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.
Adafruit Feather ESP32-S3 No PSRAM 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 | safe | - | |
| 20 | 35 | MOSIPWM | safe | spi | |
| 21 | 36 | SCKPWM | safe | spi | |
| 22 | 37 | MISOPWM | safe | spi | |
| 23 | 38 | RXPWM | uart | uart | |
| 24 | 39 | TXPWM | strapping | uart | |
| 25 | 42 | SSPWM | strapping | spi |
Start with these
16 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
9 pins · 4 things to knowSDAGPIO3 Bootstrapping pin (controls JTAG signal source) Strapping
Sampled at reset to select JTAG interface (USB Serial/JTAG controller vs. external pins). Improper use can disable external JTAG or alter debug interface.
A10GPIO9A11GPIO10A12GPIO11A13GPIO12LED_BUILTINGPIO13A4GPIO14 General-purpose SPI2 (FSPI) IO MUX pins Other
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.
- A10General-purpose SPI2 (FSPI) IO MUX pin - hold/data line (FSPIHD)
- A11General-purpose SPI2 (FSPI) IO MUX pin - chip select (FSPICS0)
- A12General-purpose SPI2 (FSPI) IO MUX pin - data in (FSPID)
- A13General-purpose SPI2 (FSPI) IO MUX pin - clock (FSPICLK)
- LED_BUILTINGeneral-purpose SPI2 (FSPI) IO MUX pin - data out (FSPIQ)
- A4General-purpose SPI2 (FSPI) IO MUX pin - write-protect/data line (FSPIWP)
TXGPIO39 JTAG test clock (MTCK); IO MUX alternates CLK_OUT3 and SUBSPICS1 (chip select on the alternative SUBSPI memory bus, unused on standard modules) JTAG
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.
SSGPIO42 JTAG test mode select pin (MTMS) JTAG
Default JTAG TMS signal for debugging. Using this pin for other purposes will disable the JTAG interface (unless JTAG is rerouted to USB).
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 12 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
// 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);
}[env:adafruit_feather_esp32s3_nopsram]
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: esp32s3
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).Specifications
ESP32-S3 · 52.3 × 22.7 mm · vs other ESP32 chips →Dimensions
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 pricesResources
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