A makefile for ESP8266 and ESP32 Arduino projects
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A makefile for ESP8266 and ESP32 Arduino projects.

The main intent for this project is to provide a minimalistic yet powerful and easy configurable makefile for projects using the ESP/Arduino framework available at: https://github.com/esp8266/Arduino and https://github.com/espressif/arduino-esp32

Using make instead of the Arduino IDE makes it easier to do more production oriented builds of software projects.

This makefile basically gives you a command line tool for easy building and loading of the ESP/Arduino examples as well as your own projects.

The makefile can use the ESP/Arduino environment either from the installation within the Arduino IDE or in a separate git clone of the environment. The latter can be useful in project where you want stringent control of the environment version e.g. by using it as a git submodule.

You basically just have to specify your main sketch file and the libraries it uses. The libraries can be from arbitrary directories without any required specific hierarchy or any of the other restrictions which normally apply to builds made from within the Arduino IDE. The makefile will find all involved header and source files automatically.

The makefile will also automatically produce header and c files which contain information about the time when the build (link) was performed. This file also includes the git descriptions (tag) of the used version of the ESP/Arduino environment and the project source (when applicable). This can be used by the project source files to provide stringent version information from within the software.

Rules for building the firmware as well as upload it to the ESP board are provided.

It is also possible to let the makefile generate and upload a complete SPIFFS file system based on an arbitrary directory of files.

The intension is to use the makefile as is. Possible specific configuration is done via via makefile variables supplied on the command line or in separate companion makefiles.

The makefile can be used on Linux, Mac OS and Microsoft Windows (Cygwin).

The actual build commands (compile, link etc.) are extracted from the Arduino description files (platform.txt etc.).

Uploading of the built binary can be made via serial channel (esptool), ota (espota.py) or http (curl). Which method to use is controlled by makefile target selection. By default the serial channel is used.


First make sure that you have the environment installed as described at: https://github.com/esp8266/Arduino and https://github.com/espressif/arduino-esp32
If you don't want to use the environment installed in the Arduino IDE, then you can to clone it into a separate directory instead, see below.

Then start cloning the makeEspArduino repository.

cd ~
git clone https://github.com/plerup/makeEspArduino.git

After this you can test it. Attach your ESP8266 board and execute the following commands:

cd makeEspArduino
make -f makeEspArduino.mk DEMO=1 flash

The DEMO definition makes the the makefile choose a typical demo sketch from the ESP examples. After this you will have the example downloaded onto in your ESP.

If you want to use a clone of the environment instead then do something like this:

cd ~
git clone https://github.com/esp8266/Arduino.git esp8266
cd esp8266

Determine which version you want to use. See releases. Example:

git checkout tags/2.3.0

Then install the required environment tools by issuing the following commands:

cd tools
python get.py

To test this installation you have to specify the location of the environment when running make

cd ~/makeEspArduino
make -f makeEspArduino.mk ESP_ROOT=~/esp8266 DEMO=1 flash

For ESP32 project the current setup doesn't enable automatic detection of the esp32 environment and hence the variable ESP_ROOT must always be defined.

When building ESP32 projects the variable CHIP must also always be defined, example:

make -f makeEspArduino.mk ESP_ROOT=~/esp32 CHIP=esp32 DEMO=1 flash

Getting help

A description of all available makefile functions and variables is always available via the following command:

make -f makeEspArduino.mk help

Building projects

You can now use the makefile to build your own sketches or any of the examples in the ESP/Arduino environment. The makefile will automatically search for a sketch in the current directory and build it if found. It is also possible to specify the location of the sketch on the command line. You may want to specify an alias first to minimize typing.

alias espmake="make -f ~/makeEspArduino/makeEspArduino.mk"
# Or when using a clone
alias espmake="make -f ~/makeEspArduino/makeEspArduino.mk ESP_ROOT=~/esp8266"
# For esp32
alias espmake32="make -f ~/makeEspArduino/makeEspArduino.mk CHIP=esp32 ESP_ROOT=~/esp32"
Some examples

In current directory:

cd ~/.arduino15/packages/esp8266/hardware/esp8266/2.3.0/libraries/Ticker/examples/TickerBasic

Explicit naming of a default directory:

espmake -C ~/.arduino15/packages/esp8266/hardware/esp8266/2.3.0/libraries/Ticker/examples/TickerBasic

Explicit naming of the sketch:

espmake SKETCH=~/.arduino15/packages/esp8266/hardware/esp8266/2.3.0/libraries/Ticker/examples/TickerBasic/TickerBasic.ino
# Or like this
espmake SKETCH="\$(ESP_ROOT)/libraries/Ticker/examples/TickerBasic/TickerBasic.ino"

Advanced usage

The makefile has several variables which control the build. There are different ways to change the defaults of these variables.

The simplest and most direct way to do this is by specifying the variables and their values on the command line.

The more permanent way is to create a special makefile with the appropriate values for the variables and then include this in the build. This can be achieved either by including makeEspArduino.mk in this file or the other way around by letting makeEspArduino.mk include it. The advantage with the latter method is that the makefile doesn't need to know the location of makeEspArduino.mk, more about this in the examples below.

The most important variables in the makefile are listed below:

SKETCH is the path to the main source file. As stated above, if this is missing then makeEspArduino will try to locate it in the current directory.

