add rgb check and example

examples/embassy-rgb-check/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "embassy-rgb-check"
+version = "0.1.0"
+edition = "2024"
+publish = false
+build = "build.rs"
+
+[dependencies]
+cortex-m.workspace = true
+cortex-m-rt.workspace = true
+defmt.workspace = true
+defmt-rtt.workspace = true
+embassy-executor = { workspace = true, features = ["defmt", "executor-thread", "platform-cortex-m"] }
+embassy-stm32 = { workspace = true, features = ["defmt", "stm32f103c8", "time-driver-tim3"] }
+embassy-time.workspace = true
+panic-probe.workspace = true

examples/embassy-rgb-check/build.rs

@@ -0,0 +1,12 @@
+// main: tell Cargo to rerun when memory.x changes and add the shared link path.
+// Input: none.
+// Output: build script side effects only.
+fn main() {
+    println!("cargo:rerun-if-changed=../../memory.x");
+    println!(
+        "cargo:rustc-link-search={}",
+        std::path::PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap())
+            .join("../..")
+            .display()
+    );
+}

examples/embassy-rgb-check/src/main.rs

@@ -0,0 +1,70 @@
+#![deny(unsafe_code)]
+#![no_std]
+#![no_main]
+
+use cortex_m as _;
+use defmt::info;
+use defmt_rtt as _;
+use embassy_executor::Spawner;
+use embassy_stm32::gpio::{Level, Output, Speed};
+use embassy_time::Timer;
+use panic_probe as _;
+
+const HOLD_MS: u64 = 1000;
+
+// main: cycle each RGB pin high and low in order so the LED wiring can be checked.
+// Input: the Embassy spawner, which this example does not use.
+// Output: never returns.
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_stm32::init(Default::default());
+    let _gnd = Output::new(p.PA0, Level::Low, Speed::Low);
+    let mut red = Output::new(p.PA1, Level::Low, Speed::Low);
+    let mut green = Output::new(p.PA2, Level::Low, Speed::Low);
+    let mut blue = Output::new(p.PA3, Level::Low, Speed::Low);
+    let mut led = Output::new(p.PC13, Level::High, Speed::Low);
+
+    loop {
+        info!("expected: red high, green low, blue low");
+        red.set_high();
+        green.set_low();
+        blue.set_low();
+        led.set_low();
+        Timer::after_millis(HOLD_MS).await;
+
+        info!("expected: red low, green low, blue low");
+        red.set_low();
+        green.set_low();
+        blue.set_low();
+        led.set_high();
+        Timer::after_millis(HOLD_MS).await;
+
+        info!("expected: red low, green high, blue low");
+        red.set_low();
+        green.set_high();
+        blue.set_low();
+        led.set_low();
+        Timer::after_millis(HOLD_MS).await;
+
+        info!("expected: red low, green low, blue low");
+        red.set_low();
+        green.set_low();
+        blue.set_low();
+        led.set_high();
+        Timer::after_millis(HOLD_MS).await;
+
+        info!("expected: red low, green low, blue high");
+        red.set_low();
+        green.set_low();
+        blue.set_high();
+        led.set_low();
+        Timer::after_millis(HOLD_MS).await;
+
+        info!("expected: red low, green low, blue low");
+        red.set_low();
+        green.set_low();
+        blue.set_low();
+        led.set_high();
+        Timer::after_millis(HOLD_MS).await;
+    }
+}