LilyGO T-Dongle S3

The LilyGO T-Dongle-S3 board has a USB stick layout including a TFT color display, a APA102 LED, a input button and SD card slot.

This panel including advanced graphic features is supported by the HomeDing Display Example.

The following features are available on this board.

This board is equipped with:

ESP32-S3 processor
16 MByte Flash in QIO mode
80 * 160 px based on ST7735: 16-bit color, SPI
SD card slot
A momentary Input button
Color LED

ST7735 based display

The built-in display based on the ST7735 chip has a 80 * 160 resolution and is using the following pins:

function	ESP32 pin
CS	GPIO4
MOSI	GPIO3
CLK	GPIO5
DC	GPIO2
Reset	GPIO1
LED	GPIO38

As this display is using the available resolution of the ST7735 (132 x 162) only partally a column offset of 26 and a row offset of 1 must be configured.

This display is supported by the Arduino_GFX library mentioned as “096-ips-lcd-80x160”.

The complete configuration of the DisplayST7735 Element can be found below.

Faster SD Card

The SD Card inside the USB connector is connected directly to the ESP32-S3 processor using the MMC interface. As the ESP32-S3 processor offers flexibility in using custom defined pins a pin configuration (see below) must be given:

function	ESP32 pin
CLK	GPIO12
CMD	GPIO16
D0	GPIO14
D1	GPIO17
D2	GPIO21
D3	GPIO18

Input Button

The input button on the back of the stick pulls the esp32-pin 0 down when pressed.

function	ESP32 pin
Button	GPIO0

Don’t configure this button in the device configuration to start the config mode as it is set to active LOW

Color LED

The color LED on the backside is a APA102 LED supported by the APA102 Element.

Data and Clock lines are connected on these pins:

function	ESP32 pin
Data	40
Clock	39

Arduino Board Configuration

To compile for this board in Arduino the following settings for the board can be used:

ESP32S3 Dev Module
JTAG Adapter disabled
PSRam disabled
Flash Mode QIO 80 MHz
Flash Size: 4MB
USB Mode Hardware CDC and JTAG
USB CDC On Boot: Enabled

For the Arduino-CLI the following boardname and build properties can be used:

fqbn = "esp32:esp32:esp32s3"
properties = "JTAGAdapter=default,PSRAM=disabled,FlashMode=qio,FlashSize=16M,
  LoopCore=1,EventsCore=1,USBMode=hwcdc,CDCOnBoot=cdc,MSCOnBoot=default,DFUOnBoot=default,
  UploadMode=default,PartitionScheme=default,CPUFreq=240,UploadSpeed=921600,DebugLevel=none,EraseFlash=none"

Board configuration

The following env.json configuration can be used for this board and contains settings for

The device in general
The ST7735 based display
A value and pwm output to control the display brightness
The digital input signal definition for the button on the back.

{
  "device": {
    "0": {
      "name": "dongle-s3",
      "description": "ESP32-S3 based USB stick.",
      "title": "T-Dongle-S3",
      "loglevel": 2,
      "led": "38"
    }
  },

  "DisplayST7735": {
    "0": {
      "description": "Display",
      "width": "80",
      "height": "160",
      "rotation": 270,
      "colOffset": 26,
      "rowOffset": 1,
      "ips": 1,

      "busmode": "spi",
      "spiClk": 5,
      "spiMosi": 3,
      "spiDC": 2,
      "spiCS": 4,
      "resetpin": 1,

      "background": "black"
    }
  },

  "digitalin": {
    "pin": {
      "description": "Momentary button",
      "pin": "0",
      "inverse": "1",
      "pullup": 1
    }
  },

  "pwmout": {
    "displayled": {
      "title": "Backlight",
      "description": "Display Backlight",
      "pin": "38",
      "range": "255",
      "inverse": "1"
    }
  },

  "apa102": {
    "led": {
      "description": "RGB color LED",
      "datapin": 40,
      "clockpin": 39,
      "count": 1,
      "loglevel": 2,
      "duration": "4s"
    }
  },

  "sdmmc": {
    "0": {
      "mmcD0": "14",
      "mmcD1": "17",
      "mmcD2": "21",
      "mmcD3": "18",
      "mmcCLK": "12",
      "mmcCMD": "16"
    }
  }
}

Diag and chipinfo output

**Info**
DeviceName: dongle-s3
Build Date & Time: Jan 26 2024T08:09:56
State: []
Mac-address: F4:12:FA:41:xx:xx

no i2c bus.

Chip Infos:
  model: esp32s3(9)
  features: 00000012
    2.4GHz WiFi
    Bluetooth LE
  cores: 2
  revision: 0

Flash:  Size: 16384 kByte
  Mode: QIO(0)
  Speed: 80000000

PSRAM:  Size: 0 kByte