Build and Flash with Make

Finding a project

As well as the esp-idf-template project mentioned in the setup guide, esp-idf comes with some example projects on github in the examples directory.

Once you’ve found the project you want to work with, change to its directory and you can configure and build it:

Configuring your project

make menuconfig

Compiling your project

make all

... will compile app, bootloader and generate a partition table based on the config.

Flashing your project

When make all finishes, it will print a command line to use esptool.py to flash the chip. However you can also do this from make by running:

make flash

This will flash the entire project (app, bootloader and partition table) to a new chip. The settings for serial port flashing can be configured with make menuconfig.

You don’t need to run make all before running make flash, make flash will automatically rebuild anything which needs it.

Compiling & Flashing Just the App

After the initial flash, you may just want to build and flash just your app, not the bootloader and partition table:

  • make app - build just the app.
  • make app-flash - flash just the app.

make app-flash will automatically rebuild the app if it needs it.

(There’s no downside to reflashing the bootloader and partition table each time, if they haven’t changed.)

The Partition Table

Once you’ve compiled your project, the “build” directory will contain a binary file with a name like “my_app.bin”. This is an ESP32 image binary that can be loaded by the bootloader.

A single ESP32’s flash can contain multiple apps, as well as many different kinds of data (calibration data, filesystems, parameter storage, etc). For this reason a partition table is flashed to offset 0x4000 in the flash.

Each entry in the partition table has a name (label), type (app, data, or something else), subtype and the offset in flash where the partition is loaded.

The simplest way to use the partition table is to make menuconfig and choose one of the simple predefined partition tables:

  • “Single factory app, no OTA”
  • “Factory app, two OTA definitions”

In both cases the factory app is flashed at offset 0x10000. If you make partition_table then it will print a summary of the partition table.

For more details about partition tables and how to create custom variations, view the documentation.