T-Watch Ultra Quick Start

Dependencies

Library	Version	Source
LilyGoLib	latest	GitHub
RadioLib	latest	GitHub
XPowersLib	latest	GitHub

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Arduino

PlatformIO (Recommended)

1. Install VS Code and the PlatformIO IDE extension
2. Clone the repository:

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

3. Open platformio.ini, uncomment the T-Watch-Ultra environment
4. Click ✓ to compile, connect USB-C, click → to upload

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Arduino IDE

Board Settings

Setting	Value
Board	ESP32S3 Dev Module
Upload Speed	921600
USB Mode	Hardware CDC and JTAG
USB CDC On Boot	Enabled
CPU Frequency	240 MHz (WiFi)
Flash Mode	QIO 80 MHz
Flash Size	16MB (128Mb)
Partition Scheme	16M Flash (3MB APP/9.9MB FATFS)
PSRAM	OPI PSRAM

Steps

1. Install Arduino IDE and add ESP32 board support: https://espressif.github.io/arduino-esp32/package_esp32_index.json
2. Clone the LilyGoLib repository and open an example
3. Apply the board settings above and click Upload

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LVGL

T-Watch Ultra uses LVGL v8 via LilyGoLib. The library handles AMOLED display init, touch, and flush automatically.

Hello World

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

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

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

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

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Peripheral Examples

Display (AMOLED — LilyGoLib)

#include <LilyGoLib.h>

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

void loop() {}

Touch

#include <LilyGoLib.h>

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

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

LoRa (SX1262 — RadioLib)

#include <RadioLib.h>

// Verify LoRa pins in LilyGoLib/src/LilyGoWatch.h for T-Watch Ultra
#define LORA_CS    36
#define LORA_IRQ   45
#define LORA_RST   42
#define LORA_BUSY  46

SX1262 radio = new Module(LORA_CS, LORA_IRQ, LORA_RST, LORA_BUSY);

void setup() {
    Serial.begin(115200);
    int state = radio.begin(915.0, 125.0, 9, 7, RADIOLIB_SX126X_SYNC_WORD_PRIVATE, 22);
    if (state != RADIOLIB_ERR_NONE) Serial.printf("LoRa init failed: %d\n", state);
}

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

GPS (MIA-M10Q — TinyGPSPlus)

#include <TinyGPSPlus.h>
#include <HardwareSerial.h>

#define GPS_RX  10
#define GPS_TX  11

TinyGPSPlus gps;
HardwareSerial GPSSerial(1);

void setup() {
    Serial.begin(115200);
    GPSSerial.begin(38400, SERIAL_8N1, GPS_RX, GPS_TX);
}

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

PMU (AXP2101 — LilyGoLib)

#include <LilyGoLib.h>

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

void loop() {}

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Notes

• NFC: ST25R3916 — the LilyGoLib includes a ready-to-use NFC driver
• Cellular (T3902): Requires a SIM card inserted; use the modem examples from LilyGoLib
• GNSS: MIA-M10Q multi-constellation GPS; allow 60–90 seconds for cold fix outdoors
• Power button: Hold 2 s to power on; hold 6 s to force off

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FAQ

Q: Cannot upload? A: Hold BOOT, press RST once, release BOOT, then retry uploading.

Q: AMOLED display is blank after upload? A: Ensure USB CDC On Boot is Enabled and partition scheme is 16M Flash (3MB APP).