Overview#

This method is a wonderful bridge between beginner and intermediate in a sense from automated script from Arduino IDE to define your very own flags to feed the compiler. That is, before you just “need to” (or to be perfectly candid “only-able-to”) hit compile button.

After this, you will be able to comprehend a concept of Makefile and further working with Makefile in raw .c and .cpp format and even with other compiler, e.g. GNU C++ Compiler (GCC).

That being said, this approach utilizes pre-defined routine from Arduino IDE itself such as board variant, microcontroller architecture to monitor port on your computer and furthermore.

Prerequisite#

1. An application running Shell (Command Line Interpreter) typically Terminal on macOS.

2. A Package Manager, typically homebrew (macOS) or apt-get, yum on a variety of Linux distros.

3. A C Compiler, specifically OSX-GCC Compiler if you are on macOS which will be installed along with the Xcode application.

4. A Python interpreter and Python-specific Package Manager: pip for Python 2.7 or pip3 for Python 3.

Don’t worry if you are missing any of those !! A comprised instruction can be found below

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

vim ~/.bash_profile
# Place this line into the profile
export PATH="/usr/local/bin:/usr/local/sbin:$PATH

/usr/bin/xcodebuild -version

xcode-select --install

whereis gcc
~ /usr/bin/gcc

brew install python@2

vim ~/.bash_profile
# Place this line into the profile
export PATH="/usr/local/opt/python@2/bin:$PATH"

Toolchain Installation#

In case you are an intrinsic newbie, definitely check out the Prerequisite instruction above. Once having all the application and dependencies, the main toolchains are required to setup.

• Arduino IDE & AVR-G++ Compiler

Download the latest version of Arduino IDE from arduino.cc ↗ which includes the AVR-G++ Compiler. Drag & Drop the Arduino IDE into Application folder (important).

Once installed, the compiler can be verified by using command

/Applications/Arduino.app/Contents/Java/hardware/tools/avr/bin/avr-g++ --version

• Makefile workflow

(Recommended) Using homebrew or apt-get to install directly with command

brew update
brew tap sudar/arduino-mk
brew install arduino-mk

Another way is if you are familiar with GitHub, clone the directory sudar/Arduino-Makefile ↗ and extract the .ZIP into /usr/bin/Cellar.

• PySerial tool

The Arduino IDE provides avrdude to work with uploading code to the board and by using Pyserial program, this process can be further automated.

(Recommended) Install using the pip, Package Manager for Python 2.7 package with the command.

pip install pyserial

Another way is to install it as a package with apt-get install python-serial.

Understanding Arduino#

Now that every dependencies are satisfied, let’s take a look into how components on Arduino board and controller peripherals operated as well as compiler directive.

Hardware Level#

At Hardware Level, an Arduino Board, e.g. Uno, Leonardo, Mega, etc.; typically contains a main AVR microcontroller (ATmega328p, ATmega32u4, ATmega2560 respectively) from Atmel and hence the controller names.

Beside that, a common microcontroller ATmega16u2 is usually in charge of convert between the computer’s USB port and the main controller’s serial port.

Arduino Uno and Hardware Interface between computer to the microcontroller

This bridge is essential for uploading code from the computer to the main controller’s memory and communicating with it via serial protocol as discussed in the embedded system article ↗.

Software Level#

At Software Level, Arduino IDE provides a medium between the user and the AVR-G++ compiler. That is, it completes function pre-define, header, library linking and ultimately export machine-understandable directive, usually in .hex format.

The nature of an Arduino sketch is nothing else but C, C++ code and parameter directive as well as other “under the hood” declaration, for instance look at the way CPU clock speed defined below.

Makefile Flags#

In the Makefile, some usual parameters are defined for the board, port, user Library and one important line to include the directive Arduino.mk file.

Hint: The full list of Arduino boards can be found inside the Arduino.app or simply run make show_boards and make show_submenu respectively.

BOARD_TAG    = mega
BOARD_SUB    = atmega2560

ARDUINO_LIBS = SoftwareSerial

MONITOR_PORT = /dev/*.usbserial*
MONITOR_BAUDRATE = 115200

include ../../Arduino.mk

Typical Makefile script for Arduino Mega board

Routine Usage#

The usage is quite straight forward with a few commands and a Makefile in the **same directory **as the Arduino sketch .ino.

These commands are pretty self-explanatory using a prefix make with flags:

Output of Compile-Only command make

Output of Compile-and-Upload command make upload using PySerial to trigger reset

Establish serial connection command make monitor using native app screen on macOS 10.14.1

Advance to AVR Development#

If you are feeling confident enough, explores these new aspects:

1. Compiling plain AVR C programs: Also look up Atmel Studio for an IDE with troubleshooting.
2. Program using Arduino as ISP: Bootload firmware form one to another board (More on upcoming article).
3. Generate assembly and symbol files: Understand more of file linking and how compiler works.

Troubleshooting (Extra)#

“Command Not Found” for missing Shell Path In case of homebrew or Python commands not found, try to refresh it

export PATH="/usr/local/bin:/usr/local/sbin:$PATH”
source /.bashprofile

Or better yet, look into ~/.bashrc instead.

Python 3 and Python 2 compatibility

Python > 3.5 is NOT backwards compatible and thus some of the dependencies might be newer than wanted. One solution is to switch using homebrew.

brew switch python 2.7.x

Also, make sure to use the correct commands in execution, i.e. pip/pip2 or python/python2.