add dac impl copied from stm32f0xx-hal

Author: jacobrosenthal

CHANGELOG.md

@@ -18,6 +18,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Reexport PAC as `pac` for consistency with other crates, consider `stm32` virtually deprecated
 - Added external interrupt (EXTI) support for output pins
 - Added `check_interrupt` method for GPIO pins
+- Basic support for DAC
 
 ## [v0.8.3] - 2020-06-12
 

src/dac.rs

@@ -0,0 +1,97 @@
+//! # API for the Digital to Analog converter
+//!
+//! Currently only supports writing to the DR of the DAC,
+//! just a basic one-shot conversion.
+#![deny(unused_imports)]
+use core::mem;
+
+use crate::gpio::gpioa::{PA4, PA5};
+use crate::gpio::Analog;
+use crate::pac::DAC;
+use crate::stm32::RCC;
+
+pub struct C1;
+pub struct C2;
+
+pub trait DacOut<V> {
+    fn set_value(&mut self, val: V);
+    fn get_value(&mut self) -> V;
+}
+
+pub trait DacPin {
+    fn enable(&mut self);
+}
+
+pub trait Pins<DAC> {
+    type Output;
+}
+
+impl Pins<DAC> for PA4<Analog> {
+    type Output = C1;
+}
+
+impl Pins<DAC> for PA5<Analog> {
+    type Output = C2;
+}
+
+impl Pins<DAC> for (PA4<Analog>, PA5<Analog>) {
+    type Output = (C1, C2);
+}
+
+pub fn dac<PINS>(_dac: DAC, _pins: PINS) -> PINS::Output
+where
+    PINS: Pins<DAC>,
+{
+    // NOTE(unsafe) This executes only during initialisation
+    let rcc = unsafe { &(*RCC::ptr()) };
+
+    // Enable DAC clocks
+    rcc.apb1enr.modify(|_, w| w.dacen().set_bit());
+
+    // Reset DAC
+    rcc.apb1rstr.modify(|_, w| w.dacrst().set_bit());
+    rcc.apb1rstr.modify(|_, w| w.dacrst().clear_bit());
+
+    unsafe { mem::MaybeUninit::uninit().assume_init() }
+}
+
+macro_rules! dac {
+    ($CX:ident, $en:ident, $cen:ident, $cal_flag:ident, $trim:ident, $mode:ident, $dhrx:ident, $dac_dor:ident, $daccxdhr:ident) => {
+        impl DacPin for $CX {
+            fn enable(&mut self) {
+                let dac = unsafe { &(*DAC::ptr()) };
+                dac.cr.modify(|_, w| w.$en().set_bit());
+            }
+        }
+
+        impl DacOut<u16> for $CX {
+            fn set_value(&mut self, val: u16) {
+                let dac = unsafe { &(*DAC::ptr()) };
+                dac.$dhrx.write(|w| unsafe { w.bits(val as u32) });
+            }
+
+            fn get_value(&mut self) -> u16 {
+                let dac = unsafe { &(*DAC::ptr()) };
+                dac.$dac_dor.read().bits() as u16
+            }
+        }
+    };
+}
+
+pub trait DacExt {
+    fn constrain<PINS>(self, pins: PINS) -> PINS::Output
+    where
+        PINS: Pins<DAC>;
+}
+
+impl DacExt for DAC {
+    fn constrain<PINS>(self, pins: PINS) -> PINS::Output
+    where
+        PINS: Pins<DAC>,
+    {
+        dac(self, pins)
+    }
+}
+
+dac!(C1, en1, cen1, cal_flag1, otrim1, mode1, dhr12r1, dor1, dacc1dhr);
+dac!(C2, en2, cen2, cal_flag2, otrim2, mode2, dhr12r2, dor2, dacc2dhr);

src/lib.rs

@@ -87,6 +87,11 @@ pub use crate::stm32::interrupt;
 pub mod adc;
 #[cfg(feature = "device-selected")]
 pub mod bb;
+#[cfg(all(
+    feature = "device-selected",
+    not(any(feature = "stm32f411", feature = "stm32f412", feature = "stm32f401",))
+))]
+pub mod dac;
 #[cfg(feature = "device-selected")]
 pub mod delay;
 #[cfg(feature = "device-selected")]

src/prelude.rs

@@ -4,6 +4,11 @@ pub use embedded_hal::digital::v2::StatefulOutputPin as _embedded_hal_digital_v2
 pub use embedded_hal::digital::v2::ToggleableOutputPin as _embedded_hal_digital_v2_ToggleableOutputPin;
 pub use embedded_hal::prelude::*;
 
+#[cfg(all(
+    feature = "device-selected",
+    not(any(feature = "stm32f411", feature = "stm32f412", feature = "stm32f401",))
+))]
+pub use crate::dac::DacExt as _stm32f4xx_hal_dac_DacExt;
 pub use crate::gpio::GpioExt as _stm32f4xx_hal_gpio_GpioExt;
 pub use crate::i2c::Pins as _stm32f4xx_hal_i2c_Pins;
 pub use crate::rcc::RccExt as _stm32f4xx_hal_rcc_RccExt;