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Crabik Slot ESP32-S3
A modular ESP32-S3 development board designed for slot-based expansion and customization.
50.8 × 50.8 mm
ESP32-S3
MCU
240MHz
clock
8MB
flash
512KB
SRAM
31· Two 12-bit, 20 Channels ADC
GPIO
BLE 5.0+ WiFi
radio
Pinout
42 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 0 | BOOT_BTN | strapping | - | |
| 2 | 1 | S1T1PWM | safe | touch | |
| 3 | 2 | S3T2PWM | safe | touch | |
| 4 | 3 | S7T3PWM | strapping | touch | |
| 5 | 4 | S8T4PWM | safe | touch | |
| 6 | 5 | S9T5PWM | safe | touch | |
| 7 | 6 | S10T6PWM | safe | touch | |
| 8 | 7 | S11T7PWM | safe | touch | |
| 9 | 8 | S12T8PWM | safe | touch | |
| 10 | 9 | S13T9PWM | strapping | touch | |
| 11 | 10 | S14T10PWM | strapping | touch | |
| 12 | 11 | S4T11PWM | strapping | touch | |
| 13 | 12 | S2T12PWM | strapping | touch | |
| 14 | 13 | SDAPWM | strapping | i2c | |
| 15 | 14 | SCLPWM | strapping | i2c | |
| 16 | 15 | EN_TROYKAPWM | safe | - | |
| 17 | 16 | LIPO_ALERTPWM | safe | - | |
| 18 | 17 | S5PWM | safe | - | |
| 19 | 18 | S6PWM | safe | - | |
| 20 | 19 | USB_DNPWM | uart | - | |
| 21 | 20 | USB_DPPWM | uart | - | |
| 22 | 21 | LED_BUILTINPWM | safe | - | |
| 23 | 33 | S19PWM | strapping | - | |
| 24 | 34 | S20PWM | strapping | - | |
| 25 | 35 | MOSIPWM | strapping | spi | |
| 26 | 36 | SCKPWM | strapping | spi | |
| 27 | 37 | MISOPWM | strapping | spi | |
| 28 | 45 | S15PWM | strapping | - | |
| 29 | 46 | S16 | strapping | - | |
| 30 | 47 | S18 | strapping | - | |
| 31 | 48 | S17 | strapping | - | |
| 32 | - | TX | uart | uart | |
| 33 | - | RX | uart | uart | |
| 34 | - | D | safe | - | |
| 35 | - | C | safe | - | |
| 36 | - | DO | safe | - | |
| 37 | - | DI | safe | - | |
| 38 | - | CLK | safe | - | |
| 39 | - | CS1 | safe | - | |
| 40 | - | CS2 | safe | - | |
| 41 | - | SS | safe | spi | |
| 42 | - | USER_LED | safe | - |
Start with these
12 pins with no boot or system involvementS1T1S3T2S8T4S9T5S10T6S11T7S12T8EN_TROYKAPWMLIPO_ALERTPWMS5PWMS6PWMLED_BUILTINPWM
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 |
|---|---|---|---|
| BOOT_BTN | GPIO0 | Must be pulled high (default) or low (to enter UART download mode) at reset. Using it for other functions can interfere with boot mode configuration. | Strapping |
| S7 | 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 |
| S13 | FSPIHD | 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. | Other |
| S14 | FSPICS0 | 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. | Other |
| S4 | FSPID | 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. | Other |
| S2 | FSPICLK | 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. | Other |
| SDA | FSPIQ | 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. | Other |
| SCL | FSPIWP | 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. | Other |
| S15 | GPIO45 | Determines flash/PSRAM power voltage (3.3 V vs 1.8 V) at boot. Must match hardware configuration; using as GPIO can upset flash supply setting. | Strapping |
| S16 | GPIO46 | Must be at a defined level during reset (with GPIO0) to select normal or download boot and UART/USB print mode. This pin is input-only (no output drive), so it should be left for its intended strapping function. | Strapping |
| S18 | SPICLK_P | Only the 1.8 V octal parts (ESP32-S3R8V, ESP32-S3R16V) run the differential memory clock here, and on those the pin works at 1.8 V instead of 3.3 V. On the common 3.3 V modules it is a normal GPIO - several devkits drive their RGB LED from GPIO48. | Other |
| S17 | SPICLK_N | Only the 1.8 V octal parts (ESP32-S3R8V, ESP32-S3R16V) run the differential memory clock here, and on those the pin works at 1.8 V instead of 3.3 V. On the common 3.3 V modules it is a normal GPIO - several devkits drive their RGB LED from GPIO48. | Other |
Only if you know the tricks
wired to flash or USB - expect a fight| Pin | Label | What to know | Role |
|---|---|---|---|
| USB_DN | USB_D- | By default connected to the on-chip USB Serial/JTAG controller. Using it as general GPIO without reconfiguring IO MUX will interfere with USB functionality. | USB |
| USB_DP | USB_D+ | By default connected to the on-chip USB Serial/JTAG controller. Using it as general GPIO without reconfiguring IO MUX will interfere with USB functionality. | USB |
| S19 | SPIIO4 (GPIO33) | The datasheet keeps GPIO33-37 for "the higher 4 bits data line interface and DQS interface for the SPI0/1 interface in 8-line SPI mode", so octal-PSRAM modules (N16R8 and friends) consume it and do not break it out. On quad-PSRAM or PSRAM-less parts it is an ordinary GPIO - check which variant your module carries. | Flash |