LIBS is a variable which can contain a list of explicit source files and/or directories with multiple source files, which are to be compiled and used as libraries in the build. Please note that there is no restrictions regarding location and naming of these files as in the Arduino IDE build system. If you want to achieve automatic search for libraries leave this variable undefined. In this case makeEspArduino will try to recursively locate all required libraries by parsing the include statements in the sketch source file (and other source files in the sketch directory). Libraries in the ESP/Arduino library structure and the standard Arduino library tree will be searched. It is also possible to add other directories/file to search by defining the variable CUSTOM_LIBS.

Source files (.S, .c, .cpp) and libraries (.a) are valid to specify here either direct with a full file path or in wildcard via a directory name.

Please note though that if you want stringent version controlled builds, then define LIBS yourself and set it to version controlled directories/files. All source files located in the same directory as the sketch will also be included automatically. The variable EXCLUDE_DIRS can be setup to exclude one or several directories from the wildcard search.

CHIP Set to either esp8266 (default) or esp32

BOARD The type of ESP8266 or ESP32 board you are using

BUILD_DIR All intermediate build files (object, map files etc.) are stored in a separate directory controlled by this variable. By default this is set to a name consisting of the project and board names. This is just the directory name, the root of this directory is controlled by the variable BUILD_ROOT. Default for this is /tmp/mkESP but it can be set to a non-temporary location if so is desired.

BUILD_EXTRA_FLAGS this variable can be setup to add additional parameters for the compilation commands. It will be placed last and thereby it is possible to override the preceding default ones.

There are some other important variables which corresponds to the settings which you normally do in the "Tools" menu in the Arduino IDE. The makefile will parse the Arduino IDE configuration files and use the same defaults as you would get when after selecting a board in the "Tools" menu.

The result of the parsing is stored as variables in a separate intermediate makefile named 'arduino.mk' in the directory defined by the variable BUILD_DIR. Look into this file if you need to control even more detailed settings variables.

As stated above you can always get a description of all makefile operations, configuration variables and their default values via the 'help' function

espmake help
Automatic rebuild

Another special feature of this makefile is that it keeps a record of the command line parameters and git versions used in the latest build. If any of these are changed during the next build, e.g. changing a variable definition, a complete rebuild is made in order to ensure that all possible changes are applied.

Including the makefile

The easiest way to control the makefile is by defining the desired values of the control variables in your own makefile and then include makeEspArduino.mk. Example:

# My makefile
SKETCH = $(ESP_ROOT)/libraries/Ticker/examples/TickerBasic/TickerBasic.ino

UPLOAD_PORT = /dev/ttyUSB1
BOARD = esp210

include $(HOME)/makeEspArduino/makeEspArduino.mk

Another possibility is to do this the other way around, i.e. let makeEspArduino include your makefile instead. This can be achieved by naming your makefile "config.mk". makeEspArduino will always check for a file with this name in the current directory or in the same directory as the sketch. If you want to use another name for your makefile you can specify this via the variable PROJ_CONF on the command line. Example of such a makefile:

# config.mk
THIS_DIR := $(realpath $(dir $(realpath $(lastword $(MAKEFILE_LIST)))))
ROOT := $(THIS_DIR)/..
  $(ESP_LIBS)/Wire \
  $(ESP_LIBS)/ESP8266WiFi \
  $(ROOT)/libraries \


It is of course also always possible to control the variable values in the makefile by defining them as environment variables in the shell. Example:

export UPLOAD_PORT=/dev/ttyUSB2

Flash operations for esp8266

The Arduino configuration files for esp8266 currently specifies "esptool ck" as the tool to be used for flashing operations. The alternative "esptool.py" (which is used for esp32) can however be used here as well. This tool is significantly faster and makeEspArduino will check if "esptool.py" can be found in the path. When present, it will be used for the flashing. An alternative location outside of the path for "esptool.py" can also be specified via the variable ESPTOOL. This tool is not part of ESP/Arduino and subsequently must be installed separately from: https://github.com/espressif/esptool or just by typing:

pip install esptool

For esp32 this tool is included and used for all flashing operations by default.

Building a file system

There are also rules in the makefile which can be used for building and uploading a complete SPIFFS file system to the ESP. This is basically the same functionality as the one available in the Arduino IDE, https://github.com/esp8266/Arduino/blob/master/doc/filesystem.rst#uploading-files-to-file-system

The bundled tool "mkspiffs" is used for this.

The size and flash location parameters are taken from boards.txt for esp8266 and from the partition table for esp32.

The file system content is made up of everything within a directory specified via the variable FS_DIR. By default this variable is set to a subdirectory named data in the sketch directory.

Use the rule flash_fs or ota_fs to generate a file system image and upload it to the ESP.

All the settings for the file system are taken from the selected board's configuration.

It is also possible to dump and recreate the complete file system from the device via the rule dump_fs. The corresponding flash section will be extracted and the individual files recreated in a directory in the build structure.

Please note for esp32!

Version 0.2.2 or later of mkspiffs is required.

Additional flash I/O operations

The makefile has rules for dumping and restoring the whole flash memory contents to and from a file. This can be convenient for saving a specific state or software for which no source code is available.

For esp8266, this functionality requires that "esptool.py" is available as specified above.

The rules are named dump_flash and restore_flash. The name of the output/input file is controlled by the variable FLASH_FILE. The default value for this is "esp_flash.bin". All required parameters for the operations are taken from the variables mentioned above for flash size, serial port and speed etc.


espmake dump_flash FLASH_FILE=my_flash.bin

Building an object file library

It is also possible to build a library containing all the object files referenced in the build (excluding the sketch itself). This can e.g. be used to build separately compiled version controlled libraries which are then used in other build projects.


espmake lib