No
No
N/A
Adafruit Feather ESP32-S3 No PSRAM
Similar to the previous model but without PSRAM, offering 8MB Flash and ideal for applications not requiring large memory buffers.
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
| 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 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.
3 of the exposed pins carry boot-time or system duties on the ESP32-S3 (SDA, TX and SS) - check the guidance above before wiring anything to them. NEOPIXEL_NUM, SCL, A8, A9 and 7 more are free of any such role - the safest first picks.
Getting started
flash your first firmware in ~2 minutes1
Connect over USB
Native USB - no driver, no serial chip. Not detected? Hold BOOT while plugging in.
2
Flash with your tool
Arduino IDE, PlatformIO, ESPHome or esptool - copy the settings on the right.
3
Verify it runs
The blink example uses GPIO1 - swap for your board's LED pin if different.
Board: Adafruit Feather Esp32s3 Nopsram
USB CDC On Boot: Enabled
Flash Size: 8MB · DIO
Upload Speed: 921600
// blink
pinMode(1, OUTPUT);
digitalWrite(1, LOW); // on (often inverted)[env:adafruit_feather_esp32s3_nopsram]
platform = espressif32
board = esp32-s3-devkitc-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32:
board: esp32-s3-devkitc-1
variant: adafruit_feather_esp32s3_nopsram
framework:
type: esp-idf
# blink - GPIO1
output:
- platform: gpio
pin: 1
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesptool.py --chip esp32s3 --port /dev/ttyACM0 \
write_flash 0x0 firmware.binBuild 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 · 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 · 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 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 $30.
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 pricesAdafruit Feather ESP32-S3 No PSRAM
$17.50per unit, typical
Resources
Similar boards
