ESP32-S3-USB-OTG
by Espressif
A development board by Espressif focusing on USB-OTG functionality, suitable for applications like video streaming over Wi-Fi and connecting to wireless USB devices.

On this page
Pinout
37 pins| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 0 | BUTTON_OK | strapping | - | |
| 2 | 1 | A0HOST_VOLTSPWM | safe | adc | |
| 3 | 2 | A1BAT_VOLTSPWM | safe | adc | |
| 4 | 3 | A2T3PWM | strapping | adc · touch | |
| 5 | 4 | LCD_DCPWM | safe | - | |
| 6 | 5 | LCD_CSPWM | safe | - | |
| 7 | 6 | LCD_CLKPWM | safe | - | |
| 8 | 7 | LCD_MOSIPWM | safe | - | |
| 9 | 8 | LCD_RSTPWM | safe | - | |
| 10 | 9 | LCD_BLPWM | strapping | - | |
| 11 | 10 | BUTTON_UPPWM | strapping | - | |
| 12 | 11 | BUTTON_DOWNPWM | strapping | - | |
| 13 | 12 | DEV_VBUS_ENPWM | strapping | - | |
| 14 | 13 | BOOST_ENPWM | strapping | - | |
| 15 | 14 | BUTTON_MENUPWM | strapping | - | |
| 16 | 15 | LED_GREENPWM | safe | - | |
| 17 | 16 | LED_YELLOWPWM | safe | - | |
| 18 | 17 | LIMIT_ENPWM | safe | - | |
| 19 | 18 | USB_HOST_ENPWM | safe | - | |
| 20 | 19 | USB_DNPWM | uart | - | |
| 21 | 20 | USB_DPPWM | uart | - | |
| 22 | 21 | OVER_CURRENTPWM | safe | - | |
| 23 | 33 | SDMMC_D2PWM | strapping | - | |
| 24 | 34 | SSSDMMC_D3PWM | strapping | spi | |
| 25 | 35 | MOSISDMMC_CMDPWM | strapping | spi | |
| 26 | 36 | SCKSDMMC_CLKPWM | strapping | spi | |
| 27 | 37 | MISOSDMMC_D0PWM | strapping | spi | |
| 28 | 38 | SDMMC_D1PWM | strapping | - | |
| 29 | 39 | MTCKPWM | strapping | - | |
| 30 | 40 | MTDOPWM | strapping | - | |
| 31 | 41 | MTDIPWM | strapping | - | |
| 32 | 42 | MTMSPWM | strapping | - | |
| 33 | 43 | TXPWM | strapping | uart | |
| 34 | 44 | RXPWM | strapping | uart | |
| 35 | 45 | SDAPWM | strapping | i2c | |
| 36 | 46 | SCL | strapping | i2c | |
| 37 | - | LCD_MISO | safe | - |
Start with these
12 pins with no boot or system involvementFreely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.
Fine - with a little care
sampled at boot or shared with debug/serial| Pin | Label | What to know | Role |
|---|---|---|---|
| BUTTON_OK | GPIO0 | Must be pulled high (default) or low (to enter UART download mode) at reset. Using it for other functions can interfere with boot mode configuration. | Strapping |
| A2 | GPIO3 | Sampled at reset to select JTAG interface (USB Serial/JTAG controller vs. external pins). Improper use can disable external JTAG or alter debug interface. | Strapping |
| MTCK | MTCK (GPIO39) | Default JTAG debugging TCK pin. If JTAG is needed, this pin must be free; it may also be used internally for PSRAM chip select on certain modules, so avoid repurposing it. | Other |
| MTDO | MTDO (GPIO40) | Default JTAG TDO output for debugging. Using it as GPIO will interfere with JTAG debugging functionality. | Other |
| MTDI | MTDI (GPIO41) | Default JTAG TDI input for debugging. Should be reserved for JTAG or left unused if JTAG is to remain available. | Other |
| MTMS | MTMS (GPIO42) | Default JTAG TMS signal for debugging. Using this pin for other purposes will disable the JTAG interface (unless JTAG is rerouted to USB). | Other |
| TX | U0TXD (GPIO43) | Used for bootloader output and UART console logs. If repurposed, you will lose the default serial output (and programming via UART0). | Other |
| RX | U0RXD (GPIO44) | Used for bootloader input (download mode via serial). If repurposed, you cannot use the default UART0 download mode for programming the chip. | Other |
| SDA | GPIO45 | Determines flash/PSRAM power voltage (3.3 V vs 1.8 V) at boot. Must match hardware configuration; using as GPIO can upset flash supply setting. | Strapping |
| SCL | GPIO46 | Must be at a defined level during reset (with GPIO0) to select normal or download boot and UART/USB print mode. This pin is input-only (no output drive), so it should be left for its intended strapping function. | Strapping |
Only if you know the tricks
wired to flash or USB - expect a fight| Pin | Label | What to know | Role |
|---|---|---|---|
| LCD_BL | FSPIHD | Connected to external flash (data/hold signal) on most modules. Not recommended for use as GPIO, since it must remain dedicated to flash communication. | Flash |
| BUTTON_UP | FSPICS0 | Used to select the external flash chip. It is required for flash access and cannot be repurposed without losing flash connectivity | Flash |
| BUTTON_DOWN | FSPID | Used as a data line for flash (and in-package PSRAM). It should not be used as GPIO when the flash/PSRAM is in use. | Flash |
