Add example that cycles through all power modes

Author: hannobraun

examples/pwr.rs

@@ -0,0 +1,158 @@
+#![no_main]
+#![no_std]
+
+
+extern crate panic_halt;
+
+
+use cortex_m::asm;
+use cortex_m_rt::entry;
+use stm32l0xx_hal::{
+    prelude::*,
+    exti,
+    gpio::{
+        self,
+        Output,
+        PushPull,
+        gpiob::PB,
+    },
+    pac,
+    pwr::{
+        self,
+        PWR,
+    },
+    rcc,
+    rtc::{
+        self,
+        Instant,
+        RTC,
+    },
+    syscfg::SYSCFG,
+};
+
+
+#[entry]
+fn main() -> ! {
+    let cp = pac::CorePeripherals::take().unwrap();
+    let dp = pac::Peripherals::take().unwrap();
+
+    let mut scb   = cp.SCB;
+    let mut rcc   = dp.RCC.freeze(rcc::Config::msi(rcc::MSIRange::Range0));
+    let mut exti  = dp.EXTI;
+    let mut pwr   = PWR::new(dp.PWR, &mut rcc);
+    let     gpiob = dp.GPIOB.split(&mut rcc);
+
+    let mut led = gpiob.pb2.into_push_pull_output().downgrade();
+
+    #[cfg(feature = "stm32l0x1")]
+    let mut syscfg = SYSCFG::new(dp.SYSCFG, &mut rcc);
+    #[cfg(any(feature = "stm32l0x2", feature = "stm32l0x3"))]
+    let mut syscfg = SYSCFG::new(dp.SYSCFG_COMP, &mut rcc);
+
+    let instant = Instant::new()
+        .set_year(19)
+        .set_month(9)
+        .set_day(26)
+        .set_hour(11)
+        .set_minute(57)
+        .set_second(0);
+
+    let mut rtc = RTC::new(dp.RTC, &mut rcc, &mut pwr, instant);
+
+    let exti_line = 20; // RTC wakeup timer
+
+    rtc.enable_interrupts(rtc::Interrupts {
+        wakeup_timer: true,
+        ..rtc::Interrupts::default()
+    });
+    exti.listen(
+        &mut syscfg,
+        gpio::Port::PA, // argument ignored; next argument is not a GPIO line
+        exti_line,
+        exti::TriggerEdge::Rising,
+    );
+
+    let mut timer = rtc.wakeup_timer();
+
+    // Blink twice to signal the start of the program
+    blink(&mut led);
+    blink(&mut led);
+
+    // 5 seconds of regular run mode
+    timer.start(5u32);
+    while let Err(nb::Error::WouldBlock) = timer.wait() {}
+    exti.clear_irq(exti_line);
+    cortex_m::peripheral::NVIC::unpend(pac::Interrupt::RTC);
+
+    blink(&mut led);
+
+    // 5 seconds of low-power run mode
+    pwr.enter_low_power_run_mode(rcc.clocks);
+    while let Err(nb::Error::WouldBlock) = timer.wait() {}
+    pwr.exit_low_power_run_mode();
+    exti.clear_irq(exti_line);
+    cortex_m::peripheral::NVIC::unpend(pac::Interrupt::RTC);
+
+    blink(&mut led);
+
+    // 5 seconds of sleep mode
+    exti.wait_for_irq(
+        exti_line,
+        pwr.sleep_mode(&mut scb),
+    );
+    timer.wait().unwrap(); // returns immediately; we just got the interrupt
+
+    blink(&mut led);
+
+    // 5 seconds of low-power sleep mode
+    exti.wait_for_irq(
+        exti_line,
+        pwr.low_power_sleep_mode(&mut scb, &mut rcc),
+    );
+    timer.wait().unwrap(); // returns immediately; we just got the interrupt
+
+    blink(&mut led);
+
+    // 5 seconds of stop mode
+    exti.wait_for_irq(
+        exti_line,
+        pwr.stop_mode(
+            &mut scb,
+            &mut rcc,
+            pwr::StopModeConfig {
+                ultra_low_power: true,
+            },
+        ),
+    );
+    timer.wait().unwrap(); // returns immediately; we just got the interrupt
+
+    blink(&mut led);
+
+    // 5 seconds of standby mode
+    cortex_m::peripheral::NVIC::unpend(pac::Interrupt::RTC);
+    exti.wait_for_irq(
+        exti_line,
+        pwr.standby_mode(&mut scb),
+    );
+
+    // The microcontroller resets after leaving standby mode. We should never
+    // reach this point.
+    loop {
+        blink(&mut led);
+    }
+}
+
+
+fn blink(led: &mut PB<Output<PushPull>>) {
+    led.set_high().unwrap();
+    delay();
+    led.set_low().unwrap();
+    delay();
+}
+
+fn delay() {
+    // We can't use `Delay`, as that requires a frequency of at least one MHz.
+    // Given our clock selection, the following loop should give us a nice delay
+    // when compiled in release mode.
+    for _ in 0 .. 1_000 { asm::nop() }
+}