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Heltec WiFi LoRa 32 (V2)

Overview

Heltec WiFi LoRa 32 is a classic IoT dev-board designed & produced by Heltec Automation(TM), it’s a highly integrated product based on ESP32 + SX127x, it has Wi-Fi, BLE, LoRa functions, also Li-Po battery management system, 0.96” OLED are also included. 1

The features include the following:

  • Microprocessor: ESP32 (dual-core 32-bit MCU + ULP core)

  • LoRa node chip SX1276/SX1278

  • Micro USB interface with a complete voltage regulator, ESD protection, short circuit protection, RF shielding, and other protection measures

  • Onboard SH1.25-2 battery interface, integrated lithium battery management system

  • Integrated WiFi, LoRa, Bluetooth three network connections, onboard Wi-Fi, Bluetooth dedicated 2.4GHz

    metal 3D antenna, reserved IPEX (U.FL) interface for LoRa use

  • Onboard 0.96-inch 128*64 dot matrix OLED display

  • Integrated CP2102 USB to serial port chip

System requirements

Prerequisites

Espressif HAL requires binary blobs in order work. The west extension below performs the required syncronization to clone, checkout and pull the submodules:

west espressif update

Note

It is recommended running the command above after west update.

Building & Flashing

Build and flash applications as usual (see Building an Application and Run an Application for more details).

# From the root of the zephyr repository
west build -b heltec_wifi_lora32_v2 samples/hello_world

The usual flash target will work with the heltec_wifi_lora32_v2 board configuration. Here is an example for the Hello World application.

# From the root of the zephyr repository
west build -b heltec_wifi_lora32_v2 samples/hello_world
west flash

Open the serial monitor using the following command:

west espressif monitor

After the board has automatically reset and booted, you should see the following message in the monitor:

***** Booting Zephyr OS vx.x.x-xxx-gxxxxxxxxxxxx *****
Hello World! heltec_wifi_lora32_v2

Debugging

As with much custom hardware, the ESP32 modules require patches to OpenOCD that are not upstreamed. Espressif maintains their own fork of the project. The custom OpenOCD can be obtained by running the following extension:

west espressif install

Note

By default, the OpenOCD will be downloaded and installed under $HOME/.espressif/tools/zephyr directory (%USERPROFILE%/.espressif/tools/zephyr on Windows).

The Zephyr SDK uses a bundled version of OpenOCD by default. You can overwrite that behavior by adding the -DOPENOCD=<path/to/bin/openocd> -DOPENOCD_DEFAULT_PATH=<path/to/openocd/share/openocd/scripts> parameter when building.

Here is an example for building the Hello World application.

# From the root of the zephyr repository
west build -b heltec_wifi_lora32_v2 samples/hello_world -- -DOPENOCD=<path/to/bin/openocd> -DOPENOCD_DEFAULT_PATH=<path/to/openocd/share/openocd/scripts>
west flash

You can debug an application in the usual way. Here is an example for the Hello World application.

# From the root of the zephyr repository
west build -b heltec_wifi_lora32_v2 samples/hello_world
west debug