Yes
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TTGO T-Watch
Smartwatch-style ESP32 board with display, battery, and sensors - great for wearable IoT and portable dashboards.
47 × 40 mm
ESP32
MCU
240MHz
clock
16MB
flash
520KB
SRAM
18· Two 12-bit, 18 Channels ADC
GPIO
BLE 4.2+ WiFi
radio
Pinout
18 pins| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 1 | TXPWM | uart | uart | |
| 2 | 2 | MISOPWM | strapping | spi | |
| 3 | 3 | RXPWM | uart | uart | |
| 4 | 13 | SSPWM | strapping | spi | |
| 5 | 14 | SCKPWM | strapping | spi | |
| 6 | 15 | MOSIPWM | strapping | spi | |
| 7 | 21 | SDAPWM | safe | i2c | |
| 8 | 22 | SCLPWM | safe | i2c | |
| 9 | 23 | TP_SDAPWM | safe | - | |
| 10 | 25 | DAC1PWM | safe | dac | |
| 11 | 26 | DAC2PWM | safe | dac | |
| 12 | 32 | TP_SCLPWM | safe | - | |
| 13 | 33 | TX1PWM | safe | - | |
| 14 | 34 | RX1 | strapping | - | |
| 15 | 35 | APX20X_INT | strapping | - | |
| 16 | 37 | RTC_INT | strapping | - | |
| 17 | 38 | TP_INT | strapping | - | |
| 18 | 39 | BMA42X_INT1 | strapping | - |
Start with these
7 pins with no boot or system involvementSDAPWMSCLPWMTP_SDAPWMDAC1PWMDAC2PWMTP_SCLPWMTX1PWM
Freely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.
Fine - with a little care
sampled at boot or shared with debug/serial| Pin | Label | What to know | Role |
|---|---|---|---|
| MISO | GPIO2 | If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure. | Strapping |
| SS | MTCK (GPIO13) | Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed. | Other |
| SCK | MTMS (GPIO14) | Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot. | Other |
| MOSI | MTDO (GPIO15) | Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change. | Strapping |
| RX1 | GPIO34 | Cannot be used as output (no drive capability); only suitable for analog/digital input. | Other |
| APX20X_INT | GPIO35 | Cannot be used as output; only suitable for input. | Other |
| RTC_INT | GPIO37 (SENSOR_CAPP) | Cannot be used as output; only suitable for input. | Other |
| TP_INT | GPIO38 (SENSOR_CAPN) | Cannot be used as output; only suitable for input. | Other |
| BMA42X_INT1 | GPIO39 (SENSOR_VN) | Cannot be used as output; only suitable for input. | Other |
Only if you know the tricks
wired to flash or USB - expect a fight| Pin | Label | What to know | Role |
|---|---|---|---|
| TX | U0TXD (GPIO1) | Connected to on-board USB-UART for uploading and logs; drives serial output at boot, so using as GPIO can disrupt programming or console. | USB |
| RX | U0RXD (GPIO3) | Used for receiving data from USB-UART (programming); also pulled HIGH at boot for console communication, so using as GPIO can disrupt uploads. | USB |
These are recommendations, not hard rules - with the right pull-ups, timing and boot-state awareness most pins can be made to work. When in doubt, start green.
Pinout notes All 18 pins on the TTGO T-Watch are usable GPIO. Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO21 and SCL on GPIO22; the SPI bus ( MOSI ,…
All 18 pins on the TTGO T-Watch are usable GPIO.
Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO21 and SCL on GPIO22; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO1 and GPIO3 cover serial logging and flashing.
Beyond plain digital I/O you get 2 true DAC outputs.
9 of the exposed pins carry boot-time or system duties on the ESP32 (MISO, SS, SCK and 6 more) - check the guidance above before wiring anything to them. SDA, SCL, TP_SDA, DAC1 and 3 more are free of any such role - the safest first picks.
Getting started
flash your first firmware in ~2 minutes1
Connect over USB
Uses a CP2104 bridge - install the CP210x driver if no port appears. Not detected? Hold BOOT while plugging in.
