209 lines
6.3 KiB
ReStructuredText
209 lines
6.3 KiB
ReStructuredText
.. _heltec_wifi_lora32_v2:
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Heltec WiFi LoRa 32 (V2)
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########################
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Overview
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********
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Heltec WiFi LoRa 32 is a classic IoT dev-board designed & produced by Heltec Automation(TM), it's a highly
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integrated product based on ESP32 + SX127x, it has Wi-Fi, BLE, LoRa functions, also Li-Po battery management
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system, 0.96" OLED are also included. [1]_
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The features include the following:
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- Microprocessor: ESP32 (dual-core 32-bit MCU + ULP core)
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- LoRa node chip SX1276/SX1278
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- Micro USB interface with a complete voltage regulator, ESD protection, short circuit protection,
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RF shielding, and other protection measures
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- Onboard SH1.25-2 battery interface, integrated lithium battery management system
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- Integrated WiFi, LoRa, Bluetooth three network connections, onboard Wi-Fi, Bluetooth dedicated 2.4GHz
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metal 3D antenna, reserved IPEX (U.FL) interface for LoRa use
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- Onboard 0.96-inch 128*64 dot matrix OLED display
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- Integrated CP2102 USB to serial port chip
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System requirements
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*******************
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Prerequisites
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=============
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Espressif HAL requires WiFi and Bluetooth binary blobs in order work. Run the command
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below to retrieve those files.
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.. code-block:: console
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west blobs fetch hal_espressif
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.. note::
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It is recommended running the command above after :file:`west update`.
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Building & Flashing
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*******************
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ESP-IDF bootloader
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==================
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The board is using the ESP-IDF bootloader as the default 2nd stage bootloader.
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It is build as a subproject at each application build. No further attention
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is expected from the user.
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MCUboot bootloader
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==================
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User may choose to use MCUboot bootloader instead. In that case the bootloader
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must be build (and flash) at least once.
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There are two options to be used when building an application:
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1. Sysbuild
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2. Manual build
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.. note::
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User can select the MCUboot bootloader by adding the following line
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to the board default configuration file.
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```
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CONFIG_BOOTLOADER_MCUBOOT=y
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```
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Sysbuild
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========
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The sysbuild makes possible to build and flash all necessary images needed to
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bootstrap the board with the ESP32 SoC.
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To build the sample application using sysbuild use the command:
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.. zephyr-app-commands::
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:tool: west
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:app: samples/hello_world
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:board: heltec_wifi_lora32_v2
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:goals: build
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:west-args: --sysbuild
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:compact:
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By default, the ESP32 sysbuild creates bootloader (MCUboot) and application
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images. But it can be configured to create other kind of images.
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Build directory structure created by sysbuild is different from traditional
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Zephyr build. Output is structured by the domain subdirectories:
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.. code-block::
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build/
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├── hello_world
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│ └── zephyr
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│ ├── zephyr.elf
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│ └── zephyr.bin
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├── mcuboot
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│ └── zephyr
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│ ├── zephyr.elf
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│ └── zephyr.bin
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└── domains.yaml
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.. note::
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With ``--sysbuild`` option the bootloader will be re-build and re-flash
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every time the pristine build is used.
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For more information about the system build please read the :ref:`sysbuild` documentation.
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Manual build
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============
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During the development cycle, it is intended to build & flash as quickly possible.
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For that reason, images can be build one at a time using traditional build.
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The instructions following are relevant for both manual build and sysbuild.
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The only difference is the structure of the build directory.
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.. note::
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Remember that bootloader (MCUboot) needs to be flash at least once.
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Build and flash applications as usual (see :ref:`build_an_application` and
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:ref:`application_run` for more details).
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.. zephyr-app-commands::
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:zephyr-app: samples/hello_world
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:board: heltec_wifi_lora32_v2
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:goals: build
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The usual ``flash`` target will work with the ``heltec_wifi_lora32_v2`` board
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configuration. Here is an example for the :ref:`hello_world`
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application.
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.. zephyr-app-commands::
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:zephyr-app: samples/hello_world
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:board: heltec_wifi_lora32_v2
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:goals: flash
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Open the serial monitor using the following command:
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.. code-block:: shell
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west espressif monitor
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After the board has automatically reset and booted, you should see the following
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message in the monitor:
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.. code-block:: console
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***** Booting Zephyr OS vx.x.x-xxx-gxxxxxxxxxxxx *****
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Hello World! heltec_wifi_lora32_v2
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Debugging
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*********
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As with much custom hardware, the ESP32 modules require patches to
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OpenOCD that are not upstreamed yet. Espressif maintains their own fork of
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the project. The custom OpenOCD can be obtained at `OpenOCD ESP32`_
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The Zephyr SDK uses a bundled version of OpenOCD by default. You can overwrite that behavior by adding the
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``-DOPENOCD=<path/to/bin/openocd> -DOPENOCD_DEFAULT_PATH=<path/to/openocd/share/openocd/scripts>``
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parameter when building.
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Here is an example for building the :ref:`hello_world` application.
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.. zephyr-app-commands::
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:zephyr-app: samples/hello_world
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:board: heltec_wifi_lora32_v2
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:goals: build flash
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:gen-args: -DOPENOCD=<path/to/bin/openocd> -DOPENOCD_DEFAULT_PATH=<path/to/openocd/share/openocd/scripts>
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You can debug an application in the usual way. Here is an example for the :ref:`hello_world` application.
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.. zephyr-app-commands::
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:zephyr-app: samples/hello_world
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:board: heltec_wifi_lora32_v2
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:goals: debug
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Utilizing Hardware Features
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***************************
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Onboard OLED display
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====================
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The onboard OLED display is of type ``ssd1306``, has 128*64 pixels and is
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connected via I2C. It can therefore be used by enabling the
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:ref:`ssd1306_128_shield` as shown in the following for the :zephyr:code-sample:`lvgl` sample:
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.. zephyr-app-commands::
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:zephyr-app: samples/subsys/display/lvgl
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:board: heltec_wifi_lora32_v2
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:shield: ssd1306_128x64
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:goals: flash
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References
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**********
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- `Heltec WiFi LoRa (v2) Pinout Diagram <https://resource.heltec.cn/download/WiFi_LoRa_32/WIFI_LoRa_32_V2.pdf>`_
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- `Heltec WiFi LoRa (v2) Schematic Diagrams <https://resource.heltec.cn/download/WiFi_LoRa_32/V2>`_
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- `ESP32 Toolchain <https://docs.espressif.com/projects/esp-idf/en/v4.2/esp32/api-guides/tools/idf-tools.html#xtensa-esp32-elf>`_
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- `esptool documentation <https://github.com/espressif/esptool/blob/master/README.md>`_
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- `OpenOCD ESP32 <https://github.com/espressif/openocd-esp32/releases>`_
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.. [1] https://heltec.org/project/wifi-lora-32/
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