start adding embassy example

examples/embassy/src/main.rs

@@ -0,0 +1,23 @@
+#![no_std]
+#![no_main]
+use embassy_executor::Spawner;
+use embassy_time::Timer;
+use embedded_hal::digital::StatefulOutputPin;
+use panic_rtt_target as _;
+use rtt_target::{rprintln, rtt_init_print};
+use va416xx_hal::{gpio::PinsG, pac};
+
+// main is itself an async function.
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    rtt_init_print!();
+    rprintln!("VA416xx RTT Demo");
+
+    let mut dp = pac::Peripherals::take().unwrap();
+    let portg = PinsG::new(&mut dp.sysconfig, dp.portg);
+    let mut led = portg.pg5.into_readable_push_pull_output();
+    loop {
+        Timer::after_millis(200).await;
+        led.toggle().ok();
+    }
+}