2
Match & flash
Set the Tools options shown, then click Upload.
3
Verify it runs
The onboard LED on GPIO21 blinks - swap the pin if your board's LED differs.
Set these in Tools · leave everything else at default
Arduino IDE 2.x — Tools Copy
Board: "ESP32 Wrover Module"▸
Flash Size: "16MB (128Mb)"▸
Flash Mode: "DIO"▸
PSRAM: "QSPI PSRAM"▸
Partition Scheme: "16M Flash (3MB APP / 9.9MB FATFS)" (default)▸
Upload Speed: "921600"▸
▸ every other Tools option — leave at default
Board: ESP32 Wrover Module Flash Size: 16MB (128Mb) Flash Mode: DIO PSRAM: QSPI PSRAM Partition Scheme: 16M Flash (3MB APP / 9.9MB FATFS) Upload Speed: 921600
Find it: Tools ▸ Board ▸ ESP32 Arduino ▸ ESP32 Wrover Module
// blink the onboard LED
void setup() {
pinMode(21, OUTPUT);
}
void loop() {
digitalWrite(21, HIGH); delay(500);
digitalWrite(21, LOW); delay(500);
}board to selectesp32dev⧉ copy
[env:twatch]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600
board_build.arduino.memory_type = qio_qspi
build_flags = -DBOARD_HAS_PSRAMFind it: PlatformIO Home ▸ Boards, search
esp32dev — or type it after board =.board to selectesp32dev⧉ copy
esp32:
board: esp32dev
variant: twatch
framework:
type: esp-idf
psram:
mode: quad
speed: 80MHz
# blink - GPIO21
output:
- platform: gpio
pin: 21
id: led_out
light:
- platform: binary
name: "LED"
output: led_outFind it: search ESPHome's board list for
esp32dev (same ids as PlatformIO).esptool doesn't pick board settings — a prebuilt .bin already has them baked in. This is just the raw flash command.
esptool.py --chip esp32 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x0 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Build details: sketch space 6553600 B · data 4521984 B · DIO
Specifications
ESP32 · 47 × 40 mmCompute
MCU
ESP32
Clock
240 MHz
SRAM · Flash
520 KB · 16MB · 8MB (QSPI) PSRAM
Radio
Wi-Fi
802.11 b/g/n
Bluetooth
4.2 LE
Antenna
PCB
I/O
GPIO · ADC
18 · Two 12-bit, 18 Channels
UART · I²C · SPI
3 · 2 · 4
PWM
16 channels
Power
USB
Micro-USB
Serial
CP2104
Boot address
0x1000
Display
Screen
IPS LCD · 1.54" · 240x240
Driver
ST7789V
Touch
FT6336
Flashing
Upload · OTA
esptool_py · esp_ota
Flash · Boot mode
DIO · DIO
Sketch · Data
6.25 MB · 4.31 MB
47 × 40 mm
The TTGO T-Watch uses esptool_py for firmware uploads, esp_ota for over-the-air (OTA) updates. Flash mode is DIO with DIO boot mode. The maximum sketch size is 6.25 MB with 4.31 MB available for data.
About this board
Inside sits the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.
At $36.55 it's on the expensive side for an ESP32 board - most land around $20.
Only 18 GPIO are broken out, where most ESP32 boards manage about 24 - worth checking the pinout covers what you need.
Around the module: 8MB (QSPI) PSRAM, an IPS LCD 1.54" 240x240 display with touch, a microphone, a speaker, an amplifier (MAX98357A), a PCF8563 RTC, an IR transceiver, a motion sensor (BMA423), battery charging (AXP202) and Power buttons.
- Vibration motor for haptic feedback
- Built-in rechargeable Li-Po battery
- PDM microphone (SPM1423) added on V3 for voice control
- AXP202 PMU manages charging and power rails
Where to buy
prices are typical street pricesTTGO T-Watch
$36.55per unit, typical
Resources
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