port {
$(DynamicPort::$PortName => (*<$Port>::ptr()).$port_port_reg.modify(|r, w| {
w.bits(r.bits() | self.mask)
}),)+
}
}
#[inline]
unsafe fn out_clear(&mut self) {
match self.port {
$(DynamicPort::$PortName => (*<$Port>::ptr()).$port_port_reg.modify(|r, w| {
w.bits(r.bits() & !self.mask)
}),)+
}
}
#[inline]
unsafe fn out_toggle(&mut self) {
match self.port {
$(DynamicPort::$PortName => (*<$Port>::ptr()).$port_pin_reg.modify(|r, w| {
w.bits(r.bits() | self.mask)
}),)+
}
}
#[inline]
unsafe fn out_get(&self) -> bool {
match self.port {
$(DynamicPort::$PortName => (*<$Port>::ptr()).$port_port_reg.read().bits()
& self.mask != 0,)+
}
}
#[inline]
unsafe fn in_get(&self) -> bool {
match self.port {
$(DynamicPort::$PortName => (*<$Port>::ptr()).$port_pin_reg.read().bits()
& self.mask != 0,)+
}
}
#[inline]
unsafe fn make_output(&mut self) {
match self.port {
$(DynamicPort::$PortName => (*<$Port>::ptr()).$port_ddr_reg.modify(|r, w| {
w.bits(r.bits() | self.mask)
}),)+
}
}
#[inline]
unsafe fn make_input(&mut self, pull_up: bool) {
match self.port {
$(DynamicPort::$PortName => (*<$Port>::ptr()).$port_ddr_reg.modify(|r, w| {
w.bits(r.bits() & !self.mask)
}),)+
}
if pull_up {
self.out_clear()
} else {
self.out_set()
}
}
}
$(
pub struct $Pin {
_private: ()
}
impl $crate::port::PinOps for $Pin {
type Dynamic = Dynamic;
#[inline]
fn into_dynamic(self) -> Self::Dynamic {
Dynamic::new(DynamicPort::$PinPortName, $pin_num)
}
#[inline]
unsafe fn out_set(&mut self) {
(*<$PinPort>::ptr()).$pin_port_reg.modify(|r, w| {
w.bits(r.bits() | (1 << $pin_num))
})
}
#[inline]
unsafe fn out_clear(&mut self) {
(*<$PinPort>::ptr()).$pin_port_reg.modify(|r, w| {
w.bits(r.bits() & !(1 << $pin_num))
})
}
#[inline]
unsafe fn out_toggle(&mut self) {
(*<$PinPort>::ptr()).$pin_pin_reg.modify(|r, w| {
w.bits(r.bits() | (1 << $pin_num))
})
}
#[inline]
unsafe fn out_get(&self) -> bool {
(*<$PinPort>::ptr()).$pin_port_reg.read().bits() & (1 << $pin_num) != 0
}
#[inline]
unsafe fn in_get(&self) -> bool {
(*<$PinPort>::ptr()).$pin_pin_reg.read().bits() & (1 << $pin_num) != 0
}
#[inline]
unsafe fn make_output(&mut self) {
(*<$PinPort>::ptr()).$pin_ddr_reg.modify(|r, w| {
w.bits(r.bits() | (1 << $pin_num))
})
}
#[inline]
unsafe fn make_input(&mut self, pull_up: bool) {
(*<$PinPort>::ptr()).$pin_ddr_reg.modify(|r, w| {
w.bits(r.bits() & !(1 << $pin_num))
});
if pull_up {
self.out_clear()
} else {
self.out_set()
}
}
}
)+
};
}
#[macro_export]
macro_rules! renamed_pins {
(
type Pin = $PinType:ident;
$(#[$pins_attr:meta])*
pub struct Pins from $McuPins:ty {
$($(#[$pin_attr:meta])* pub $pin:ident: $Pin:ty = $pin_orig:ident,)+
}
) => {
$(#[$pins_attr])*
pub struct Pins {
$($(#[$pin_attr])*
pub $pin: $PinType<
$crate::port::mode::Input<$crate::port::mode::Floating>,
$Pin,
>,)+
}
impl Pins {
pub fn with_mcu_pins(pins: $McuPins) -> Self {
Self {
$($pin: pins.$pin_orig,)+
}
}
}
};
}