T-Watch 2021 Quick Start

Dependencies

Library	Version	Source
TTGO_TWatch_Library	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/TTGO_TWatch_Library.git

3. Open platformio.ini and under [platformio] uncomment the T-Watch-2021 environment
4. Click ✓ to compile, connect USB-C, click → to upload

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Arduino IDE

Board Settings

Setting	Value
Board	ESP32 Dev Module
Upload Speed	921600
CPU Frequency	240 MHz (WiFi/BT)
Flash Size	16MB (128Mb)
Partition Scheme	16M Flash (3MB APP/9.9MB FATFS)
PSRAM	Enabled

Steps

1. Install Arduino IDE and add ESP32 board support: https://espressif.github.io/arduino-esp32/package_esp32_index.json
2. Clone the library and add it via Sketch → Include Library → Add .ZIP Library
3. Open an example, set the watch model in config.h (e.g., #define LILYGO_WATCH_2021)
4. Apply the board settings above and click Upload

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LVGL

T-Watch 2021 uses LVGL v7 via the TTGO_TWatch_Library. Call watch->lvgl_begin() to initialize the display and touch driver.

Hello World

#include "LilyGoWatch.h"

TTGOClass *watch;

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

    lv_obj_t *label = lv_label_create(lv_scr_act());
    lv_label_set_text(label, "T-Watch 2021");
    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 2021");
}

void loop() {}

Touch (FT6336)

#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);
}

PMU (AXP202 — 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() {}

IMU (BMA423 — TTGO_TWatch_Library)

#include "LilyGoWatch.h"

TTGOClass *watch;

void setup() {
    watch = TTGOClass::getWatch();
    watch->begin();
    watch->bma->accelConfig.odr = BMA4_OUTPUT_DATA_RATE_100HZ;
    watch->bma->accelConfig.range = BMA4_ACCEL_RANGE_4G;
    watch->bma->accelConfig.bandwidth = BMA4_ACCEL_NORMAL_AVG4;
    watch->bma->accelConfig.perf_mode = BMA4_CONTINUOUS_MODE;
    watch->bma->accelEnable();
}

void loop() {
    Accel acc;
    if (watch->bma->getAccel(acc)) {
        Serial.printf("X=%.2f Y=%.2f Z=%.2f\n",
            acc.x * 0.001f, acc.y * 0.001f, acc.z * 0.001f);
    }
    delay(100);
}

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FAQ

Q: Which config.h macro should I use for T-Watch 2021? A: Define LILYGO_WATCH_2021 in config.h before including the library.

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

Q: Touch or sensor not working after upload? A: Ensure the correct watch model macro is defined; using the wrong macro will map incorrect GPIO pins.