| S20 | SPIIO5 (GPIO34) | The datasheet keeps GPIO33-37 for "the higher 4 bits data line interface and DQS interface for the SPI0/1 interface in 8-line SPI mode", so octal-PSRAM modules (N16R8 and friends) consume it and do not break it out. On quad-PSRAM or PSRAM-less parts it is an ordinary GPIO - check which variant your module carries. | Flash |
| MOSI | SPIIO6 (GPIO35) | The datasheet keeps GPIO33-37 for "the higher 4 bits data line interface and DQS interface for the SPI0/1 interface in 8-line SPI mode", so octal-PSRAM modules (N16R8 and friends) consume it and do not break it out. On quad-PSRAM or PSRAM-less parts it is an ordinary GPIO - check which variant your module carries. | Flash |
| SCK | SPIIO7 (GPIO36) | The datasheet keeps GPIO33-37 for "the higher 4 bits data line interface and DQS interface for the SPI0/1 interface in 8-line SPI mode", so octal-PSRAM modules (N16R8 and friends) consume it and do not break it out. On quad-PSRAM or PSRAM-less parts it is an ordinary GPIO - check which variant your module carries. | Flash |
| MISO | SPIDQS (GPIO37) | The datasheet keeps GPIO33-37 for "the higher 4 bits data line interface and DQS interface for the SPI0/1 interface in 8-line SPI mode", so octal-PSRAM modules (N16R8 and friends) consume it and do not break it out. On quad-PSRAM or PSRAM-less parts it is an ordinary GPIO - check which variant your module carries. | 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 The Crabik Slot ESP32-S3 breaks out 42 pins in total: 31 GPIO for your project. For peripherals, I²C is mapped to SDA on GPIO13 and SCL on GPIO14, while the…
The Crabik Slot ESP32-S3 breaks out 42 pins in total: 31 GPIO for your project.
For peripherals, I²C is mapped to SDA on GPIO13 and SCL on GPIO14, while the SPI bus (MOSI, MISO, SCK, SS) is broken out in full.
On the analog side there are 12 capacitive-touch inputs.
If you want zero surprises, S1, S3, S8, S9 and 8 more are free of any such role - the safest first picks. 12 of the exposed pins carry boot-time or system duties on the ESP32-S3 (BOOT_BTN, S7, S13 and 9 more).
Getting started
flash your first firmware in ~2 minutes1
Connect over USB
Native USB - shows up as a port right away, no driver needed. 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: "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)" (default)▸
Upload Speed: "921600"▸
▸ every other Tools option - leave at default
Board: 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
Find it: Tools ▸ Board ▸ ESP32 Arduino ▸ ESP32S3 Dev Module
// 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-s3-devkitc-1⧉ copy
[env:crabik_slot_esp32_s3]
platform = espressif32
board = esp32-s3-devkitc-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600Find it: PlatformIO Home ▸ Boards, search
esp32-s3-devkitc-1 - or type it after board =.board to selectesp32-s3-devkitc-1⧉ copy
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_outFind it: search ESPHome's board list for
esp32-s3-devkitc-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.
esptool.py --chip esp32s3 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x0 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Build details: sketch space 1310720 B · data 327680 B · DIO
Specifications
ESP32-S3 · 50.8 × 50.8 mm · vs other ESP32 chips →Compute
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
31 · Two 12-bit, 20 Channels
UART · I²C · SPI
3 · 2 · 2
PWM
8 channels
Power
USB
USB-C
Serial
Native (CDC)
Boot address
0x0
Electrical
Input
5V USB · Li-Po battery
Consumption
-
Regulator
AP2112K-3.3
Flashing
Upload · OTA
esptool_py · esp_ota
Flash · Boot mode
DIO · QIO
Sketch · Data
1.25 MB · 320 KB
50.8 × 50.8 mm · pin pitch 2.54 mm
The Crabik Slot ESP32-S3 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
At its core is the ESP32-S3 - a dual-core Xtensa with vector extensions suited to AI workloads.
31 GPIO are broken out - more than most ESP32-S3 boards, so the pin budget is rarely the constraint.
Onboard you'll find a Qwiic connector, a battery fuel gauge (MAX17048), battery charging (MCP73831) via JST-PH 2.0, status LEDs (User, Charge, Power) and Reset/Boot buttons.
It flashes over native USB - no serial-converter driver needed, which isn't a given among ESP32-S3 boards.
- Four Troyka-format module slots (A-D) for plug-in peripherals
- Dual 3.3V 600mA LDO regulators; second regulator is user-controllable
- Automatic power switching between USB and Li-Po battery
Resources
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