use RTT for PanicInfo

src/device/boot.rs

@@ -1,4 +1,4 @@
-use super::{gpio, log_setup, sys_timer, usb};
+use super::{gpio, sys_timer, usb};
 use crate::laser_diode::current_sources::*;
 use fugit::ExtU32;
 use log::info;
@@ -15,9 +15,6 @@ const WATCHDOG_PERIOD: u32 = 1000;
 const WATCHDOG_PERIOD: u32 = 30000;
 
 pub fn bootup(mut core_perif: CorePeripherals, perif: Peripherals) -> IndependentWatchdog {
-    log_setup::init_log();
-    info!("Kirdy init");
-
     core_perif.SCB.enable_icache();
     core_perif.SCB.enable_dcache(&mut core_perif.CPUID);
 

src/device/log_setup.rs

@@ -9,9 +9,7 @@ pub fn init_log() {
 #[cfg(feature = "RTT")]
 pub fn init_log() {
     use super::rtt_logger;
-    use rtt_target::rtt_init_print;
     static RTT_LOGGER: rtt_logger::Logger = rtt_logger::Logger;
-    rtt_init_print!();
     let _ = log::set_logger(&RTT_LOGGER);
     log::set_max_level(log::LevelFilter::Debug);
 }

src/main.rs

@@ -3,15 +3,38 @@
 
 use cortex_m_rt::entry;
 use log::info;
-use panic_halt as _;
 use stm32f4xx_hal::pac::{CorePeripherals, Peripherals};
 
 mod device;
 mod laser_diode;
-use device::{boot::bootup, sys_timer};
+use device::{boot::bootup, log_setup, sys_timer};
+
+// If RTT is used, print panic info through RTT
+#[cfg(feature = "RTT")]
+use {
+    core::panic::PanicInfo,
+    rtt_target::{rprintln, rtt_init_print},
+};
+#[cfg(feature = "RTT")]
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    rprintln!("{}", info);
+    loop {}
+}
+// Otherwise use panic halt
+#[cfg(not(feature = "RTT"))]
+use panic_halt as _;
 
 #[entry]
 fn main() -> ! {
+    
+    // RTT does not rely on any peripherals, can be set up immidiately
+    #[cfg(feature = "RTT")]
+    rtt_init_print!();
+
+    log_setup::init_log();
+    info!("Kirdy init");
+
     let core_perif = CorePeripherals::take().unwrap();
     let perif = Peripherals::take().unwrap();