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M5Stack-FIRE
Enhanced Core ESP32 with extra sensors, mic, and IMU - ideal for edge AI and sensor fusion projects.
54 × 54 mm
ESP32
MCU
240MHz
clock
16MB
flash
520KB
SRAM
20· Two 12-bit, 18 Channels ADC
GPIO
BLE 4.2+ WiFi
radio
Pinout
20 pins
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 0 | G0 | strapping | - | |
| 2 | 1 | TXG1PWM | uart | uart | |
| 3 | 2 | G2PWM | strapping | - | |
| 4 | 3 | RXG3PWM | uart | uart | |
| 5 | 5 | SSG5PWM | strapping | spi | |
| 6 | 12 | G12PWM | strapping | - | |
| 7 | 13 | G13PWM | strapping | - | |
| 8 | 15 | G15PWM | strapping | - | |
| 9 | 16 | RXD2G16PWM | strapping | - | |
| 10 | 17 | TXD2G17PWM | strapping | - | |
| 11 | 18 | SCKG18PWM | safe | spi | |
| 12 | 19 | MISOG19PWM | safe | spi | |
| 13 | 21 | SDAG21PWM | safe | i2c | |
| 14 | 22 | SCLG22PWM | safe | i2c | |
| 15 | 23 | MOSIG23PWM | safe | spi | |
| 16 | 25 | G25DAC1PWM | safe | dac | |
| 17 | 26 | G26DAC2PWM | safe | dac | |
| 18 | 34 | G34 | strapping | - | |
| 19 | 35 | G35ADC1 | strapping | - | |
| 20 | 36 | G36ADC2 | strapping | - |
Start with these
7 pins with no boot or system involvementSCKG18MISOG19SDAG21SCLG22MOSIG23G25DAC1G26DAC2
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 |
|---|---|---|---|
| G0 | GPIO0 | Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode. | Strapping |
| G2 | GPIO2 | If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure. | Strapping |
| SS | GPIO5 | Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot. | Strapping |
| G12 | MTDI (GPIO12) | Keep LOW during boot (internal PD); pulling HIGH at reset selects 1.8V flash mode, causing flash brownout if 3.3V flash is used. | Strapping |
| G13 | MTCK (GPIO13) | Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed. | Other |
| G15 | MTDO (GPIO15) | Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change. | Strapping |
| G34 | GPIO34 | Cannot be used as output (no drive capability); only suitable for analog/digital input. | Other |
| G35 | GPIO35 | Cannot be used as output; only suitable for input. | Other |
| G36 | GPIO36 (SENSOR_VP) | Cannot be used as output; only suitable for input (e.g., analog read). | 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 |
| RXD2 | GPIO16 | Connected to internal PSRAM on PSRAM-enabled modules; not usable as GPIO on those modules. | Flash |
| TXD2 | GPIO17 | Connected to internal PSRAM on PSRAM-enabled modules; not usable as GPIO on those modules. | 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 All 20 pins on the M5Stack-FIRE are usable GPIO. Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO21 and SCL on GPIO22; the SPI bus ( MOSI ,…
All 20 pins on the M5Stack-FIRE are usable GPIO.
Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO21 and SCL on GPIO22; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO1 and GPIO3 cover serial logging and flashing.
Beyond plain digital I/O you get 2 true DAC outputs.
9 of the exposed pins carry boot-time or system duties on the ESP32 (G0, G2, SS and 6 more) - check the guidance above before wiring anything to them. SCK, MISO, SDA, SCL and 3 more are free of any such role - the safest first picks.
Getting started
flash your first firmware in ~2 minutes1
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 GPIO18 - swap for your board's LED pin if different.
Board: M5stack Fire
Flash Size: 16MB · DIO
Upload Speed: 921600
// blink
pinMode(18, OUTPUT);
digitalWrite(18, LOW); // on (often inverted)[env:m5stack-fire]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32:
board: esp32dev
variant: m5stack_fire
framework:
type: esp-idf
# blink - GPIO18
output:
- platform: gpio
pin: 18
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesptool.py --chip esp32 --port /dev/ttyACM0 \
write_flash 0x0 firmware.binBuild details: sketch space 6553600 B · data 4521984 B · DIO
Specifications
ESP32 · 54 × 54 mmCompute
MCU
ESP32
Clock
240 MHz
SRAM · Flash
520 KB · 16MB · 8MB (QSPI) PSRAM
Radio
Wi-Fi
802.11 b/g/n
Bluetooth
4.2 LE
Antenna
3D
I/O
GPIO · ADC
20 · 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
LCD · 2.0" · 320x240
Driver
ILI9342C
Touch
No
Flashing
Upload · OTA
esptool_py · esp_ota
Flash · Boot mode
DIO · DIO
Sketch · Data
6.25 MB · 4.31 MB
54 × 54 mm
The M5Stack-FIRE 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 6.25 MB with 4.31 MB available for data.
About this board
Inside sits the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.
At $49.90 it's on the expensive side for an ESP32 board - most land around $20.
Around the module: 8MB (QSPI) PSRAM, an LCD 2.0" 320x240 display, a microSD slot, a microphone, a speaker, an MPU6886 + BMM150 IMU, an addressable RGB LED (GPIO15), battery charging (IP5306) and A/B/C buttons.
- Built-in 500mAh 3.7V LiPo battery
Where to buy
prices are typical street pricesM5Stack-FIRE
$49.90per unit, typical
Resources
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