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RIOT Documentation

LILYGO TTGO T8 ESP32-S2 Board

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Support for LILYGO TTGO T8 ESP32-S2 Board @author Gunar Schorcht gunar@schorcht.net

\section esp32s2_lilygo_ttgo_t8 LILYGO TTGO T8 ESP32-S2

Table of Contents

  1. Overview
  2. Hardware
    1. MCU
    2. Board Configuration
    3. Board Pinout
  3. Flashing the Device

Overview

The Espressif LILYGO TTGO T8 ESP32-S2 (also known as LilyGo T-Display S2) is a ESP32-S2 board with an OLED Display and a TF Card slot.

LILYGO TTGO T8 ESP32-S2

The board has following main features:

FeatureSupport
ESP32-S2 SoCyes
4 MB Flashyes
8 MB QSPI RAMyes
SD Card slotyes
32.768KHz Crystalyes
OLED display ST77789yes

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Hardware

This section describes

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MCU

Most features of the board are provided by the ESP32-S2 SoC. For detailed information about the ESP32-S2 SoC variant (family) and ESP32x SoCs, see section esp32_mcu_esp32 “ESP32 SoC Series”.

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Board Configuration

The LILYGO TTGO T8 ESP32-S2 board uses the SPI_DEV(0) (FSPI) for the OLED Display. The GPIOs of SPI_DEV(0) are therefore not broken out. SPI_DEV(1) is used for the SD Card slot. These GPIOs are broken out and can also be used by other devices.

The LILYGO TTGO T8 ESP32-S2 has a USB-to-UART bridge on board. The USB D-/D+ signals of the USB-C connector are connected via DIP switches either to this USB-to-UART bridge (default) or to GPIO19/GPIO20 of the ESP32-S2. To use the USB OTG interface of the ESP32-S2, the USB D-/D+ signals must be connected to GPIO19 and GPIO20, see section esp32s2_lilygo_ttgo_t8_pinout “Pinout”. To use the USB OTG interface also for the console in this case, either the stdio_cdc_acm or the stdio_tinyusb_cdc_acm module must be enabled. This is automatically the case if the USBUS or tinyUSB stack is used.

The LILYGO TTGO T8 ESP32-S2 has a 32.768 kHz crystal on the board, which is connected to GPIO15 and GPIO16 via DIP switches (default). The crystal can be switched off via the DIP switches so that GPIO15 and GPIO16 become available at the headers, see section esp32s2_lilygo_ttgo_t8_pinout “Pinout”.

The following table shows the default board configuration, which is sorted according to the defined functionality of GPIOs. This configuration can be overridden by esp32_application_specific_configurations “application-specific configurations”.

Function | GPIOs | Remarks | Configuration :---------------|:-------|:--------|:---------------------------------- BUTTON0 | GPIO0 | | | ADC_LINE(n) | GPIO1 ... GPIO9 | | esp32_adc_channels "ADC Channels" DAC_LINE(n) | GPIO17, GPIO18 | | esp32_dac_channels "DAC Channels" GPIO38 | GPIO38 | OLED RESET (not broken out) | | I2C_DEV(0) SCL | GPIO7 | | esp32_i2c_interfaces "I2C Interfaces" I2C_DEV(0) SDA | GPIO8 | | esp32_i2c_interfaces "I2C Interfaces" PWM_DEV(0) | GPIO39, GPIO40, GPIO41, GPIO42 | - | esp32_pwm_channels "PWM Channels" PWM_DEV(1) | GPIO15, GPIO16 | if module `esp_rtc_timer_32k` is not used | esp32_pwm_channels "PWM Channels" SPI_DEV(0) CLK | GPIO36 | OLED CLK (not broken out) | | SPI_DEV(0) MISO | GPIO37 | OLED MISO (not broken out) | | SPI_DEV(0) MOSI | GPIO35 | OLED MOSI (not broken out) | | SPI_DEV(0) CS0 | GPIO34 | OLED CS0 (not broken out) | | SPI_DEV(1) CLK | GPIO12 | SD Card CLK | esp32_spi_interfaces "SPI Interfaces" SPI_DEV(1) MISO | GPIO37 | SD Card MISO | esp32_spi_interfaces "SPI Interfaces" SPI_DEV(1) MOSI | GPIO35 | SD Card MOSI | esp32_spi_interfaces "SPI Interfaces" SPI_DEV(1) CS0 | GPIO34 | SD Card CS | esp32_spi_interfaces "SPI Interfaces" UART_DEV(0) TxD | GPIO43 | Console | esp32_uart_interfaces "UART interfaces" UART_DEV(0) RxD | GPIO44 | Console | esp32_uart_interfaces "UART interfaces" USB D- | GPIO19 | if USB-to-UART bridge is not used | | USB D+ | GPIO20 | if USB-to-UART bridge is not used | |
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For detailed information about the peripheral configurations of ESP32-S2 boards, see section esp32_peripherals “Common Peripherals”.

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Board Pinout

The following figure shows the pinout as configured by the board definition.

LILYGO TTGO T8 ESP32-S2 Pinout

The corresponding board schematics can be found here

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Flashing the Device

Flashing RIOT is quite easy. The board has an USB-C connector which is either connected to the USB-to-UART bridge (default) with a built-in reset/boot/flash logic or to the USB signals of the ESP32-S2 SoC. The flash method depends on the configuration of the DIP switches, see section esp32s2_lilygo_ttgo_t8_pinout “Pinout”.

USB-C connector is connected to the USB-to-UART bridge (default)

Just connect the board to your host computer and type using the programming port:

BOARD=esp32s2-liligo-ttgo-t8 make flash ...

For detailed information about ESP32-S2 as well as configuring and compiling RIOT for ESP32-S2 boards, see esp32_riot.

USB-C connector is connected to the USB signals of the ESP32-S2 SoC

In this configuration the integrated USB-to-JTAG bridge can be used to flash the board. The USB-to-JTAG bridge is automatically activated in the download mode of the bootloader, provided that the eFuses JTAG_SEL_ENABLE and DIS_USB_JTAG are not burned (see also section esp32_jtag_interface_esp32s2 “JTAG Interface” strapping pin GPIO3).

For this purpose, connect the board to your host computer and enter the following command using the programming port:

USEMODULE=esp32s2-lilygo-ttgo-t8-usb BOARD=esp32s2-liligo-ttgo-t8 make flash ...

If RIOT is already on the device, it should automatically reset the device and enter the bootloader download mode. If

  • RIOT is not already on the device or
  • automatic reset does not work or
  • the device is stuck in some other mode,

the download mode has to be forced before by pressing the Reset (RST) button while holding the BOOT (BOT) button.

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