use less unstable dependencies

Cargo.toml

@@ -9,11 +9,13 @@ repository = "https://github.com/japaric/cortex-m-quickstart"
 version = "0.2.7"
 
 [dependencies]
-cortex-m = "0.4.0"
-cortex-m-rt = "0.4.0"
-cortex-m-semihosting = "0.2.0"
+# cortex-m = "0.4.0"
+# cortex-m-rt = "0.4.0"
+cortex-m-rt = { git = "https://github.com/japaric/cortex-m-rt", branch = "stable" }
+# cortex-m-semihosting = "0.2.0"
+# panic-loop = { path = "../panic-loop" }
 panic-abort = "0.1.1"
-panic-semihosting = "0.1.0"
+# panic-semihosting = "0.1.0"
 # Uncomment for the allocator example.
 #alloc-cortex-m = "0.3.3"
 

examples/minimal.rs

@@ -0,0 +1,35 @@
+#![no_main] // <- IMPORTANT!
+#![no_std]
+
+#[macro_use]
+extern crate cortex_m_rt;
+extern crate panic_abort;
+
+use core::ptr;
+
+// user entry point
+main!(main);
+
+fn main() -> ! {
+    loop {
+        unsafe {
+            // NOTE side affect to avoid UB
+            ptr::read_volatile(0x2000_0000 as *const u32);
+        }
+    }
+}
+
+// define the default exception handler
+exception!(DefaultHandler, deh);
+
+fn deh(_nr: u8) -> ! {
+    loop {
+        unsafe {
+            // NOTE side affect to avoid UB
+            ptr::read_volatile(0x2000_0004 as *const u32);
+        }
+    }
+}
+
+// bind all interrupts to the default exception handler
+interrupts!(DefaultHandler);

interrupts.x

@@ -0,0 +1 @@
+/* Remove this file if you are linking to a device crate that provides this file */