Build the Project

Build the project by running:

idf.py build

This command compiles the application and all ESP-IDF components, then it generates the bootloader, partition table, and application binaries.

$ idf.py build
Running cmake in directory /path/to/hello_world/build
Executing "cmake -G Ninja --warn-uninitialized /path/to/hello_world"...
Warn about uninitialized values.
-- Found Git: /usr/bin/git (found version "2.17.0")
-- Building empty aws_iot component due to configuration
-- Component names: ...
-- Component paths: ...

... (more lines of build system output)

[527/527] Generating hello_world.bin
esptool v5.0.2

Project build complete. To flash, run:
  idf.py flash
or
  idf.py -p PORT flash
or
  esptool -p (PORT) -b 921600 write-flash --flash-mode dio --flash-size detect --flash-freq 40m 0x10000 build/hello_world.bin  build 0x1000 build/bootloader/bootloader.bin 0x8000 build/partition_table/partition-table.bin

If there are no errors, the build finishes by generating the firmware binary .bin files.

Flash onto the Device

To flash the binaries that you just built for the ESP32 in the previous step, you need to run the following command:

idf.py -p PORT flash

Replace PORT with your ESP32 board's USB port name. If the PORT is not defined, the idf.py will try to connect automatically using the available USB ports.

For more information on idf.py arguments, see idf.py.

Note

The option flash automatically builds and flashes the project, so running idf.py build is not necessary.

Encountered Issues While Flashing? See the "Additional Tips" below. You can also refer to Flashing Troubleshooting page or Establish Serial Connection with ESP32 for more detailed information.

Normal Operation

When flashing, you will see the output log similar to the following:

...
esptool --chip esp32 -p /dev/ttyUSB0 -b 460800 --before=default-reset --after=hard-reset write-flash --flash-mode dio --flash-freq 40m --flash-size 2MB 0x8000 partition_table/partition-table.bin 0x1000 bootloader/bootloader.bin 0x10000 hello_world.bin
esptool v5.0.2
Connected to ESP32 on /dev/ttyUSB0:
Chip type:          ESP32-U4WDH (revision v3.0)
Features:           Wi-Fi, BT, Dual Core + LP Core, 240MHz, Embedded Flash, Vref calibration in eFuse, Coding Scheme None
Crystal frequency:  40MHz
MAC:                24:0a:c4:05:b9:14

Stub flasher running.
Changing baud rate to 460800...
Changed.

Configuring flash size...
Flash will be erased from 0x00008000 to 0x00008fff...
Flash will be erased from 0x00001000 to 0x00007fff...
Flash will be erased from 0x00010000 to 0x00031fff...
Wrote 3072 bytes (103 compressed) at 0x00008000 in 0.1 seconds (279.3 kbit/s).
Hash of data verified.
SHA digest in image updated.
Wrote 26352 bytes (16660 compressed) at 0x00001000 in 0.9 seconds (239.3 kbit/s).
Hash of data verified.
Wrote 137312 bytes (78774 compressed) at 0x00010000 in 2.2 seconds (490.8 kbit/s).
Hash of data verified.

Hard resetting via RTS pin...

If there are no issues by the end of the flash process, the board will reboot and start up the "hello_world" application.

If you would like to use the Eclipse or VS Code IDE instead of running idf.py, check out Eclipse Plugin, VSCode Extension.

Monitor the Output

To check if "hello_world" is indeed running, type idf.py -p PORT monitor (Do not forget to replace PORT with your serial port name).

This command launches the IDF Monitor application.

$ idf.py -p <PORT> monitor
Running idf_monitor in directory [...]/esp/hello_world/build
Executing "python [...]/esp-idf/tools/idf_monitor.py -b 115200 [...]/esp/hello_world/build/hello_world.elf"...
--- idf_monitor on <PORT> 115200 ---
--- Quit: Ctrl+] | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---
ets Jun  8 2016 00:22:57

rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
ets Jun  8 2016 00:22:57
...

After startup and diagnostic logs scroll up, you should see "Hello world!" printed out by the application.

    ...
    Hello world!
    Restarting in 10 seconds...
    This is esp32 chip with 2 CPU core(s), WiFi/BT/BLE, silicon revision 1, 2 MB external flash
Minimum free heap size: 298968 bytes
    Restarting in 9 seconds...
    Restarting in 8 seconds...
    Restarting in 7 seconds...

To exit IDF monitor use the shortcut Ctrl+].

If IDF monitor fails shortly after the upload, or, if instead of the messages above, you see random garbage similar to what is given below, your board is likely using a 26 MHz crystal. Most development board designs use 40 MHz, so ESP-IDF uses this frequency as a default value.

Garbled output

If you have such a problem, do the following:

  1. Exit the monitor.

  2. Go back to menuconfig.

  3. Go to Component config --> Hardware Settings --> Main XTAL Config --> Main XTAL frequency, then change CONFIG_XTAL_FREQ to 26 MHz.

  4. After that, build and flash the application again.

In the current version of ESP-IDF, main XTAL frequencies supported by ESP32 are as follows:

  • 26 MHz

  • 40 MHz

Note

You can combine building, flashing and monitoring into one step by running:

idf.py -p PORT flash monitor

See also:

  • IDF Monitor for handy shortcuts and more details on using IDF monitor.

  • idf.py for a full reference of idf.py commands and options.

That is all that you need to get started with ESP32!

Now you are ready to try some other examples, or go straight to developing your own applications.

Important

Some of examples do not support ESP32 because required hardware is not included in ESP32 so it cannot be supported.

If building an example, please check the README file for the Supported Targets table. If this is present including ESP32 target, or the table does not exist at all, the example will work on ESP32.

Additional Tips

Permission Denied Issue

With some Linux distributions, you may get the error message similar to Could not open port <PORT>: Permission denied: '<PORT>' when flashing the ESP32. This can be solved by adding the current user to the specific group, such as dialout or uucp group.

Python Compatibility

ESP-IDF supports Python 3.10 or newer. It is recommended to upgrade your operating system to a recent version satisfying this requirement. Other options include the installation of Python from sources or the use of a Python version management system such as pyenv.

Start with Board Support Package

To speed up prototyping on some development boards, you can use Board Support Packages (BSPs), which makes initialization of a particular board as easy as few function calls.

A BSP typically supports all of the hardware components provided on development board. Apart from the pinout definition and initialization functions, a BSP ships with drivers for the external components such as sensors, displays, audio codecs etc.

The BSPs are distributed via IDF Component Manager, so they can be found in ESP Component Registry.

Here is an example of how to add ESP-WROVER-KIT BSP to your project:

idf.py add-dependency esp_wrover_kit

More examples of BSP usage can be found in BSP examples folder.

Flash Erase

Erasing the flash is also possible. To erase the entire flash memory you can run the following command:

idf.py -p PORT erase-flash

For erasing the OTA data, if present, you can run this command:

idf.py -p PORT erase-otadata

The flash erase command can take a while to be done. Do not disconnect your device while the flash erasing is in progress.

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