Adafruit Feather ESP32-S3 No PSRAM

by Adafruit

Similar to the previous model but without PSRAM, offering 8MB Flash and ideal for applications not requiring large memory buffers.

USB-C Native USB

Buy · $17.50 Pinout Datasheet ↗

52.3 × 22.7 mm

ESP32-S3

MCU

240MHz

clock

8MB

flash

512KB

SRAM

25· 15 ADC

GPIO

BLE 5.0+ WiFi

radio

Pinout

25 pins · 2.54 mm pitch

View:

Adafruit Feather ESP32-S3 No PSRAM pinout diagram

Pin	GPIO	Labels	Status	Capabilities
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	uart	uart
24	39	TXPWM	strapping	uart
25	42	SSPWM	strapping	spi

Start with these

12 pins with no boot or system involvement

NEOPIXEL_NUMPWMSCLA7A8T5A9T6I2C_POWERPIN_I2C_POWERA5T8A3PWMA2PWMA1PWMA0PWMNEOPIXEL_POWERPWMRXPWM

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
A10	FSPIHD	IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet lists it as a priority-2 pin ("can be freely used without restrictions"), so it is only taken if your board wires flash, an SD card or a display to FSPI.	Other
A11	FSPICS0	IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet lists it as a priority-2 pin ("can be freely used without restrictions"), so it is only taken if your board wires flash, an SD card or a display to FSPI.	Other
A12	FSPID	IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet lists it as a priority-2 pin ("can be freely used without restrictions"), so it is only taken if your board wires flash, an SD card or a display to FSPI.	Other
A13	FSPICLK	IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet lists it as a priority-2 pin ("can be freely used without restrictions"), so it is only taken if your board wires flash, an SD card or a display to FSPI.	Other
LED_BUILTIN	FSPIQ	IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet lists it as a priority-2 pin ("can be freely used without restrictions"), so it is only taken if your board wires flash, an SD card or a display to FSPI.	Other
A4	FSPIWP	IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet lists it as a priority-2 pin ("can be freely used without restrictions"), so it is only taken if your board wires flash, an SD card or a display to FSPI.	Other
TX	MTCK (GPIO39)	Default JTAG TCK - keep it free if you debug over JTAG. It is not a flash or PSRAM line on standard modules: those sit on GPIO26-37.	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
PIN_NEOPIXEL	SPIIO4 (GPIO33)	The datasheet keeps GPIO33-37 for "the higher 4 bits data line interface and DQS interface for the SPI0/1 interface in 8-line SPI mode", so octal-PSRAM modules (N16R8 and friends) consume it and do not break it out. On quad-PSRAM or PSRAM-less parts it is an ordinary GPIO - check which variant your module carries.	Flash
MOSI	SPIIO6 (GPIO35)	The datasheet keeps GPIO33-37 for "the higher 4 bits data line interface and DQS interface for the SPI0/1 interface in 8-line SPI mode", so octal-PSRAM modules (N16R8 and friends) consume it and do not break it out. On quad-PSRAM or PSRAM-less parts it is an ordinary GPIO - check which variant your module carries.	Flash
SCK	SPIIO7 (GPIO36)	The datasheet keeps GPIO33-37 for "the higher 4 bits data line interface and DQS interface for the SPI0/1 interface in 8-line SPI mode", so octal-PSRAM modules (N16R8 and friends) consume it and do not break it out. On quad-PSRAM or PSRAM-less parts it is an ordinary GPIO - check which variant your module carries.	Flash
MISO	SPIDQS (GPIO37)	The datasheet keeps GPIO33-37 for "the higher 4 bits data line interface and DQS interface for the SPI0/1 interface in 8-line SPI mode", so octal-PSRAM modules (N16R8 and friends) consume it and do not break it out. On quad-PSRAM or PSRAM-less parts it is an ordinary GPIO - check which variant your module carries.	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 All 25 pins on the Adafruit Feather ESP32-S3 No PSRAM are usable GPIO, spaced at the standard 2.54 mm pitch. Peripheral wiring is straightforward: I²C is…

All 25 pins on the Adafruit Feather ESP32-S3 No PSRAM are usable GPIO, spaced at the standard 2.54 mm pitch.

Peripheral wiring is straightforward: 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.

Beyond plain digital I/O you get 15 ADC-capable pins for sensors and battery monitoring and 11 capacitive-touch inputs.

9 of the exposed pins carry boot-time or system duties on the ESP32-S3 (SDA, A10, A11 and 6 more) - check the guidance above before wiring anything to them. NEOPIXEL_NUM, SCL, A8, A9 and 8 more are free of any such role - the safest first picks.

Getting started

flash your first firmware in ~2 minutes

Tool:

Connect over USB

Native USB - shows up as a port right away, no driver needed. Not detected? Hold BOOT while plugging in.

Match & flash

Set the Tools options shown, then click Upload.

Verify it runs

GPIO1 toggles - wire an LED and resistor to it, or change the pin to your board's own LED.

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: "8MB (64Mb)"▸

Flash Mode: "DIO"▸

Partition Scheme: "8M with spiffs (3MB 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: 8MB (64Mb)
Flash Mode: DIO
Partition Scheme: 8M with spiffs (3MB APP/1.5MB SPIFFS)
Upload Speed: 921600

Find it: Tools ▸ Board ▸ ESP32 Arduino ▸ ESP32S3 Dev Module

blink.ino Copy

// toggle GPIO1 - wire an LED and resistor to it
void setup() {
  pinMode(1, OUTPUT);
}
void loop() {
  digitalWrite(1, HIGH); delay(500);
  digitalWrite(1, LOW);  delay(500);
}

board to selectesp32-s3-devkitc-1⧉ copy

platformio.ini Copy

[env:adafruit_feather_esp32s3_nopsram]
platform = espressif32
board = esp32-s3-devkitc-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600

Find it: PlatformIO Home ▸ Boards, search esp32-s3-devkitc-1 - or type it after board =.

board to selectesp32-s3-devkitc-1⧉ copy

device.yaml Copy

esp32:
  board: esp32-s3-devkitc-1
  variant: esp32s3
  framework:
    type: esp-idf

# blink - GPIO1
output:
  - platform: gpio
    pin: 1
    id: led_out
light:
  - platform: binary
    name: "LED"
    output: led_out

Find 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.

terminal Copy

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 mm · vs other ESP32 chips →

Compute

MCU

ESP32-S3

Clock

240 MHz

SRAM · Flash

512 KB · 8MB

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 · 2

PWM

8 channels

Power

USB

USB-C

Serial

Native (CDC)

Boot address

0x0

Electrical

Input

5V USB · 3.7V LiPo

Consumption

~100µA sleep

Regulator

AP2112K-3.3

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 No 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

Inside sits the ESP32-S3 - a dual-core Xtensa with vector extensions suited to AI workloads.

At $17.50 it's cheaper than most ESP32-S3 boards, which usually run around $29.

Around the module: 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.

8MB flash, no PSRAM (sibling of the 4MB-flash + 2MB-PSRAM ESP32-S3 Feather)
Early units shipped with an LC709203F fuel gauge instead of the MAX17048

Where to buy

prices are typical street prices

Adafruit Feather ESP32-S3 No PSRAM

$17.50per unit, typical

Resources

Board datasheet learn.adafruit.com↗ ESP32-S3 datasheet espressif.com↗ Adafruit product page adafruit.com↗Adafruit learn guide learn.adafruit.com↗

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