SparkFun ESP32-S2 Thing Plus

Feather-compatible ESP32-S2 board with USB and LiPo - ideal for secure IoT and hardware prototyping.

USB-C
SparkFun ESP32-S2 Thing Plus board
64.8 × 22.9 mm
ESP32-S2
MCU
240MHz
clock
4MB
flash
320KB
SRAM
28· 15 ADC
GPIO
Wi-Fi
radio
On this page

SparkFun ESP32-S2 Thing Plus Pinout

28 pins · 2.54 mm pitch
PinGPIOLabelsStatusCapabilitiesNotes
11SDAT1PWMsafetouch · i2c
22SCLT2PWMsafetouch · i2c
33T3PWMsafetouch
44T4PWMsafetouch
55A5T5PWMsafeadc · touch
66T6PWMsafetouch
77A4A6T7PWMsafeadc · touch
88A7T8PWMsafeadc · touch
99A3A8T9PWMstrappingadc · touch
1010A9T10PWMstrappingadc · touch
1111A10T11PWMstrappingadc · touch
1212A11T12PWMstrappingadc · touch
1313LED_BUILTINA12T13PWMstrappingadc · touch
1414A2A13T14PWMstrappingadc · touch
1515A14PWMstrappingadc
1616A15PWMstrappingadc
1717A0A16DAC1PWMsafeadc · dac
1818A1A17DAC2PWMsafeadc · dac
1919A18PWMuartadc
2020A19PWMuartadc
2133RX1PWMsafe-
2234TX1PWMsafe-
2335MOSIPWMsafespi
2436SCKPWMsafespi
2537MISOPWMsafespi
2642SSPWMstrappingspi
2743TXPWMuartuart
2844RXPWMuartuart
28 GPIOs broken out 17 free · 9 need care · 2 to avoid

Start with these

17 pins with no boot or system involvement
SDAGPIO1SCLGPIO2T3GPIO3T4GPIO4A5GPIO5T6GPIO6A4GPIO7A7GPIO8A0GPIO17A1GPIO18RX1GPIO33TX1GPIO34MOSIGPIO35SCKGPIO36MISOGPIO37TXGPIO43RXGPIO44

Freely 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 know
A3GPIO9A9GPIO10A10GPIO11A11GPIO12LED_BUILTINGPIO13A2GPIO14 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 does not restrict it, so it is only taken if your board wires flash, an SD card or a display to FSPI.

  • A3General-purpose SPI2 (FSPI) IO MUX pin - hold/data line (FSPIHD)
  • A9General-purpose SPI2 (FSPI) IO MUX pin - chip select (FSPICS0)
  • A10General-purpose SPI2 (FSPI) IO MUX pin - data in (FSPID)
  • A11General-purpose SPI2 (FSPI) IO MUX pin - clock (FSPICLK)
  • LED_BUILTINGeneral-purpose SPI2 (FSPI) IO MUX pin - data out (FSPIQ)
  • A2General-purpose SPI2 (FSPI) IO MUX pin - write-protect/data line (FSPIWP)
A14GPIO15 32.768 kHz RTC crystal oscillator positive input (XTAL_32K_P); also functions as GPIO15 (U0RTS, ADC2_CH4). Other

If an external 32 kHz crystal is used for RTC, this pin is dedicated to the crystal and cannot be used as GPIO.

A15GPIO16 32.768 kHz RTC crystal negative input (XTAL_32K_N); also GPIO16 (U0CTS, ADC2_CH5). Other

If using an external 32 kHz crystal, this pin is connected to the crystal and should not be used as general I/O.

SSGPIO42 JTAG test mode select pin (MTMS); also GPIO42. JTAG

JTAG TMS pin; should not be repurposed if JTAG debugging or programming via JTAG is required.

Only if you know the tricks

2 pins · 2 things to know
A18GPIO19 USB OTG D- line (full-speed USB data -); also available as GPIO19/RTC_GPIO19 and ADC2 channel 8. USB

Used for USB communication; using this pin as general GPIO can interfere with USB functionality.

