Lilygo TTGO LoRa32
Overview
The Lilygo TTGO LoRa32 is a development board for LoRa applications baesed on the ESP32-PICO-D4.
It’s available in two versions supporting two different frequency ranges and features the following integrated components:
ESP32-PICO-D4 chip (240MHz dual core, 600 DMIPS, 520KB SRAM, Wi-Fi)
SSD1306, 128x64 px, 0.96” screen
SX1278 (433MHz) or SX1276 (868/915/923MHz) LoRa radio frontend
JST GH 2-pin battery connector
TF card slot
Some of the ESP32 I/O pins are accessible on the board’s pin headers.
Lilygo TTGO LoRa32 module
Functional Description
The following table below describes the key components, interfaces, and controls of the Lilygo TTGO LoRa32 board.
Key Component |
Description |
|---|---|
ESP32-PICO-D4 |
This ESP32-PICO-D4 module provides complete Wi-Fi and Bluetooth functionalities and integrates a 4-MB SPI flash. |
Diagnostic LED |
One user LED connected to the GPIO pin. |
USB Port |
USB interface. Power supply for the board as well as the serial communication interface between a computer and the board. Micro-USB type connector. |
Power Switch |
Sliding power switch. |
LCD screen |
Built-in OLED display (SSD1306, 0.96”, 128x64 px) controlled by I2C interface |
SX1276/SX1278 |
LoRa radio frontend chip, connected via SPI. Use SX1276 for 433MHz and SX1276 for 868/915/923MHz. |
TF card slot |
TF card slot wired to the SD interface of the MCU. |
Start Application Development
Before powering up your Lilygo TTGO LoRa32, please make sure that the board is in good condition with no obvious signs of damage.
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.
Building & Flashing
Simple boot
The board could be loaded using the single binary image, without 2nd stage bootloader. It is the default option when building the application without additional configuration.
Note
Simple boot does not provide any security features nor OTA updates.
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:
Sysbuild
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 ESP32-PICO-D4 SoC.
To build the sample application using sysbuild use the command:
west build -b ttgo_lora32/esp32/procpu --sysbuild samples/hello_world
By default, the ESP32-PICO-D4 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 ttgo_lora32/esp32/procpu samples/hello_world
The usual flash target will work with the ttgo_lora32 board
configuration. Here is an example for the Hello World
application.
# From the root of the zephyr repository
west build -b ttgo_lora32/esp32/procpu samples/hello_world
west flash
The default baud rate for the Lilygo TTGO LoRa32 is set to 1500000bps. If experiencing issues when flashing,
try using different values by using --esp-baud-rate <BAUD> option during
west flash (e.g. west flash --esp-baud-rate 115200).
You can also 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! ttgo_lora32
LoRa samples
There are two LoRa samples that will work out of the box with this board.
To build the LoRa transmit sample application using sysbuild use the command:
west build -b ttgo_lora32/esp32/procpu --sysbuild samples/drivers/lora/send
To build the LoRa receive sample application using sysbuild use the command:
west build -b ttgo_lora32/esp32/procpu --sysbuild samples/drivers/lora/receive
Debugging
Lilygo TTGO LoRa32 debugging is not supported due to pinout limitations.