2. May 2023

How to build single flashable binary for ESP32 with esptool.py

Build of ESP-IDF project produces several files, like bootloader, application binary or partition table.

Having several files makes it harder to ship the application outside of build computer.

Solution to the problem is merging binaries into single flashable file.

Build your project with idf.py as always:

cd project
idf.py build

Merge binaries into single file. At the end of build process the tool will display command for flashing. This can be used to compose command like this:

esptool.py --chip ESP32 merge_bin -o merged-flash.bin --flash_mode dio ^
  --flash_size ^
  2MB 0x0 build\bootloader\bootloader.bin ^
  0x8000 build\partition_table\partition-table.bin ^
  0x10000 build\my_app.bin

Luckily there is a simpler way, because all those arguments are stored in build/flash_args file:

Example for Bash

(cd build; esptool.py --chip esp32 merge_bin -o merged-flash.bin @flash_args)

Example for PowerShell

cd build
esptool.py --chip esp32 merge_bin -o merged-flash.bin "@flash_args"

17. April 2023

Matter: chip-tool pairing ble-wifi failing with Abort trap: 6 on macOS

chip-tool can be used for commissioning ESP32 with Matter.

macOS users may face the following error with iTerm:

chip-tool interactive start

pairing ble-wifi 0x7283 SSID PASS PIN 3840
..[FP] Validating NOC chain
..[FP] NOC chain validation successful
..[FP] Added new fabric at index: 0x1
...
Abort trap: 6

It’s necessary to grant access to Bluetooth to apps launched from iTerm.

Click System SettingsPrivacy & Security. Select Bluetooth. Click +, Select Applications, and find iTerm.

Close and open iTerm. The problem with “trap 6” should be gone.

Just do not forget to install Bluetooth Central Matter Client Developer mode profile. Otherwise the provisioning will fail with UUID problem.

14. April 2023

Setting up esp-matter development environtment on openSUSE

When setting up development environment for esp-matter on OpenSUSE you may encouter following error:

./install.sh
...
Error
uilding wheels for collected packages: gevent
  Building wheel for gevent (pyproject.toml): started
  error: subprocess-exited-with-error
  
  × Building wheel for gevent (pyproject.toml) did not run successfully.
  │ exit code: 1
  ╰─> See above for output.
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
  Building wheel for gevent (pyproject.toml): finished with status 'error'
  ERROR: Failed building wheel for gevent
Failed to build gevent
ERROR: Could not build wheels for gevent, which is required to install pyproject.toml-based projects
['esp-matter/connectedhomeip/connectedhomeip/.environment/pigweed-venv/bin/python', '-m', 'pip', 'install', '--log', 'esp-matter/connectedhomeip/connectedhomeip/.environment/pigweed-venv/pip-requirements.log', '--requirement=esp-matter/connectedhomeip/connectedhomeip/scripts/setup/requirements.txt', '--constraint=esp-matter/connectedhomeip/connectedhomeip/scripts/setup/constraints.txt'] {'stdout': <_io.TextIOWrapper name=3 mode='w+' encoding='UTF-8'>, 'stderr': -2}

Problem is caused by gdbgui dependency in ESP-IDF. The dependency is not necessary to build the project.

Edit file esp-matter/connectedhomeip/connectedhomeip/scripts/setup/requirements.esp32.txt .

Disable the line with gdbgui:

#gdbgui==0.13.2.0 ; platform_machine != 'aarch64' and sys_platform == 'linux'

Continue with `./install.sh` script.

21. December 2022

Rust Bare Metal application for ESP32, desktop, Android and iOS

Rust language and tooling are very powerful. It makes it easy to build for different platforms and architectures and still have performance close to C language.

It’s possible to write the same application for ESP32 with Xtensa architecture or ESP32-C3 RISC-V architecture. The portability of Rust code is high. Changing the target and adding a few wrapper functions makes it possible to build the same application for the desktop or web browser with WebAssembly. Once the WebAssembly is ready, it’s possible to turn the application into Progressive Web App (PWA) which can be installed on Android or iOS.

ESP32 Spooky Maze game is example of application which can work on ESP32 and also on mobile device. The shared core code contains the main part of the implementation, and each platform has its tiny wrapper.

The example Rust application uses Embedded Graphics to draw images. When the app is running on real HW, it’s transferred to the display via SPI using ESP-HAL. The desktop version is using SDL2 to interact with Linux, macOS, or Windows. The web version is using WASM, and framebuffer is serialized to HTML5 canvas. PWA application for Android also supports access to Accelerometer, so it can simulate similar behavior like IMU on ESP32-C3-DevKit-RUST or ESP32-S3-BOX where user can tilt the device to move the character in the maze.

Web version of the application with PWA support: Spooky (full-screen mode)

Embedded version of the application: ESP32-S3-BOX, M5CORE-FIRE (M5Stack) and many more.

Thanks to cloud development IDEs, it’s possible to build the application on GitPod.io or GitHub Codespaces and run it even without real HW using Wokwi simulator.

30. August 2022

Unable to flash ESP32 (S2, S3, C3) with these USB-C cables

USB-C is becoming more and more popular. A straightforward assumption is that you can replace the old cable with a USB-A connector with USB-C, and everything should be the same. This assumption is wrong.

Some cables do not work well with ESP32, S2, S3, and C3. Here you can find information about cables which does not work and it’s not possible to flash dev boards with the chip with espflash, idf.py or esptool.py.

A typical error message looks like this:

Serial port: /dev/tty.usbserial-110
Connecting...

Unable to connect, retrying with extra delay...
Unable to connect, retrying with default delay...
Unable to connect, retrying with extra delay...
Error: espflash::connection_failed

  × Error while connecting to device
  ╰─▶ Failed to connect to the device
  help: Ensure that the device is connected and the reset and boot pins are not being held down

USB-C to micro-USB connected to boards ESP32-S2-USB-OTG and ESP32-S3-USB-OTG, length 60 cm, marks on cable “AWM 80 C 30V VW-1 USB 2.0 CABLE”:

  • directly connected to mac M1 2020 – does not work
  • workaround #1: press and hold boot button on the board, start flash command, release boot button after flashing process starts
  • workaround #2: connect mac M1 to monitor/hub with USB-C and connect the cable there
  • workaround #3: use computer with Windows or Linux, the cable seems to work correctly with these OSes