M5Stack-CoreInk
ESP32-based e-paper display with an onboard RTC and battery - designed for always-on status dashboards and low-power UIs.
M5Stack-CoreInk Pinout
24 pins · 2.54 mm pitch| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 1 | TXPWM | uart | uart | |
| 2 | 2 | G2PWM | strapping | - | |
| 3 | 3 | RXPWM | uart | uart | |
| 4 | 5 | G5PWM | strapping | - | |
| 5 | 9 | SSPWM | strapping | spi | |
| 6 | 10 | G10PWM | strapping | - | |
| 7 | 12 | G12PWM | strapping | - | |
| 8 | 13 | RX2G13PWM | strapping | - | |
| 9 | 14 | TX2G14PWM | strapping | - | |
| 10 | 18 | SCKPWM | safe | spi | |
| 11 | 19 | G19PWM | safe | - | |
| 12 | 21 | G21PWM | safe | - | |
| 13 | 22 | G22PWM | safe | - | |
| 14 | 23 | MOSIPWM | safe | spi | |
| 15 | 25 | G25DAC1PWM | safe | dac | |
| 16 | 26 | G26DAC2PWM | safe | dac | |
| 17 | 32 | SDAG32PWM | safe | i2c | |
| 18 | 33 | SCLG33PWM | safe | i2c | |
| 19 | 34 | MISO | strapping | spi | |
| 20 | 35 | ADC1 | strapping | - | |
| 21 | 36 | G36ADC2 | strapping | - | |
| 22 | 37 | G37 | strapping | - | |
| 23 | 38 | G38 | strapping | - | |
| 24 | 39 | G39 | strapping | - |
Start with these
9 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
13 pins · 10 things to knowTXGPIO1 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.
G2GPIO2 Bootstrapping pin (must be low or floating at reset); internal pull-down. Strapping
If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure.
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.
G5GPIO5 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.
G12GPIO12 Bootstrapping pin; JTAG TDI; sets flash voltage (VDD_SDIO); also HSPIQ (flash data line). Strapping
Keep LOW during boot (internal PD); pulling HIGH at reset selects 1.8V flash mode, causing flash brownout if 3.3V flash is used.
RX2GPIO13 JTAG clock pin (TCK); also ADC2 channel 4 / Touch4 input. JTAG
Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed.
TX2GPIO14 JTAG mode select pin (TMS); also HSPI CLK and PWM-capable GPIO. JTAG
Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot.
MISOGPIO34 Input-only GPIO (no output driver); ADC1 channel 6. Other
Cannot be used as output (no drive capability); only suitable for analog/digital input.
ADC1GPIO35G37GPIO37G38GPIO38G39GPIO39 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.
- G38Input-only GPIO (no output); ADC1 channel 2.
- G39Input-only GPIO (no output); ADC1 channel 3, Hall sensor VN.
G36GPIO36 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 knowSSGPIO9G10GPIO10 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.
- SSConnected to SPI flash/PSRAM data 2 (SD2, flash HOLD).
- G10Connected to SPI flash/PSRAM data 3 (SD3, flash WP).
The M5Stack-CoreInk pinout brings out 24 GPIO pins at a 2.54 mm pitch - 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, SCK, G19, G21, G22 and 5 more are free of any such role - the safest first picks. 13 of the exposed pins carry boot-time or system duties on the ESP32 (TX, G2, RX and 10 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 GPIO18 - wire an LED and resistor to it
void setup() {
pinMode(18, OUTPUT);
}
void loop() {
digitalWrite(18, HIGH); delay(500);
digitalWrite(18, LOW); delay(500);
}[env:m5stack-coreink]
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 - GPIO18
output:
- platform: gpio
pin: 18
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 · 56 × 40 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.
Onboard you'll find an ePaper 1.54" 200x200 display, a Grove connector, a BM8563 RTC, a buzzer, battery charging, status LEDs (Status) and Power/Reset/Programmable/Dial switch buttons.
- Built-in 390mAh LiPo battery
- Some units ship with a CH9102 USB-serial chip instead of the CP2104
Resources
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