stm32: add USB driver.

examples/stm32l5/src/bin/rng.rs

@@ -0,0 +1,34 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use defmt_rtt as _; // global logger
+use embassy::executor::Spawner;
+use embassy_stm32::rcc::{ClockSrc, PLLClkDiv, PLLMul, PLLSource, PLLSrcDiv};
+use embassy_stm32::rng::Rng;
+use embassy_stm32::{Config, Peripherals};
+use panic_probe as _;
+
+fn config() -> Config {
+    let mut config = Config::default();
+    config.rcc.mux = ClockSrc::PLL(
+        PLLSource::HSI16,
+        PLLClkDiv::Div2,
+        PLLSrcDiv::Div1,
+        PLLMul::Mul8,
+        Some(PLLClkDiv::Div2),
+    );
+    config
+}
+
+#[embassy::main(config = "config()")]
+async fn main(_spawner: Spawner, p: Peripherals) {
+    info!("Hello World!");
+
+    let mut rng = Rng::new(p.RNG);
+
+    let mut buf = [0u8; 16];
+    unwrap!(rng.async_fill_bytes(&mut buf).await);
+    info!("random bytes: {:02x}", buf);
+}