UM PROS3
An advanced ESP32-S3 board by Unexpected Maker, featuring ESD protection, castellated headers, and extensive Flash and PSRAM, suitable for professional applications.
UM PROS3 Pinout
24 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 1 | A0T1PWM | safe | adc · touch | |
| 2 | 2 | A1T2PWM | safe | adc · touch | |
| 3 | 3 | A2T3PWM | strapping | adc · touch | |
| 4 | 4 | A3T4PWM | safe | adc · touch | |
| 5 | 5 | A4T5PWM | safe | adc · touch | |
| 6 | 6 | A5T6PWM | safe | adc · touch | |
| 7 | 7 | A6T7PWM | safe | adc · touch | |
| 8 | 8 | SDAA7T8PWM | safe | adc · touch · i2c | |
| 9 | 9 | SCLA8T9PWM | strapping | adc · touch · i2c | |
| 10 | 10 | VBAT_SENSEPWM | strapping | - | |
| 11 | 12 | A11T12PWM | strapping | adc · touch | |
| 12 | 13 | A12T13PWM | strapping | adc · touch | |
| 13 | 14 | A13T14PWM | strapping | adc · touch | |
| 14 | 15 | A14PWM | safe | adc | |
| 15 | 16 | A15PWM | safe | adc | |
| 16 | 17 | RGB_PWRLDO2PWM | safe | - | |
| 17 | 18 | RGB_DATAPWM | safe | - | |
| 18 | 33 | VBUS_SENSEPWM | safe | - | |
| 19 | 34 | SSPWM | safe | spi | |
| 20 | 35 | MOSISDOPWM | safe | spi | |
| 21 | 36 | SCKPWM | safe | spi | |
| 22 | 37 | MISOSDIPWM | safe | spi | |
| 23 | 43 | TXPWM | uart | uart | |
| 24 | 44 | RXPWM | uart | uart |
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
8 pins · 4 things to knowA2GPIO3 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.
SCLGPIO9VBAT_SENSEGPIO10A11GPIO12A12GPIO13A13GPIO14 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.
- SCLGeneral-purpose SPI2 (FSPI) IO MUX pin - hold/data line (FSPIHD)
- VBAT_SENSEGeneral-purpose SPI2 (FSPI) IO MUX pin - chip select (FSPICS0)
- A11General-purpose SPI2 (FSPI) IO MUX pin - clock (FSPICLK)
- A12General-purpose SPI2 (FSPI) IO MUX pin - data out (FSPIQ)
- A13General-purpose SPI2 (FSPI) IO MUX pin - write-protect/data line (FSPIWP)
TXGPIO43 UART0 transmit pin (U0TXD), default serial console TX UART
Used for bootloader output and UART console logs. If repurposed, you will lose the default serial output (and programming via UART0).
RXGPIO44 UART0 receive pin (U0RXD), default serial console RX UART
Used for bootloader input (download mode via serial). If repurposed, you cannot use the default UART0 download mode for programming the chip.
All 24 pins on the UM PROS3 are usable GPIO, spaced at the standard 2.54 mm pitch.
Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO8 and SCL on GPIO9; 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 14 ADC-capable pins for sensors and battery monitoring and 12 capacitive-touch inputs.
8 of the exposed pins carry boot-time or system duties on the ESP32-S3 (A2, SCL, VBAT_SENSE and 5 more) - check the guidance above before wiring anything to them. A0, A1, A3, A4 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: 16MB (128Mb) Flash Mode: QIO PSRAM: QSPI PSRAM Partition Scheme: 16M Flash (3MB APP/9.9MB FATFS) 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:pros3]
platform = espressif32
board = esp32-s3-devkitc-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600
board_build.arduino.memory_type = qio_qspi
build_flags = -DBOARD_HAS_PSRAMesp32-s3-devkitc-1 - or type it after board =.esp32:
board: esp32-s3-devkitc-1
variant: esp32s3
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-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 · 53 × 17.8 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.
The $29.95 price tag is typical for an ESP32-S3 board.
Around the module: 8MB (QSPI) PSRAM, a STEMMA QT connector, an addressable RGB LED (GPIO18), battery charging (TP4065) via PicoBlade, status LEDs (Power, Charge) and Reset/Boot buttons.
It flashes over native USB - no serial-converter driver needed, which isn't a given among ESP32-S3 boards.
- USB-C with back-feed protection
- USB ESD protection (USBLC6-2P6)
- Dual 700mA 3.3V LDO regulators (NCP167); LDO2 user-controlled, auto-shuts down in deep sleep
- 3D high-gain (Fractus) chip antenna
- STEMMA QT / Qwiic powered from LDO1
- Castellated edge + through-hole headers
- LiPo charging ~330mA via TP4065
Where to buy
prices are typical street pricesResources
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