T-Watch and T-Block. ESP32 Core PCB and expansion boards pinout

In this article, you will find the ESP32 pinout of the different versions of T-Watch as well as those of the expansion board. All the drivers and libraries necessary for the integration of the components embedded on the expansion board are already implemented in the TWatch library available on GitHub . Using the official library, there is no need to manually assign pins in the Arduino code. 

The official documentation available here is out of date (at the time of writing). If you encounter any difficulties or errors, please let me know via the contact form using the button above.

Pinout of TTGO T-Watch and T-Block ESP32 Core PCB

The Core PCB is pre-installed in the box. It is the motherboard of the T-Watch built on the basis of an ESP32. The board is equipped with an AXP202 power manager also used to manage the power supply of accessories (GPRS modem, LoRa, GPS receiver, etc.) without going through that of the ESP32 (too limited), 16MB of memory flash and 8MB of SPRAM memory.

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The T-Block shares the same architecture as the T-Watch. It is the oldest box in the series equipped with a screen (non-touch e-paper).

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The T-Bot is a version that incorporates a daughter board on which an HC-SR04 ultrasonic proximity sensor is placed. The T-Block is then installed on a base equipped with a motor to transform the T-Bot into a mini robot! Up to 3 analog sensors can be installed on the expansion board in addition to the HC-SR04 .

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Peripheral	T-Watch 2019 TOUCH	T-Watch-N	T-Block / T-Bot
Core	ESP32-DOWDQ6	ESP32-DOWDQ6	ESP32-DOWDQ6
Flash	16MB	16MB	16MB
SPRAM	8MB	8MB	8MB
Screen	TFT ST7789	TFT ST7789	e-paper
Touch driver	FT6236	N/A	N/A
TFT Size	240×240/1.54	240×240/1.54	N/A
TFT RST	N/A	N/A	N/A
TFT MISO	N/A	N/A	N/A
TFT MOSI	19	19	N/A
TFT SCLK	18	18	N/A
TFT DC	27	27	N/A
TFT CS	5	5	N/A
TFT BackLight	12	12	N/A
SDA (1)	21	21	21
SCL (1)	22	22	22
FT6236 SDA	23	N/A	N/A
FT6236 SCL	32	N/A	N/A
BMA423 Interrupt	39	N/A	N/A
FT6236 Interrupt	38	N/A	N/A
PCF8563 Interrupt	37	37	37
Button 1	36	36	36
AXP202 Interrupt	35	35	35
Revision	211-191209

(1) The following devices use the I2C bus (default) of the ESP32.

Expansion boards available for T-Watch Touch and T-Watch-N

Here is the list of expansion board currently available. The list is continuously enriched.

• Pin Expansion Board (Basic) , 2 x 8-pin expansion connectors providing access to pins 33, 34, 21 (SDA), 22 (SCL) of ESP32 and IO0, IO1, IO2 and IO3 of AXP202 (power manager). This is the board delivered as standard
• GPS M8N
• Motor & Speaker (Pack H329), vibrator + speaker
• MPR121, external touch interface
• SIM800L, modem GPRS
• MP3 , MP3 player
• NFC , contactless reader (note, this is not an RFID reader)
• MAX98357 (Pack H328), oximeter
• S76G Lora + GPS (Pack H327),
• S78G Lora (433 to 470 MHz) + GPS (Pack H397). LoRa modem
• T-Car, can drive up to 3 servo motors via the 1-Wire bus
• T-Quick , can control up to 2 motors in I2C
• Game , joystick and 4 buttons to transform the T-Watch into a Gameboy!

Mounting an expansion board in the T-Watch Touch or T-Watch-N.

See more expansion boards for the T-Watch

Basic Expansion Board expansion board

Expansion board supplied by default is necessary which adds the following functions:

• MicroSD card reader (pin identification below)
• 2 8-pin 2.54mm pitch connectors (for standard jumper)
  • ESP32 pins: 33, 34, 21 (SDA), 22 (SCL)
  • AXP202 pins (power supply manager): IO0, IO1, IO2 and IO3, EXTEN
  • 3x GND
  • 2x VCCX 3,5V ~5V
  • 1x VDD 3V3
• 1x I2C connector to Molex 53015-0410 standard.
  • GND, 26, 25, VCC
  • A 4-pin cable fitted with a connector a cable fitted with a Molex 51065-0400 connector is supplied and can be purchased separately
• x1 VBUS solder connector
• x1 connector for LiPo battery to JST standard 2 pins 1.54mm pitch

Basic Expansion Board Pinout

SIM800 GPRS modem. Internet connectivity, sending and receiving SMS

Expansion board to send / receive SMS and connect the watch to the internet.

The SIM800 modem is a quad-band GSM / GPRS module that operates on GSM 850 MHz, EGSM 900 MHz, DCS 1800 MHz and PCS 1900 MHz frequencies. The SIM800L has multiple GPRS slots and supports the GPRS CS-1, CS-2, CS-3 and CS-4 coding schemes.

SIM800L expansion board pinout

(*) To be checked, may vary between versions

Activation of the SIM800L modem

Use these keys in the config.h file to activate the SIM800L modem support

LILYGO_WATCH_HAS_SIM800L

Useful links

Technical documentation

Sample code

U-blox NEO M8N GPS expansion board

The u-blox GPS of the NEO-M8 series uses simultaneous reception of up to three GNSS systems (GPS / Galileo with BeiDou or GLONASS). It will allow you to retrieve the positioning (longitude, latitude, altitude) as well as the time for your projects.

u-blox NEO M8N GPS module pinout

Activation of the u-blox NEO M8N GPS receiver

Use these keys in the config.h file to activate support for the M8N GPS receiver

LILYGO_WATCH_HAS_GPS

Useful links

U-blox NEO M8 series technical documentation

Sample code

LoRa expansion board (433 MHz or 868 MHz) + GPS (AcSIP S76GXB)

This expansion board can send and receive LoRa messages and perform GPS positioning. It has an S76G or S78G SiP from the manufacturer AcSIP.

Each SiP has a LoRa SEMTECH SX1276 (for the 863 MHz or 928 MHz band) or SX1278 (433MHz or 470MHz) modem on board.

The S76G and S78G also include a SONY CXD5603GF GPS chip which can receive the GPS / GPS + and GLONASS signals for positioning.

868MHZ version (S78G)

S76G or S78G expansion board pinout

The modem is powered by the LDO3 pin

Activating the LoRa modem

Use these keys in the config.h file to enable S7xG modem support

LILYGO_WATCH_HAS_S76_S78G

Useful links

AcSIP S76GXB and S78G technical documentation

C++ library 

Sample code

Other boards pinout

Here is the pinout of the other expansion boards.

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