Initial commit

src/bin/12_embassy.rs

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+// Embassy async loop.
+// Show timers, tasks, and printing together.
+// This is why a framework can beat a hand-written loop.
+
+#![allow(unsafe_code)]
+#![no_std]
+#![no_main]
+
+use cortex_m_semihosting::hprintln;
+use embassy_executor::Spawner;
+use embassy_time::{Duration, Ticker, Timer};
+use panic_probe as _;
+
+// Stub out interrupts that the PAC expects but this chapter does not use.
+#[allow(non_snake_case)]
+#[unsafe(no_mangle)]
+pub extern "C" fn USB_HP_CAN1_TX() {}
+
+// Stub out interrupts that the PAC expects but this chapter does not use.
+#[allow(non_snake_case)]
+#[unsafe(no_mangle)]
+pub extern "C" fn USB_LP_CAN1_RX0() {}
+
+// Stub out interrupts that the PAC expects but this chapter does not use.
+#[allow(non_snake_case)]
+#[unsafe(no_mangle)]
+pub extern "C" fn CAN1_RX1() {}
+
+// Stub out interrupts that the PAC expects but this chapter does not use.
+#[allow(non_snake_case)]
+#[unsafe(no_mangle)]
+pub extern "C" fn CAN1_SCE() {}
+
+// Stub out interrupts that the PAC expects but this chapter does not use.
+#[allow(non_snake_case)]
+#[unsafe(no_mangle)]
+pub extern "C" fn RTC_ALARM() {}
+
+// Stub out interrupts that the PAC expects but this chapter does not use.
+#[allow(non_snake_case)]
+#[unsafe(no_mangle)]
+pub extern "C" fn USBWAKEUP() {}
+
+#[embassy_executor::task]
+async fn heartbeat() {
+    let mut ticker = Ticker::every(Duration::from_secs(1));
+
+    loop {
+        ticker.next().await;
+        hprintln!("embassy heartbeat");
+    }
+}
+
+#[embassy_executor::main]
+async fn main(spawner: Spawner) {
+    let _p = embassy_stm32::init(Default::default());
+
+    hprintln!("embassy boot");
+    spawner.spawn(heartbeat()).unwrap();
+
+    loop {
+        Timer::after_secs(2).await;
+        hprintln!("embassy main loop");
+    }
+}