Rust edition bumped & UART implementation

- Also adds UART example

examples/tests.rs

@@ -72,7 +72,9 @@ fn main() -> ! {
         }
         TestCase::TestPullup => {
             // Tie PORTA[0] to PORTA[1] for these tests!
-            let input = porta.pa1.into_pull_up_input(&mut dp.IOCONFIG);
+            let input = porta
+                .pa1
+                .into_pull_up_input(&mut dp.IOCONFIG, &mut dp.PORTA);
             assert!(input.is_high().unwrap());
             let mut out = porta
                 .pa0

examples/uart.rs

@@ -0,0 +1,44 @@
+//! UART example application. Sends a test string over a UART and then enters
+//! echo mode
+#![no_main]
+#![no_std]
+
+use core::fmt::Write;
+use cortex_m_rt::entry;
+use panic_rtt_target as _;
+use rtt_target::{rprintln, rtt_init_print};
+use va108xx_hal::{pac, prelude::*, uart};
+
+#[entry]
+fn main() -> ! {
+    rtt_init_print!();
+    rprintln!("-- VA108xx UART test application--");
+
+    let mut dp = pac::Peripherals::take().unwrap();
+
+    let gpiob = dp.PORTB.split(&mut dp.SYSCONFIG).unwrap();
+    let tx = gpiob.pb21.into_funsel_1(&mut dp.IOCONFIG);
+    let rx = gpiob.pb20.into_funsel_1(&mut dp.IOCONFIG);
+
+    let uartb = uart::Uart::uartb(
+        dp.UARTB,
+        (tx, rx),
+        115200.bps(),
+        &mut dp.SYSCONFIG,
+        50.mhz().into(),
+    );
+    let (mut tx, mut rx) = uartb.split();
+    writeln!(tx, "Hello World\r").unwrap();
+    loop {
+        // Echo what is received on the serial link.
+        match rx.read() {
+            Ok(recv) => {
+                nb::block!(tx.write(recv)).expect("TX send error");
+            }
+            Err(nb::Error::WouldBlock) => (),
+            Err(nb::Error::Other(uart_error)) => {
+                rprintln!("UART receive error {:?}", uart_error);
+            }
+        }
+    }
+}