T-Watch S3 Quick Start

Dependencies

Library	Version	Source
TTGO_TWatch_Library	latest (branch: t-watch-s3)	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 (branch t-watch-s3):

   git clone -b t-watch-s3 https://github.com/Xinyuan-LilyGO/TTGO_TWatch_Library.git

3. Open platformio.ini and under [platformio] uncomment the target 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	UART0/Hardware CDC
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 repository (branch t-watch-s3) and open an example sketch
3. Select config.h in the example and ensure the correct watch model is defined
4. Select the board settings above and click Upload

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LVGL

T-Watch S3 uses LVGL v8 via the TTGO_TWatch_Library. The library handles display init, flush callback, and touch input automatically through watch->lvgl_begin().

lv_conf.h

#define LV_COLOR_DEPTH     16
#define LV_HOR_RES_MAX    240
#define LV_VER_RES_MAX    240
#define LV_TICK_CUSTOM      1
#define LV_TICK_CUSTOM_INCLUDE "Arduino.h"
#define LV_TICK_CUSTOM_SYS_TIME_EXPR (millis())
#define LV_MEM_SIZE  (64 * 1024)

Hello World

#include "LilyGoWatch.h"

TTGOClass *watch;

void setup() {
    watch = TTGOClass::getWatch();
    watch->begin();
    watch->openBL();        // Turn on backlight
    watch->lvgl_begin();    // Init LVGL + display + touch

    lv_obj_t *label = lv_label_create(lv_scr_act());
    lv_label_set_text(label, "T-Watch S3");
    lv_obj_align(label, LV_ALIGN_CENTER, 0, 0);
}

void loop() {
    lv_task_handler();
    delay(5);
}

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Peripheral Examples

Display (ST7789 — TTGO_TWatch_Library)

#include "LilyGoWatch.h"

TTGOClass *watch;

void setup() {
    watch = TTGOClass::getWatch();
    watch->begin();
    watch->openBL();
    watch->tft->fillScreen(TFT_BLACK);
    watch->tft->setTextColor(TFT_WHITE, TFT_BLACK);
    watch->tft->setTextSize(2);
    watch->tft->setCursor(40, 100);
    watch->tft->print("T-Watch S3");
}

void loop() {}

Touch

#include "LilyGoWatch.h"

TTGOClass *watch;

void setup() {
    watch = TTGOClass::getWatch();
    watch->begin();
}

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

LoRa (SX1262 — RadioLib)

#include <RadioLib.h>

// Verify pins in the TTGO_TWatch_Library config for your variant
#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 S3");
    delay(2000);
}

PMU (AXP2101 — XPowersLib)

#include "LilyGoWatch.h"

TTGOClass *watch;

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

void loop() {}

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FAQ

Q: Which LoRa variant do I have — SX1262 or SX1280? A: Check the label on the LoRa module. SX1262 operates at 433–915 MHz; SX1280 operates at 2.4 GHz. Set the correct variant in config.h before compiling.

Q: Cannot upload? A: Hold BOOT, press RST once, release BOOT, then upload. This forces download mode.

Q: Display stays blank after flashing? A: Ensure USB CDC On Boot is Enabled and the partition scheme matches (16M Flash).