examples: add simple software task example

While we do have a dedicated repo for RTIC examples, it makes more sense
to merge those too with this repo: cargo-rtic-scope, cortem-m-rtic-trace
and relevant examples are all interlinked and must be in phase with
eachother.

However, we can't add it to the workspace yet because
per-package-target[0] is not yet stable.

[0] rust-lang/cargo#9406

.github/workflows/build.yml

@@ -27,7 +27,13 @@ jobs:
           override: true
           components: rustfmt
 
-      - name: cargo fmt -- --check
+      - name: check workspace formatting
+        uses: actions-rs/cargo@v1
+        with:
+          command: fmt
+          args: -- --check
+      - run: cd ./examples
+      - name: check examples formatting
         uses: actions-rs/cargo@v1
         with:
           command: fmt
@@ -92,7 +98,7 @@ jobs:
           target: ${{ matrix.target }}
           override: true
 
-      - name: cargo build
+      - name: build workspace
         uses: actions-rs/cargo@v1
         with:
           command: build
@@ -102,6 +108,12 @@ jobs:
         with:
           name: cargo-rtic-scope
           path: target/${{ matrix.target }}/debug/cargo-rtic-scope
+      - run: rustup target add thumbv7em-none-eabihf
+      - run: cd ./examples && pwd
+      - name: build examples
+        uses: actions-rs/cargo@v1
+        with:
+          command: build
 
   resolve:
     name: trace --resolve-only

examples/.cargo/config

@@ -0,0 +1,8 @@
+[target.thumbv7em-none-eabihf]
+rustflags = [
+    "-C", "link-arg=-Tlink.x",
+    "-C", "linker=arm-none-eabi-ld",
+]
+
+[build]
+target = "thumbv7em-none-eabihf"

examples/.gitignore

@@ -0,0 +1 @@
+target/