This is the documentation for the latest (main) development branch of Zephyr. If you are looking for the documentation of previous releases, use the drop-down menu on the left and select the desired version.

HelTec Wireless Stick Lite (V3)

Overview

HelTec Wireless Stick Lite (V3) is a development board with Wi-Fi, Bluetooth and LoRa support. It is designed and produced by HelTec Automation(TM). [1]

HelTec Wireless Stick Lite (V3)

HelTec Wireless Stick Lite (V3) (Credit: Chengdu HelTec Automation Technology Co., Ltd.)

Hardware

The main hardware features are:

  • ESP32-S3FN8 low-power MCU-based SoC (dual-core Xtensa® 32-bit LX7 microprocessor, five stage pipeline rack Structure, main frequency up to 240 MHz).

  • Semtech SX1262 LoRa node chip

  • Type-C USB interface with a complete voltage regulator, ESD protection, short circuit protection, RF shielding, and other protection measures (note: you need an USB-A to USB-C cable if you want to power-up the board from USB).

  • Onboard SH1.25-2 battery interface, integrated lithium battery management system (charge and discharge management, overcharge protection, battery power detection, USB / battery power automatic switching).

  • Integrated WiFi and Bluetooth interfaces with 2.4GHz metal spring antenna and reserved IPEX (U.FL) interface for LoRa use.

  • Integrated CP2102 USB to serial port chip, convenient for program downloading, debugging information printing.

  • Good RF circuit design and low-power design.

Supported Features

  • LoRa via SPI

  • UART0 (USB Serial via CP2102)

  • UART1

  • I2C

  • CAN (optional, need to enable)

  • PWM LED

  • User Switch / Button

Connections and IOs

HelTec Wireless Stick Lite (V3) Pinout

Pinout (Credit: Chengdu HelTec Automation Technology Co., Ltd.)

HelTec Wireless Stick Lite (V3) Pinout

Header

Function

Description

J2.1

Ve

J2.2

GND

J2.3

J2.4

U0RXD

Zephyr Console+Shell

J2.5

U0TXD

Zephyr Console+Shell

J2.6

J2.7

J2.8

GPIO35

PWM LED Control

J2.9

GPIO36

Vext Control

J2.10

GPIO37

ADC Control

J2.11

J2.12

GPIO39

J2.13

GPIO40

J2.14

GPIO41

J2.15

GPIO42

J2.16

GPIO45

J2.17

GPIO46

J2.18

ADC1_CH0

Battery Voltage Measurement

J2.19

J2.20

J3.1

5V

J3.2

3V3

J3.3

GND

J3.4

GPIO47

J3.5

GPIO48

J3.6

GPIO0

User Switch

J3.7

J3.8

J3.9

U1RXD

UART 1

J3.10

GPIO21

J3.11

J3.12

U1TXD

UART 1

J3.13

J3.14

NC

Reset Switch

J3.15

J3.16

J3.17

J3.18

J3.19

TWAI_TX

CAN (optional)

J3.20

TWAI_RX

CAN (optional)

System requirements

Prerequisites

Espressif HAL requires WiFi and Bluetooth binary blobs in order work. Run the command below to retrieve those files.

west blobs fetch hal_espressif

Note

It is recommended running the command above after west update.

Programming and Debugging

ESP-IDF bootloader

The board is using the ESP-IDF bootloader as the default 2nd stage bootloader. It is build as a subproject at each application build. No further attention is expected from the user.

MCUboot bootloader

User may choose to use MCUboot bootloader instead. In that case the bootloader must be build (and flash) at least once.

There are two options to be used when building an application:

  1. Sysbuild

  2. Manual build

Note

User can select the MCUboot bootloader by adding the following line to the board default configuration file. ` CONFIG_BOOTLOADER_MCUBOOT=y `

Sysbuild

The sysbuild makes possible to build and flash all necessary images needed to bootstrap the board with the EPS32-S3 SoC.

To build the sample application using sysbuild use the command:

west build -b heltec_wireless_stick_lite_v3 --sysbuild samples/hello_world

By default, the ESP32S3 sysbuild creates bootloader (MCUboot) and application images. But it can be configured to create other kind of images.

Build directory structure created by sysbuild is different from traditional Zephyr build. Output is structured by the domain subdirectories:

build/
├── hello_world
│   └── zephyr
│       ├── zephyr.elf
│       └── zephyr.bin
├── mcuboot
│    └── zephyr
│       ├── zephyr.elf
│       └── zephyr.bin
└── domains.yaml

Note

With --sysbuild option the bootloader will be re-build and re-flash every time the pristine build is used.

For more information about the system build please read the Sysbuild (System build) documentation.

Manual build

During the development cycle, it is intended to build & flash as quickly possible. For that reason, images can be build one at a time using traditional build.

The instructions following are relevant for both manual build and sysbuild. The only difference is the structure of the build directory.

Note

Remember that bootloader (MCUboot) needs to be flash at least once.

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_wireless_stick_lite_v3 samples/hello_world

The usual flash target will work with the heltec_wireless_stick_lite_v3 board configuration. Here is an example for the Hello World application.

# From the root of the zephyr repository
west build -b heltec_wireless_stick_lite_v3 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_wireless_stick_lite_v3

Debugging

As with much custom hardware, the ESP32S3 modules require patches to OpenOCD that are not upstreamed yet. Espressif maintains their own fork of the project. The custom OpenOCD can be obtained at OpenOCD ESP32

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_wireless_stick_lite_v3 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_wireless_stick_lite_v3 samples/hello_world
west debug

References