Department of Alchemy MiniMain ESP32-S2
Minimal ESP32-S2 board with secure features - ideal for embedded development and integration.
Department of Alchemy MiniMain ESP32-S2 Pinout
26 pins| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 1 | NEOPIXEL_NUMPWM | safe | - | |
| 2 | 2 | PIN_SERVOT2PWM | safe | touch | |
| 3 | 3 | SDAPWM | safe | i2c | |
| 4 | 4 | SCLPWM | safe | i2c | |
| 5 | 5 | T5PWM | safe | touch | |
| 6 | 6 | T6PWM | safe | touch | |
| 7 | 8 | A5T8PWM | safe | adc · touch | |
| 8 | 9 | T9PWM | strapping | touch | |
| 9 | 10 | T10PWM | strapping | touch | |
| 10 | 11 | T11PWM | strapping | touch | |
| 11 | 12 | T12PWM | strapping | touch | |
| 12 | 13 | LED_BUILTINT13PWM | strapping | touch | |
| 13 | 14 | A4T14PWM | strapping | adc · touch | |
| 14 | 15 | A3PWM | strapping | adc | |
| 15 | 16 | A2PWM | strapping | adc | |
| 16 | 17 | A1DAC1PWM | safe | adc · dac | |
| 17 | 18 | A0DAC2PWM | safe | adc · dac | |
| 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 | 40 | PIN_ISOLATED_INPUTPWM | strapping | - | |
| 26 | 42 | SSPWM | strapping | spi |
Start with these
15 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
11 pins · 6 things to knowT9GPIO9T10GPIO10T11GPIO11T12GPIO12LED_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 does not restrict it, so it is only taken if your board wires flash, an SD card or a display to FSPI.
- T9General-purpose SPI2 (FSPI) IO MUX pin - hold/data line (FSPIHD)
- T10General-purpose SPI2 (FSPI) IO MUX pin - chip select (FSPICS0)
- T11General-purpose SPI2 (FSPI) IO MUX pin - data in (FSPID)
- T12General-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)
A3GPIO15 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.
A2GPIO16 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.
TXGPIO39 JTAG test clock pin (MTCK); also usable as GPIO39 or as a clock output (CLK_OUT3). JTAG
Used for JTAG debugging interface; using this pin for other purposes will disable JTAG clock input.
PIN_ISOLATED_INPUTGPIO40 JTAG test data-out pin (MTDO); also GPIO40, supports CLK_OUT2. JTAG
Part of JTAG interface (TDO); should be avoided as GPIO if JTAG debugging is needed.
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.
The Department of Alchemy MiniMain ESP32-S2 pinout brings out 26 GPIO pins - 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 6 ADC-capable pins for sensors and battery monitoring, 10 capacitive-touch inputs and 2 true DAC outputs.
If you want zero surprises, NEOPIXEL_NUM, PIN_SERVO, SDA, SCL and 11 more are free of any such role - the safest first picks. 11 of the exposed pins carry boot-time or system duties on the ESP32-S2 (T9, T10, T11 and 8 more).
Getting started
flash your first firmware in ~2 minutesBoard: ESP32S2 Dev Module USB CDC On Boot: Enabled Flash Size: 4MB (32Mb) Flash Mode: QIO PSRAM: QSPI PSRAM Partition Scheme: Default 4MB with spiffs (1.2MB 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:department_of_alchemy_minimain_esp32s2]
platform = espressif32
board = esp32-s2-saola-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600
board_build.arduino.memory_type = qio_qspi
build_flags = -DBOARD_HAS_PSRAMesp32-s2-saola-1 - or type it after board =.esp32:
board: esp32-s2-saola-1
variant: esp32s2
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_outesp32-s2-saola-1 (same ids as PlatformIO).esptool.py --chip esp32s2 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x1000 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Specifications
ESP32-S2 · vs other ESP32 chips →About this board
At its core is the ESP32-S2 - a single-core Xtensa with native USB-OTG and no Bluetooth.
Onboard you'll find 2MB (QSPI) PSRAM and an addressable RGB LED (GPIO33).
It flashes over native USB - no serial-converter driver needed, which isn't a given among ESP32-S2 boards.
- ESP32-S2-MINI-1 module
- Optoisolated 12V trigger input
- Servo header (3-pin, 2.54mm)
- No battery / LiPo support
Resources
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