Get compass solution working and add more information.

src/exercises/bare-metal/compass.md

@@ -17,3 +17,11 @@ use microbit::{hal::uarte::{Baudrate, Parity, Uarte}, Board};
     }
 }
 ```
+
+See the serial output with
+
+```sh
+picocom --baud 115200 --imap lfcrlf /dev/ttyACM0
+```
+
+Use Ctrl+A Ctrl+Q to quit picocom.

src/exercises/bare-metal/compass/.cargo/config.toml

@@ -1,2 +1,5 @@
 [build]
 target = "thumbv7em-none-eabihf" # Cortex-M4F
+
+[target.'cfg(all(target_arch = "arm", target_os = "none"))']
+rustflags = ["-C", "link-arg=-Tlink.x"]

src/exercises/bare-metal/compass/Embed.toml

@@ -1,2 +1,8 @@
 [default.general]
 chip = "nrf52833_xxAA"
+
+[debug.gdb]
+enabled = true
+
+[debug.reset]
+halt_afterwards = true