A19GPIO20 USB OTG D+ line (full-speed USB data +); also serves as GPIO20/RTC_GPIO20 and ADC2 channel 9. USB

Dedicated to USB interface; repurposing as GPIO may disrupt USB connectivity.

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.

All 28 pins on the SparkFun ESP32-S2 Thing Plus are usable GPIO, spaced at the standard 2.54 mm pitch.

Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO1 and SCL on GPIO2; 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 15 ADC-capable pins for sensors and battery monitoring, 14 capacitive-touch inputs and 2 true DAC outputs.

9 of the exposed pins carry boot-time or system duties on the ESP32-S2 (A3, A9, A10 and 6 more) - check the guidance above before wiring anything to them. SDA, SCL, T3, T4 and 13 more are free of any such role - the safest first picks.

Getting started

flash your first firmware in ~2 minutes
Tool:
1
Connect over USB
Uses a CP2102 bridge - install the CP210x driver if no port appears. Not detected? Hold BOOT while plugging in.
2
Match & flash
Set the Tools options shown, then click Upload.
3
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: "ESP32S2 Dev Module"▸
Flash Size: "4MB (32Mb)"▸
Flash Mode: "QIO"▸
Partition Scheme: "Default 4MB with spiffs (1.2MB APP/1.5MB SPIFFS)" (default)▸
Upload Speed: "921600"▸
▸ every other Tools option - leave at default
Board: ESP32S2 Dev Module
Flash Size: 4MB (32Mb)
Flash Mode: QIO
Partition Scheme: Default 4MB with spiffs (1.2MB APP/1.5MB SPIFFS)
Upload Speed: 921600
Find it: Tools ▸ Board ▸ ESP32 Arduino ▸ ESP32S2 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-s2-saola-1⧉ copy
platformio.ini Copy
[env:sparkfun_esp32s2_thing_plus]
platform = espressif32
board = esp32-s2-saola-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600
Find it: PlatformIO Home ▸ Boards, search esp32-s2-saola-1 - or type it after board =.
board to selectesp32-s2-saola-1⧉ copy
device.yaml Copy
esp32:
  board: esp32-s2-saola-1
  variant: esp32s2
  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-s2-saola-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 esp32s2 --port /dev/ttyACM0 \
  --baud 921600 write_flash 0x1000 firmware.bin
--port = your /dev/tty* (macOS/Linux) or COMx (Windows).
Build details: sketch space 1310720 B · data 327680 B · QIO

Specifications

ESP32-S2 · 64.8 × 22.9 mm · vs other ESP32 chips →
Compute
MCU
ESP32-S2
Clock
240 MHz
SRAM · Flash
320 KB · 4MB
Radio
Wi-Fi
802.11 b/g/n 2.4 GHz
Bluetooth
-
Antenna
PCB
I/O
GPIO · ADC
28 · 15
UART · I²C · SPI
2 · 2 · 2
PWM
8 channels
Power
USB
USB-C
Serial
CP2102
Boot address
0x1000
Electrical
Input
5V USB-C · LiPo
Consumption
-
Regulator
-
Flashing
Upload · OTA
esptool_py · esp_ota
Flash · Boot mode
QIO · QIO
Sketch · Data
1.25 MB · 320 KB

Dimensions

22.9 mm64.8 mm
64.8 × 22.9 mm · pin pitch 2.54 mm
The SparkFun ESP32-S2 Thing Plus uses esptool_py for firmware uploads, esp_ota for over-the-air (OTA) updates. Flash mode is QIO 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-S2 - a single-core Xtensa with native USB-OTG and no Bluetooth.

At $24.50 it's on the expensive side for an ESP32-S2 board - most land around $20.

Around the module: a Qwiic connector, battery charging (MCP73831) via JST-PH 2.0, status LEDs (Status (IO18), Charge) and Reset/Boot (IO0) buttons.

Where to buy

prices are typical street prices
SparkFun ESP32-S2 Thing Plus
SparkFun ESP32-S2 Thing Plus
$24.50per unit, typical

Resources

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