DIY Projects

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

ttgo lilygo t-watch touch gpio expansion boards axp202

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The official documentation available here is out of date (at the time of writing).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.

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).

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 .

 

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.

Peripheral T-Watch 2019 TOUCH T-Watch 2019 NO TOUCH T-BLOCK
RTC clock PCF8563 PCF8563 PCF8563
3-axis accelerometer BMA423 BMA423 MPU6050
Power Manager AXP202 AXP202 AXP202

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.

Attention, expansion boards are not compatible with the T-Block!

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:

Basic Expansion Board Pinout

ESP32 Function Description
MicroSD card reader
GPIO13 CS TF_CS
GPIO15 DAWDLE TF_MOSI
GPIO02 MISO TF_MISO
GPIO14 SCLK TF_SCLK
Connector 4-pin , I2C bus
GPIO25 I2C SDA
GPIO26 I2C SCL
8 pin connector
GPIO33 User
GPIO34 User
GPIO21 I2C SDA
GPIO22 I2C SCL

SIM800 GPRS modem. Internet connectivity, sending and receiving SMS

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

A SIM card is required. Check the availability of supported frequencies in your country.

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

ESP32 Function Description
SIM800L modem
GPIO33 TX UART_SIM_TX
GPIO34 RX UART_SIM_RX
GPIO14 RST SIM_RST
GPIO15 PWKEY SIM_PWKEY
GPIO04 BOOST SIM_BOOST_CTRL
Connector 4-pin , I2C bus
GPIO25 * I2C SDA
GPIO26* I2C SCL
MicroSD card reader
GPIO13 CS TF_CS
GPIO15 DAWDLE TF_MOSI
GPIO02 MISO TF_MISO
GPIO14 SCLK TF_SCLK

(*) 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

ESP32 Function Description
GPS u-blox NEO M8N
GPIO33 TX UART_GPS_TX
GPIO34 RX UART_GPS_RX
Connector 4-pin , I2C bus
GPIO21* I2C SDA
GPIO22* I2C SCL
MicroSD card reader
GPIO13 CS TF_CS
GPIO15 DAWDLE TF_MOSI
GPIO02 MISO TF_MISO
GPIO14 SCLK TF_SCLK

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

ESP32 Function Description
AcSIP S76GX or S78GX GPS receiver
GPIO33 TX UART_GPS_TX
GPIO34 RX UART_GPS_RX
LoRa AcSIP S76GX (868MHz – Europe) or S78GX (433MHz – Asia) modem
GPIO25 LCK SX1276_LCK
GPIO26 BCK SX1276_BCK
GPIO33 FROM SX1276_DIN
Connector 4-pin , I2C bus
GPIO21* I2C SDA
GPIO22* I2C SCL
MicroSD card reader
GPIO13 CS TF_CS
GPIO15 DAWDLE TF_MOSI
GPIO02 MISO TF_MISO
GPIO14 SCLK TF_SCLK

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.

Expansion board Pins
Microphone MIC_DATA 34
MIC_CLOCK 26
GamePad GAMECONTROL_CONTS 5
GAMECONTROL_PINS {13,14,25,26,15}
GAMECONTROL_BUZZER 4
MAX98357A + INMP441 MAX98357A

TWATCH_DAC_IIS_BCK 26
TWATCH_DAC_IIS_WS 25
TWATCH_DAC_IIS_DOUT 33

INMP441

TWATCH_INMP441_IIS_BCK 15
TWATCH_INMP441_IIS_WS 13
TWATCH_INMP441_IIS_DIN 14

PN532 TWATCH_PN532_IRQ 34
TWATCH_PN532_RESET 33
T-Quick

2 motor outputs

TWATCH_TQUICK_EN 2
TWATCH_TQUICK_MA1 26
TWATCH_TQUICK_MA2 25
TWATCH_TQUICK_MB1 13
TWATCH_TQUICK_MB2 15
Carte Lora SX1276

Lora only. Communication via the SPI bus

 

TWATCH_LORA_SCK 14
TWATCH_LORA_MISO 2
TWATCH_LORA_MOSI 15
TWATCH_LORA_SS 13
TWATCH_LORA_DI0 26
TWATCH_LORA_RST 25

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