| DEV_VBUS_EN | FSPICLK | Drives the flash (and PSRAM) clock. This critical signal must be reserved for memory and not used as general GPIO. | Flash |
| BOOST_EN | FSPIQ | Used as a data line for flash/PSRAM transfers. Not available for other uses when flash/PSRAM is connected. | Flash |
| BUTTON_MENU | FSPIWP | Connected to external flash (data/write-protect signal). Not recommended as GPIO because it’s reserved for flash operations. | Flash |
| USB_DN | USB_D- | By default connected to the on-chip USB Serial/JTAG controller. Using it as general GPIO without reconfiguring IO MUX will interfere with USB functionality. | USB |
| USB_DP | USB_D+ | By default connected to the on-chip USB Serial/JTAG controller. Using it as general GPIO without reconfiguring IO MUX will interfere with USB functionality. | USB |
| SDMMC_D2 | FSPIHD | On chips/modules with integrated flash, this IO is wired to the flash hold pin internally. It cannot be reassigned to GPIO without breaking flash access. | Flash |
| SS | FSPICS0 | Wired to the chip select of the internal flash in flash-equipped variants. It must remain low during flash operation, so it’s not available for other use. | Flash |
| MOSI | FSPID / PSRAM_D0 | In modules with octal PSRAM, this pin is connected to the PSRAM data line. It is reserved for memory interface and not free for general GPIO when flash/PSRAM is present. | Flash |
| SCK | FSPICLK / PSRAM_CLK | In modules with octal PSRAM, this pin drives the PSRAM clock. It must be dedicated to the memory interface, not used as a regular GPIO when that interface is in use. | Flash |
| MISO | FSPIQ / PSRAM_DQS | In modules with octal PSRAM, this pin is connected to the PSRAM’s DQS signal. It cannot be repurposed without disrupting the PSRAM/flash communication. | Flash |
| SDMMC_D1 | FSPIWP | On flash-equipped chips, this pin is tied to the flash’s WP# (or D3) line. It should be avoided for other use, as it’s needed for flash operations. | Flash |
Pinout notes The ESP32-S3-USB-OTG breaks out 37 pins in total: 36 GPIO for your project. Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO45 and SCL on…
The ESP32-S3-USB-OTG breaks out 37 pins in total: 36 GPIO for your project.
Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO45 and SCL on GPIO46; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO43 and GPIO44 cover serial logging and flashing.
Beyond plain digital I/O you get 3 ADC-capable pins for sensors and battery monitoring and 1 capacitive-touch inputs.
10 of the exposed pins carry boot-time or system duties on the ESP32-S3 (BUTTON_OK, A2, MTCK and 7 more) - check the guidance above before wiring anything to them. A0, A1, LCD_DC, LCD_CS and 8 more are free of any such role - the safest first picks.
Getting started
flash your first firmware in ~2 minutesBoard: ESP32S3 Dev Module USB CDC On Boot: Enabled Flash Size: 8MB (64Mb) Flash Mode: DIO Partition Scheme: 8M with spiffs (3MB APP / 1.5MB SPIFFS) Upload Speed: 921600
// blink the onboard LED
void setup() {
pinMode(1, OUTPUT);
}
void loop() {
digitalWrite(1, HIGH); delay(500);
digitalWrite(1, LOW); delay(500);
}[env:esp32s3usbotg]
platform = espressif32
board = esp32-s3-devkitc-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32-s3-devkitc-1 — or type it after board =.esp32:
board: esp32-s3-devkitc-1
variant: esp32s3usbotg
framework:
type: esp-idf
# blink - GPIO1
output:
- platform: gpio
pin: 1
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesp32-s3-devkitc-1 (same ids as PlatformIO).esptool.py --chip esp32s3 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x0 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Good to know
board-specific quirks worth 60 secondsSpecifications
ESP32-S3About this board
Inside sits the ESP32-S3 - a dual-core Xtensa with vector extensions suited to AI workloads.
At $35.00 it's on the expensive side for an ESP32-S3 board - most land around $30.
With 36 GPIO broken out, you get more pins to play with than most ESP32-S3 boards offer.
Around the module: an LCD 1.3" 240x240 display, a microSD slot, status LEDs (Green (GPIO15), Yellow (GPIO16), Charge) and Menu/Up/Down/Boot/Reset buttons.
It flashes over native USB - no serial-converter driver needed, which isn't a given among ESP32-S3 boards.
- USB-A female HOST port + USB-A male DEV port for USB-OTG host/device demos
- ESP32-S3-MINI-1-N8 (8MB flash, no PSRAM)
Where to buy
prices are typical street prices
Resources
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