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Adafruit Feather ESP32-S3 2MB PSRAM
A Feather-format board with 4MB Flash and 2MB PSRAM, featuring STEMMA QT connector and USB-C, suitable for low-power applications.
52.3 × 22.7 mm
ESP32-S3
MCU
240MHz
clock
4MB
flash
512KB
SRAM
25· 15 ADC
GPIO
BLE 5.0+ WiFi
radio
Pinout
25 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 1 | NEOPIXEL_NUMPWM | safe | - | |
| 2 | 3 | SDAA6T3PWM | strapping | adc · touch · i2c | |
| 3 | 4 | SCLA7T4PWM | safe | adc · touch · i2c | |
| 4 | 5 | A8T5PWM | safe | adc · touch | |
| 5 | 6 | A9T6PWM | safe | adc · touch | |
| 6 | 7 | I2C_POWERPIN_I2C_POWERPWM | safe | - | |
| 7 | 8 | A5T8PWM | safe | adc · touch | |
| 8 | 9 | A10T9PWM | strapping | adc · touch | |
| 9 | 10 | A11T10PWM | strapping | adc · touch | |
| 10 | 11 | A12T11PWM | strapping | adc · touch | |
| 11 | 12 | A13T12PWM | strapping | adc · touch | |
| 12 | 13 | LED_BUILTINA14T13PWM | strapping | adc · touch | |
| 13 | 14 | A4T14PWM | strapping | adc · touch | |
| 14 | 15 | A3PWM | safe | adc | |
| 15 | 16 | A2PWM | safe | adc | |
| 16 | 17 | A1PWM | safe | adc | |
| 17 | 18 | A0PWM | safe | adc | |
| 18 | 21 | NEOPIXEL_POWERPWM | safe | - | |
| 19 | 33 | PIN_NEOPIXELPWM | strapping | - | |
| 20 | 35 | MOSIPWM | strapping | spi | |
| 21 | 36 | SCKPWM | strapping | spi | |
| 22 | 37 | MISOPWM | strapping | spi | |
| 23 | 38 | RXPWM | strapping | uart | |
| 24 | 39 | TXPWM | strapping | uart | |
| 25 | 42 | SSPWM | strapping | spi |
Start with these
11 pins with no boot or system involvementNEOPIXEL_NUMPWMSCLA7A8T5A9T6I2C_POWERPIN_I2C_POWERA5T8A3PWMA2PWMA1PWMA0PWMNEOPIXEL_POWERPWM
Freely 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 |
|---|---|---|---|
| SDA | 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 |
| TX | 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 |
| SS | 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 |
Only if you know the tricks
wired to flash or USB - expect a fight| Pin | Label | What to know | Role |
|---|---|---|---|
| A10 | 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 |
| A11 | FSPICS0 | Used to select the external flash chip. It is required for flash access and cannot be repurposed without losing flash connectivity | Flash |
| A12 | 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 |
| A13 | FSPICLK | Drives the flash (and PSRAM) clock. This critical signal must be reserved for memory and not used as general GPIO. | Flash |
| LED_BUILTIN | FSPIQ | Used as a data line for flash/PSRAM transfers. Not available for other uses when flash/PSRAM is connected. | Flash |
| A4 | FSPIWP | Connected to external flash (data/write-protect signal). Not recommended as GPIO because it’s reserved for flash operations. | Flash |
| PIN_NEOPIXEL | 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 |
| 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 |
| RX | 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 |
These are recommendations, not hard rules - with the right pull-ups, timing and boot-state awareness most pins can be made to work. When in doubt, start green.
Pinout notes The Adafruit Feather ESP32-S3 2MB PSRAM pinout brings out 25 GPIO pins at a 2.54 mm pitch - every one of them usable in your project. For peripherals, I²C is…
The Adafruit Feather ESP32-S3 2MB PSRAM pinout brings out 25 GPIO pins at a 2.54 mm pitch - every one of them usable in your project.
For peripherals, I²C is mapped to SDA on GPIO3 and SCL on GPIO4; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO39 and GPIO38 cover serial logging and flashing.
On the analog side there are 15 ADC-capable pins for sensors and battery monitoring and 11 capacitive-touch inputs.
If you want zero surprises, NEOPIXEL_NUM, SCL, A8, A9 and 7 more are free of any such role - the safest first picks. 3 of the exposed pins carry boot-time or system duties on the ESP32-S3 (SDA, TX and SS).
