M5Stick-C

Tiny ESP32 wearable-ready dev kit with display, IMU, and battery - perfect for on-the-go sensor projects.

USB-C
M5Stick-C board
48.2 × 25.5 mm
ESP32
MCU
240MHz
clock
4MB
flash
520KB
SRAM
16· Two 12-bit, 18 Channels ADC
GPIO
BLE 4.2+ WiFi
radio
On this page

Pinout

16 pins
View:
M5Stick-C pinout diagram
PinGPIOLabelsStatusCapabilitiesNotes
10G0strapping-
21TXPWMuartuart
33RXPWMuartuart
45SSPWMstrappingspi
59G9PWMstrapping-
610G10PWMstrapping-
713SCKPWMstrappingspi
815MOSIPWMstrappingspi
925DAC1PWMsafedac
1026G26DAC2PWMsafedac
1132RXD2SDAG32PWMsafei2c
1233TXD2SCLG33PWMsafei2c
1335ADC1strapping-
1436MISOG36ADC2strappingspi
1537G37strapping-
1639G39strapping-

Start with these

4 pins with no boot or system involvement
DAC1PWMG26DAC2RXD2SDATXD2SCL

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
PinLabelWhat to knowRole
G0GPIO0Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode.Strapping
SSGPIO5Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot.Strapping
SCKMTCK (GPIO13)Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed.Other
MOSIMTDO (GPIO15)Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change.Strapping
ADC1GPIO35Cannot be used as output; only suitable for input.Other
MISOGPIO36 (SENSOR_VP)Cannot be used as output; only suitable for input (e.g., analog read).Other
G37GPIO37 (SENSOR_CAPP)Cannot be used as output; only suitable for input.Other
G39GPIO39 (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
PinLabelWhat to knowRole
TXU0TXD (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
RXU0RXD (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
G9GPIO9 (Flash SD2)Used by internal flash/PSRAM; typically not exposed on modules, avoid using as GPIO.Flash
G10GPIO10 (Flash SD3)Used by internal flash/PSRAM; typically not exposed on modules, avoid using as GPIO.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 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 minutes
Tool:
1
Connect over USB
Serial chip: CP2104. Not detected? Hold BOOT while plugging in.
2
Flash with your tool
Arduino IDE, PlatformIO, ESPHome or esptool - copy the settings on the right.
3
Verify it runs
The blink example uses GPIO25 - swap for your board's LED pin if different.
Tools → Board settings Copy
Board:            M5stick C
Flash Size:       4MB · DIO
Upload Speed:     921600

// blink
pinMode(25, OUTPUT);
digitalWrite(25, LOW);   // on (often inverted)
platformio.ini Copy
[env:m5stick-c]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600
device.yaml Copy
esp32:
  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_out
shell Copy
esptool.py --chip esp32 --port /dev/ttyACM0 \
  write_flash 0x0 firmware.bin
Build details: sketch space 1310720 B · data 327680 B · DIO

Specifications

ESP32 · 48.2 × 25.5 mm
Compute
MCU
ESP32
Clock
240 MHz
SRAM · Flash
520 KB · 4MB
Radio
Wi-Fi
802.11 b/g/n
Bluetooth
4.2 LE
Antenna
PCB
I/O
GPIO · ADC
16 · Two 12-bit, 18 Channels
UART · I²C · SPI
3 · 2 · 4
PWM
16 channels
Power
USB
USB-C
Serial
CP2104
Boot address
0x1000
Display
Screen
TFT · 0.96" · 80x160
Driver
ST7735S
Touch
No
Flashing
Upload · OTA
esptool_py · esp_ota
Flash · Boot mode
DIO · DIO
Sketch · Data
1.25 MB · 320 KB
25.5 mm48.2 mm
48.2 × 25.5 mm
The M5Stick-C uses esptool_py for firmware uploads, esp_ota for over-the-air (OTA) updates. Flash mode is DIO with DIO 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 - 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 prices
M5Stick-C
M5Stick-C
$9.95per unit, typical

Resources

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