Drop support for Arduino (#59)

* Drop support for Arduino

* Update lint CI and test it

* Fix lint

.github/workflows/opensmartmeter.yaml

@@ -16,7 +16,7 @@ jobs:
       - uses: actions/checkout@v3
       - name: Run clang-format lint
         working-directory: Firmware code/smart_energy_meter
-        run: clang-format --style=file -n --Werror smart_energy_meter.ino
+        run: find include/ lib/ src/ \( -name '*.[ch]pp' -o -name '*.h' \) | xargs clang-format --verbose --style=file -n --Werror
   editorconfig-checker:
     name: Lint EditorConfig
     runs-on: ubuntu-latest
@@ -29,21 +29,6 @@ jobs:
       - name: Run editorconfig-checker
         working-directory: Firmware code/smart_energy_meter
         run: ec
-  compile-firmware-arduino-cli:
-    name: Compile Firmware with Arduino CLI
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - name: Install Arduino CLI
-        uses: arduino/setup-arduino-cli@v1
-      - name: Install board and platform
-        working-directory: Firmware code/smart_energy_meter
-        run: |
-          make install
-      - name: Compile the firmware
-        working-directory: Firmware code/smart_energy_meter
-        run: |
-          make compile
   compile-firmware-platform-io:
     name: Compile Firmware with PlatformIO
     runs-on: ubuntu-latest

Firmware code/smart_energy_meter/include/README

@@ -0,0 +1,39 @@
+
+This directory is intended for project header files.
+
+A header file is a file containing C declarations and macro definitions
+to be shared between several project source files. You request the use of a
+header file in your project source file (C, C++, etc) located in `src` folder
+by including it, with the C preprocessing directive `#include'.
+
+```src/main.c
+
+#include "header.h"
+
+int main (void)
+{
+ ...
+}
+```
+
+Including a header file produces the same results as copying the header file
+into each source file that needs it. Such copying would be time-consuming
+and error-prone. With a header file, the related declarations appear
+in only one place. If they need to be changed, they can be changed in one
+place, and programs that include the header file will automatically use the
+new version when next recompiled. The header file eliminates the labor of
+finding and changing all the copies as well as the risk that a failure to
+find one copy will result in inconsistencies within a program.
+
+In C, the usual convention is to give header files names that end with `.h'.
+It is most portable to use only letters, digits, dashes, and underscores in
+header file names, and at most one dot.
+
+Read more about using header files in official GCC documentation:
+
+* Include Syntax
+* Include Operation
+* Once-Only Headers
+* Computed Includes
+
+https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html

Firmware code/smart_energy_meter/lib/README

@@ -0,0 +1,46 @@
+
+This directory is intended for project specific (private) libraries.
+PlatformIO will compile them to static libraries and link into executable file.
+
+The source code of each library should be placed in a an own separate directory
+("lib/your_library_name/[here are source files]").
+
+For example, see a structure of the following two libraries `Foo` and `Bar`:
+
+|--lib
+|  |
+|  |--Bar
+|  |  |--docs
+|  |  |--examples
+|  |  |--src
+|  |     |- Bar.c
+|  |     |- Bar.h
+|  |  |- library.json (optional, custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
+|  |
+|  |--Foo
+|  |  |- Foo.c
+|  |  |- Foo.h
+|  |
+|  |- README --> THIS FILE
+|
+|- platformio.ini
+|--src
+   |- main.c
+
+and a contents of `src/main.c`:
+```
+#include <Foo.h>
+#include <Bar.h>
+
+int main (void)
+{
+  ...
+}
+
+```
+
+PlatformIO Library Dependency Finder will find automatically dependent
+libraries scanning project source files.
+
+More information about PlatformIO Library Dependency Finder
+- https://docs.platformio.org/page/librarymanager/ldf.html

Firmware code/smart_energy_meter/platformio.ini

@@ -8,10 +8,6 @@
 ; Please visit documentation for the other options and examples
 ; https://docs.platformio.org/page/projectconf.html
 
-[platformio]
-# This is needed for interoperability with ArduinoIDE
-src_dir = .
-
 [env:bluepill_f103c8_128k]
 framework = arduino
 # Using a more recent version of STM32 platform fails with

Firmware code/smart_energy_meter/test/README

@@ -0,0 +1,11 @@
+
+This directory is intended for PlatformIO Test Runner and project tests.
+
+Unit Testing is a software testing method by which individual units of
+source code, sets of one or more MCU program modules together with associated
+control data, usage procedures, and operating procedures, are tested to
+determine whether they are fit for use. Unit testing finds problems early
+in the development cycle.
+
+More information about PlatformIO Unit Testing:
+- https://docs.platformio.org/en/latest/advanced/unit-testing/index.html