Getting started
flash your first firmware in ~2 minutes1
Connect over USB
Native USB - shows up as a port right away, no driver needed. Not detected? Hold BOOT while plugging in.
2
Match & flash
Set the Tools options shown, then click Upload.
3
Verify it runs
The onboard LED on GPIO1 blinks - swap the pin if your board's LED differs.
Set these in Tools · leave everything else at default
Arduino IDE 2.x — Tools Copy
Board: "ESP32S3 Dev Module"▸
USB CDC On Boot: "Enabled"▸
Flash Size: "4MB (32Mb)"▸
Flash Mode: "DIO"▸
PSRAM: "QSPI PSRAM"▸
Partition Scheme: "Default 4MB with spiffs (1.2MB APP / 1.5MB SPIFFS)" (default)▸
Upload Speed: "921600"▸
▸ every other Tools option — leave at default
Board: ESP32S3 Dev Module USB CDC On Boot: Enabled Flash Size: 4MB (32Mb) Flash Mode: DIO PSRAM: QSPI PSRAM Partition Scheme: Default 4MB with spiffs (1.2MB APP / 1.5MB SPIFFS) Upload Speed: 921600
Find it: Tools ▸ Board ▸ ESP32 Arduino ▸ ESP32S3 Dev Module
// blink the onboard LED
void setup() {
pinMode(1, OUTPUT);
}
void loop() {
digitalWrite(1, HIGH); delay(500);
digitalWrite(1, LOW); delay(500);
}board to selectesp32-s3-devkitc-1⧉ copy
[env:adafruit_feather_esp32s3]
platform = espressif32
board = esp32-s3-devkitc-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600
board_build.arduino.memory_type = qio_qspi
build_flags = -DBOARD_HAS_PSRAMFind it: PlatformIO Home ▸ Boards, search
esp32-s3-devkitc-1 — or type it after board =.board to selectesp32-s3-devkitc-1⧉ copy
esp32:
board: esp32-s3-devkitc-1
variant: adafruit_feather_esp32s3
framework:
type: esp-idf
psram:
mode: quad
speed: 80MHz
# blink - GPIO1
output:
- platform: gpio
pin: 1
id: led_out
light:
- platform: binary
name: "LED"
output: led_outFind it: search ESPHome's board list for
esp32-s3-devkitc-1 (same ids as PlatformIO).esptool doesn't pick board settings — a prebuilt .bin already has them baked in. This is just the raw flash command.
esptool.py --chip esp32s3 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x0 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Build details: sketch space 1310720 B · data 327680 B · DIO
Specifications
ESP32-S3 · 52.3 × 22.7 mmCompute
MCU
ESP32-S3
Clock
240 MHz
SRAM · Flash
512 KB · 4MB · 2MB (QSPI) PSRAM
Radio
Wi-Fi
802.11 b/g/n
Bluetooth
5.0 LE
Antenna
PCB
I/O
GPIO · ADC
25 · 15
UART · I²C · SPI
3 · 2 · 4
PWM
8 channels
Power
USB
USB-C
Serial
Native (CDC)
Boot address
0x0
Flashing
Upload · OTA
esptool_py · esp_ota
Flash · Boot mode
DIO · QIO
Sketch · Data
1.25 MB · 320 KB
52.3 × 22.7 mm · pin pitch 2.54 mm
The Adafruit Feather ESP32-S3 2MB PSRAM uses esptool_py for firmware uploads, esp_ota for over-the-air (OTA) updates. Flash mode is DIO with QIO boot mode. The maximum sketch size is 1.25 MB with 320 KB available for data.
About this board
At its core is the ESP32-S3 - a dual-core Xtensa with vector extensions suited to AI workloads.
Expect to pay about $17.50 - less than the ~$30 most ESP32-S3 boards go for.
Onboard you'll find 2MB (QSPI) PSRAM, a STEMMA QT connector, an addressable RGB LED (GPIO33), a battery fuel gauge (MAX17048), battery charging (MCP73831) via JST-PH 2.0, status LEDs (On, Charge, User (D13)) and Reset/DFU (BOOT0) buttons.
It flashes over native USB - no serial-converter driver needed, which isn't a given among ESP32-S3 boards.
- Early units shipped with an LC709203F fuel gauge instead of the MAX17048
Where to buy
prices are typical street pricesAdafruit Feather ESP32-S3 2MB PSRAM
$17.50per unit, typical
Resources
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