custom panic to preserve type checking

src/main.rs

@@ -3,13 +3,38 @@
 
 use arduino_hal::prelude::*;
 
-panic_serial::impl_panic_handler!(
-  arduino_hal::usart::Usart<
-    arduino_hal::pac::USART0,
-    arduino_hal::port::Pin<arduino_hal::port::mode::Input, arduino_hal::hal::port::PD0>,
-    arduino_hal::port::Pin<arduino_hal::port::mode::Output, arduino_hal::hal::port::PD1>
-  >
-);
+// NOTE: 115200 @ 16MHz is 3.5% off, try 9600 or 1M if it causes issues (https://wormfood.net/avrbaudcalc.php)
+const SERIAL_BAUD: u32 = 115200;
+
+#[cfg(not(doc))]
+#[panic_handler]
+fn panic(info: &core::panic::PanicInfo) -> ! {
+    // disable interrupts - firmware has panicked so no ISRs should continue running
+    // avr_device::interrupt::disable();
+
+    // SAFETY: Main code aborted.
+    let dp = unsafe { arduino_hal::Peripherals::steal() };
+    let pins = arduino_hal::pins!(dp);
+    let mut serial = arduino_hal::default_serial!(dp, pins, SERIAL_BAUD);
+
+    ufmt::uwriteln!(&mut serial, "Firmware panic!\r").unwrap_infallible();
+    if let Some(loc) = info.location() {
+        ufmt::uwriteln!(
+            &mut serial,
+            "  At {}:{}:{}\r",
+            loc.file(),
+            loc.line(),
+            loc.column(),
+        )
+        .unwrap_infallible();
+    }
+
+    let mut led = pins.d13.into_output();
+    loop {
+        led.toggle();
+        arduino_hal::delay_ms(100);
+    }
+}
 
 #[arduino_hal::entry]
 fn main() -> ! {
@@ -17,9 +42,7 @@ fn main() -> ! {
     let pins = arduino_hal::pins!(dp);
 
     let mut led = pins.d13.into_output();
-    // NOTE: 115200 @ 16MHz is 3.5% off, try 9600 or 1M if it causes issues (https://wormfood.net/avrbaudcalc.php)
-    let serial = arduino_hal::default_serial!(dp, pins, 115200);
-    let mut serial = share_serial_port_with_panic(serial);
+    let mut serial = arduino_hal::default_serial!(dp, pins, SERIAL_BAUD);
 
     ufmt::uwriteln!(&mut serial, "Hello from Arduino!").unwrap_infallible();