The T-Watch 2020 hardware devices

The LilyGo t-watch 2020 is a smart watch, based on the ESP32, which you must program yourself. If you want a fully functional smart watch with analogue and digital time display, step counter ... then do not buy the t-watch 2020!

If however you want to find out how to create your own smart watch with BliueTooth and Internet connectivity using C or MicroPython programming then do buy the t-watch!

The t-watch 2020 features:

• a dual core ESP32 CPU with BlueTooth and WiFi interfaces
• 16 MBytes of psram
• a BMA423 three-axis accelerometer
• a MAX98357a I2S audio amplifier
• a AXP202 power management unit
• a PCF8563 real time clock
• a 240x240 TFT screen controlled by a ST7789V display controller
• a touch screen controlled by a FT6236U touch screen controller
• it supports IR control, a vibration motor

https://t-watch_document-en.readthedocs.io

Here is a photo of the watch. The program shown on the display is not supplied.

Software examining the T-Watch 2020 hardware

The programs described in this section are available on github: https://github.com/uraich/twatch2020_firmware/tree/main/hardware

I2C devices

There are 2 I2C buses on the t-watch. To find out which devices are connected to these buses we can use i2cScanBus[0 or 1].py.

The I2C buses use the following connections:

Drivers for the T-Watch hardware:

Some time ago a custom version of MicroPython integrating lvgl and all drivers needed to drive the t-watch devices was published on
https://github.com/OPHoperHPO/lilygo-ttgo-twatch-2020-micropython. I got the drivers below , except of the I2S driver, from this source.

• The st7789_lvgl display driver
• The ft6x36 touch panel driver
• The Real-time clock and calendar: PCF8563 driver
• The Power System Management: AXP202 driver
• The Triaxial Acceleration Sensor: BMA423 driver
• The Max9837 I2S Audio Power Amplifier: t-watch sound
• The buzzer and vibration motor t-watch buzzer
• The IR remote control: t-watch IR
• The ttgo module

-- Uli Raich - 2021-01-08

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