T-Watch Ultra Quick Start

Dependencies

Library	Version	Source
Arduino-ESP32	3.3.0-alpha1 or later	Installation guide
LilyGoLib	Current master	GitHub
LVGL	9.4.0	LilyGoLib-ThirdParty
RadioLib	7.4.0	LilyGoLib-ThirdParty
XPowersLib	0.3.1	LilyGoLib-ThirdParty

LilyGoLib-ThirdParty contains the tested dependency versions. Do not upgrade those libraries until the helloworld example runs correctly. See the complete T-Watch Ultra dependency list.

Arduino

PlatformIO

The main LilyGoLib repository uses Arduino-ESP32 3.x, which PlatformIO does not currently support for this device. Use the separate LilyGoLib-PlatformIO repository, which uses Arduino-ESP32 2.0.17 (ESP-IDF 4.4.7):

Install VS Code and the PlatformIO IDE extension.

Clone the PlatformIO repository:

bash

git clone https://github.com/Xinyuan-LilyGO/LilyGoLib-PlatformIO.git

Follow that repository's environment instructions for T-Watch Ultra.

Arduino IDE

Board Settings

Setting	Value
Board	LilyGo T-Watch-Ultra
Port	Device port
Upload Speed	921600
Upload Mode	UART0 / Hardware CDC
USB Mode	Hardware CDC and JTAG
USB CDC On Boot	Enabled
USB Firmware MSC On Boot	Disabled
USB DFU On Boot	Disabled
CPU Frequency	240 MHz (WiFi)
Core Debug Level	None
Erase All Flash Before Sketch Upload	Disabled
JTAG Adapter	Disabled
Arduino Runs On	Core 1
Events Run On	Core 1
Partition Scheme	16M Flash (3MB APP/9.9MB FATFS)
Board Revision	Radio-SX1262 (select the installed radio)

Board Revision options:

Radio-SX1262: Sub-GHz LoRa
Radio-SX1280: 2.4 GHz LoRa
Radio-CC1101: Sub-GHz (G)MSK, (G)FSK, ASK, and OOK
Radio-LR1121: Sub-GHz and 2.4 GHz LoRa
Radio-SI4432: Sub-GHz ISM

The dedicated board definition automatically configures 16 MB QSPI Flash and 8 MB QSPI PSRAM. Do not select ESP32S3 Dev Module.

Steps

Install Arduino IDE.
Add https://espressif.github.io/arduino-esp32/package_esp32_dev_index.json to Additional Boards Manager URLs, then install Arduino-ESP32 3.3.0-alpha1 or later.
Download LilyGoLib, then select Sketch → Include Library → Add .ZIP Library.
Download LilyGoLib-ThirdParty and copy the folders inside it to the Arduino libraries directory. Do not copy only the outer repository folder.
Open File → Examples → LilyGoLib → helloworld.
Apply the board settings above, select the port, and click Upload.

If there is no serial output, verify that USB CDC On Boot is Enabled.

LVGL

T-Watch Ultra uses LVGL 9.4.0 through LilyGoLib. The library handles AMOLED initialization, touch input, and display flushing.

Hello World

cpp

#include <LilyGoLib.h>
#include <LV_Helper.h>

void setup() {
    instance.begin();
    beginLvglHelper(instance);

    lv_obj_t *label = lv_label_create(lv_screen_active());
    lv_label_set_text(label, "T-Watch Ultra");
    lv_obj_align(label, LV_ALIGN_CENTER, 0, 0);
}

void loop() {
    lv_timer_handler();
    delay(2);
}

Peripheral Examples

Display (AMOLED — LilyGoLib)

cpp

#include <LilyGoLib.h>

void setup() {
    instance.begin();
    instance.setBrightness(200);
    // Fill screen red
    uint16_t w = instance.width(), h = instance.height();
    uint16_t *buf = (uint16_t *)ps_malloc(w * h * 2);
    if (buf) {
        for (int i = 0; i < w * h; i++) buf[i] = 0xF800;
        instance.pushColors(0, 0, w - 1, h - 1, buf);
        free(buf);
    }
}

void loop() {}

Touch

cpp

#include <LilyGoLib.h>

void setup() {
    instance.begin();
}

void loop() {
    int16_t x, y;
    if (instance.getPoint(&x, &y, 1)) {
        Serial.printf("Touch X=%d Y=%d\n", x, y);
    }
    delay(10);
}

LoRa (SX1262 — RadioLib)

cpp

#include <LilyGoLib.h>

void setup() {
    Serial.begin(115200);
    instance.begin(); // Initializes the selected radio and its power rail
    radio.setFrequency(915.0);
}

void loop() {
    radio.transmit("Hello T-Watch Ultra");
    delay(2000);
}

GPS (MIA-M10Q — TinyGPSPlus)

cpp

#include <LilyGoLib.h>

void setup() {
    Serial.begin(115200);
    instance.begin(); // Initializes MIA-M10Q on Serial1 (RX=44, TX=43)
}

void loop() {
    while (Serial1.available()) instance.gps.encode(Serial1.read());
    if (instance.gps.location.isUpdated()) {
        Serial.printf("Lat: %.6f  Lon: %.6f\n",
                      instance.gps.location.lat(), instance.gps.location.lng());
    }
}

PMU (AXP2101 — LilyGoLib)

cpp

#include <LilyGoLib.h>

void setup() {
    instance.begin();
    Serial.printf("Battery: %u mV\n", instance.getBattVoltage());
    Serial.printf("Charging: %s\n", instance.isCharging() ? "Yes" : "No");
}

void loop() {}

Notes

NFC: ST25R3916 — the LilyGoLib includes a ready-to-use NFC driver
Microphone (T3902): PDM microphone; LilyGoLib initializes its GPIO17 clock and GPIO18 data interface
GNSS: MIA-M10Q multi-constellation GPS; allow 60–90 seconds for cold fix outdoors
MicroSD: Maximum 32 GB, formatted as FAT32
Power button: Hold 1 s to power on; hold 6 s to power off

FAQ

Q: Cannot upload? A: Connect USB-C, hold BOOT, press and release RST, then release BOOT. Upload the sketch and press RST to exit download mode.

Q: AMOLED display is blank after upload? A: Ensure Board is LilyGo T-Watch-Ultra, USB CDC On Boot is Enabled, and the partition scheme is 16M Flash (3MB APP/9.9MB FATFS).

T-Watch Ultra Quick Start ​

Dependencies ​

Arduino ​

PlatformIO ​

Arduino IDE ​

Board Settings ​

Steps ​

LVGL ​

Hello World ​

Peripheral Examples ​

Display (AMOLED — LilyGoLib) ​

Touch ​

LoRa (SX1262 — RadioLib) ​