panic: always turn on red leds, and halt

Cargo.lock

@@ -520,12 +520,6 @@ dependencies = [
  "autocfg",
 ]
 
-[[package]]
-name = "panic-halt"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "de96540e0ebde571dc55c73d60ef407c653844e6f9a1e2fdbd40c07b9252d812"
-
 [[package]]
 name = "panic-semihosting"
 version = "0.5.6"
@@ -729,7 +723,6 @@ dependencies = [
  "mcp23017",
  "miniconf",
  "nb 1.0.0",
- "panic-halt",
  "panic-semihosting",
  "paste",
  "serde",

Cargo.toml

@@ -33,7 +33,6 @@ cortex-m-rt = { version = "0.6", features = ["device"] }
 cortex-m-log = { version = "0.7", features = ["log-integration"] }
 log = "0.4"
 panic-semihosting = { version = "0.5", optional = true }
-panic-halt = "0.2"
 serde = { version = "1.0", features = ["derive"], default-features = false }
 heapless = { version = "0.5", features = ["serde"] }
 cortex-m-rtic = "0.5.5"

src/hardware/mod.rs

@@ -4,9 +4,6 @@ use stm32h7xx_hal as hal;
 #[cfg(feature = "semihosting")]
 use panic_semihosting as _;
 
-#[cfg(not(any(feature = "nightly", feature = "semihosting")))]
-use panic_halt as _;
-
 mod adc;
 mod afe;
 mod configuration;
@@ -47,15 +44,15 @@ pub use configuration::{setup, PounderDevices, StabilizerDevices};
 
 #[inline(never)]
 #[panic_handler]
-#[cfg(all(feature = "nightly", not(feature = "semihosting")))]
+#[cfg(all(not(feature = "semihosting")))]
 fn panic(_info: &core::panic::PanicInfo) -> ! {
     let gpiod = unsafe { &*hal::stm32::GPIOD::ptr() };
-    gpiod.odr.modify(|_, w| w.odr6().high().odr12().high()); // FP_LED_1, FP_LED_3
-    #[cfg(feature = "nightly")]
-    core::intrinsics::abort();
-    #[cfg(not(feature = "nightly"))]
-    unsafe {
-        core::intrinsics::abort();
+    // Turn on both red LEDs, FP_LED_1, FP_LED_3
+    gpiod.odr.modify(|_, w| w.odr6().high().odr12().high());
+    loop { // Halt
+        core::sync::atomic::compiler_fence(
+            core::sync::atomic::Ordering::SeqCst,
+        );
     }
 }
 
@@ -63,8 +60,3 @@ fn panic(_info: &core::panic::PanicInfo) -> ! {
 fn HardFault(ef: &cortex_m_rt::ExceptionFrame) -> ! {
     panic!("HardFault at {:#?}", ef);
 }
-
-#[cortex_m_rt::exception]
-fn DefaultHandler(irqn: i16) {
-    panic!("Unhandled exception (IRQn = {})", irqn);
-}