M5Stick-C
Tiny ESP32 wearable-ready dev kit with display, IMU, and battery - perfect for on-the-go sensor projects.
Pinout
16 pins
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 0 | G0 | strapping | - | |
| 2 | 1 | TXPWM | uart | uart | |
| 3 | 3 | RXPWM | uart | uart | |
| 4 | 5 | SSPWM | strapping | spi | |
| 5 | 9 | G9PWM | strapping | - | |
| 6 | 10 | G10PWM | strapping | - | |
| 7 | 13 | SCKPWM | strapping | spi | |
| 8 | 15 | MOSIPWM | strapping | spi | |
| 9 | 25 | DAC1PWM | safe | dac | |
| 10 | 26 | G26DAC2PWM | safe | dac | |
| 11 | 32 | RXD2SDAG32PWM | safe | i2c | |
| 12 | 33 | TXD2SCLG33PWM | safe | i2c | |
| 13 | 35 | ADC1 | strapping | - | |
| 14 | 36 | MISOG36ADC2 | strapping | spi | |
| 15 | 37 | G37 | strapping | - | |
| 16 | 39 | G39 | strapping | - |
Start with these
4 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
sampled at boot or shared with debug/serial| Pin | Label | What to know | Role |
|---|---|---|---|
| G0 | GPIO0 | Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode. | Strapping |
| SS | GPIO5 | Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot. | Strapping |
| SCK | MTCK (GPIO13) | Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed. | Other |
| MOSI | MTDO (GPIO15) | Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change. | Strapping |
| ADC1 | GPIO35 | Cannot be used as output; only suitable for input. | Other |
| MISO | GPIO36 (SENSOR_VP) | Cannot be used as output; only suitable for input (e.g., analog read). | Other |
| G37 | GPIO37 (SENSOR_CAPP) | Cannot be used as output; only suitable for input. | Other |
| G39 | GPIO39 (SENSOR_VN) | Cannot be used as output; only suitable for input. | Other |
Only if you know the tricks
wired to flash or USB - expect a fight| Pin | Label | What to know | Role |
|---|---|---|---|
| TX | U0TXD (GPIO1) | Connected to on-board USB-UART for uploading and logs; drives serial output at boot, so using as GPIO can disrupt programming or console. | USB |
| RX | U0RXD (GPIO3) | Used for receiving data from USB-UART (programming); also pulled HIGH at boot for console communication, so using as GPIO can disrupt uploads. | USB |
| G9 | GPIO9 (Flash SD2) | Used by internal flash/PSRAM; typically not exposed on modules, avoid using as GPIO. | Flash |
| G10 | GPIO10 (Flash SD3) | Used by internal flash/PSRAM; typically not exposed on modules, avoid using as GPIO. | Flash |
Pinout notes The M5Stick-C pinout brings out 16 GPIO pins - every one of them usable in your project. For peripherals, I²C is mapped to SDA on GPIO32 and SCL on GPIO33; the…
The M5Stick-C pinout brings out 16 GPIO pins - every one of them usable in your project.
For peripherals, I²C is mapped to SDA on GPIO32 and SCL on GPIO33; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO1 and GPIO3 cover serial logging and flashing.
On the analog side there are 2 true DAC outputs.
If you want zero surprises, DAC1, G26, RXD2 and TXD2 are free of any such role - the safest first picks. 8 of the exposed pins carry boot-time or system duties on the ESP32 (G0, SS, SCK and 5 more).
Getting started
flash your first firmware in ~2 minutesBoard: M5stick C
Flash Size: 4MB · DIO
Upload Speed: 921600
// blink
pinMode(25, OUTPUT);
digitalWrite(25, LOW); // on (often inverted)[env:m5stick-c]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32:
board: esp32dev
variant: m5stick_c
framework:
type: esp-idf
# blink - GPIO25
output:
- platform: gpio
pin: 25
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesptool.py --chip esp32 --port /dev/ttyACM0 \
write_flash 0x0 firmware.binSpecifications
ESP32 · 48.2 × 25.5 mmAbout this board
At its core is the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.
Expect to pay about $9.95 - less than the ~$20 most ESP32 boards go for.
Only 16 GPIO are broken out, where most ESP32 boards manage about 24 - worth checking the pinout covers what you need.
Onboard you'll find a TFT 0.96" 80x160 display, a Grove connector, a microphone (SPM1423), an MPU6886 IMU, a BM8563 RTC, an IR transceiver, battery charging (AXP192) and BtnA/BtnB/Power buttons.
- 95mAh LiPo battery
- AXP192 PMIC for power management and battery gauge
- Early units shipped with SH200Q IMU (later revisions use MPU6886)
Where to buy
prices are typical street pricesResources
Similar boards
