M5Stick-C
Tiny ESP32 wearable-ready dev kit with display, IMU, and battery - perfect for on-the-go sensor projects.
M5Stick-C 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
10 pins · 8 things to knowG0GPIO0 Bootstrapping pin (enter bootloader when low); internal pull-up. Strapping
Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode.
TXGPIO1 Default UART0 TX pin for USB-serial programming and console. UART
Connected to on-board USB-UART for uploading and logs; drives serial output at boot, so using as GPIO can disrupt programming or console.
RXGPIO3 Default UART0 RX pin for USB-serial programming (console input). UART
Used for receiving data from USB-UART (programming); also pulled HIGH at boot for console communication, so using as GPIO can disrupt uploads.
SSGPIO5 Bootstrapping pin; internal pull-up; VSPI CS0 (default SPI chip-select); acts as FSPIWP (flash write-protect) on internal-flash variants. Strapping
Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot.
SCKGPIO13 JTAG clock pin (TCK); also ADC2 channel 4 / Touch4 input. JTAG
Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed.
MOSIGPIO15 Bootstrapping pin; JTAG TDO; controls UART0 boot log output; also HSPICS0 (secondary SPI CS). Strapping
Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change.
ADC1GPIO35G37GPIO37G39GPIO39 Input-only GPIOs with ADC1 channels - no output driver Other
Cannot be used as output; only suitable for input.
- ADC1Input-only GPIO (no output driver); ADC1 channel 7.
- G37Input-only GPIO (no output); ADC1 channel 1.
- G39Input-only GPIO (no output); ADC1 channel 3, Hall sensor VN.
MISOGPIO36 Input-only GPIO (no output); ADC1 channel 0, Hall sensor VP. Other
Cannot be used as output; only suitable for input (e.g., analog read).
Only if you know the tricks
2 pins · 1 thing to knowG9GPIO9G10GPIO10 SPI flash/PSRAM data lines SD2 and SD3 (flash HOLD and WP) Flash
Used by internal flash/PSRAM; typically not exposed on modules, avoid using as GPIO.
- G9Connected to SPI flash/PSRAM data 2 (SD2, flash HOLD).
- G10Connected to SPI flash/PSRAM data 3 (SD3, flash WP).
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. 10 of the exposed pins carry boot-time or system duties on the ESP32 (G0, TX, RX and 7 more).
Getting started
flash your first firmware in ~2 minutesBoard: ESP32 Dev Module Flash Size: 4MB (32Mb) Flash Mode: DIO Partition Scheme: Default 4MB with spiffs (1.2MB APP/1.5MB SPIFFS) Upload Speed: 921600
// toggle GPIO25 - wire an LED and resistor to it
void setup() {
pinMode(25, OUTPUT);
}
void loop() {
digitalWrite(25, HIGH); delay(500);
digitalWrite(25, LOW); delay(500);
}[env:m5stick-c]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32dev - or type it after board =.esp32:
board: esp32dev
variant: esp32
framework:
type: esp-idf
# blink - GPIO25
output:
- platform: gpio
pin: 25
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesp32dev (same ids as PlatformIO).esptool.py --chip esp32 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x1000 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Specifications
ESP32 · 48.2 × 25.5 mm · vs other ESP32 chips →Dimensions
About 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
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