M5Stack CoreInk: specs and pinout
M5Stack CoreInk (K048): an ESP32-PICO-D4 controller with a 1.54 inch 200x200 black and white E-Ink display, buttons, buzzer and a built-in battery.
Specs
| Spec | Value | Source |
|---|---|---|
| SoC | ESP32-PICO-D4, Xtensa 32-bit LX6 dual-core, up to 240 MHz | source p.4, Specifications |
| Memory | 520 KB SRAM, 4 MB flash | source p.4, Specifications |
| Wi-Fi | 2.4 GHz Wi-Fi | source p.4, Specifications |
| Input voltage | 5 V at 500 mA (USB Type-C) | source p.4, Specifications |
| Display | 1.54 inch E-Ink, 200 x 200, 1-bit black and white, SPI (GDEY0154D67) | source p.4, Specifications |
| RTC | BM8563 (I2C, SDA G21, SCL G22) | source p.4, Specifications; p.7, PinMap |
| Battery | 390 mAh at 3.7 V (built-in) | source p.4, Specifications |
| Expansion header | HY2.0-4P (GND, 5V, G32, G33) | source p.7, PinMap |
| Operating temperature | 0 to 60 C | source p.4, Specifications (Operating Temperature) |
| E-Ink refresh time | 2 s full refresh, 0.26 s partial refresh; recommended refresh interval 15 s | source p.4, Specifications (E-Ink Display); p.2 Notes |
| Buttons, LED, buzzer | Programmable button, reset, power; green LED; passive buzzer | source p.4, Specifications |
Power
| Value | Source | |
|---|---|---|
| Supply | 5 V at 500 mA via USB Type-C; built-in 390 mAh battery | source p.4, Specifications |
Pinout
The HY2.0-4P port is the board's own expansion connector (PORT.CUSTOM); the product document gives its pin functions as GND, 5V, G32 and G33.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| G4 | E-Ink BUSY | E-Ink display GDEY0154D67, SPI | source p.6, PinMap | |
| G0 | E-Ink RST | source p.6, PinMap | ||
| G15 | E-Ink D/C | source p.6, PinMap | ||
| G9 | E-Ink CS | source p.6, PinMap | ||
| G18 | E-Ink SCK | source p.6, PinMap | ||
| G23 | E-Ink MOSI | source p.6, PinMap | ||
| G37 | Dial switch up | source p.6, PinMap | ||
| G38 | Dial middle (press) | source p.6, PinMap | ||
| G39 | Dial switch down | source p.6, PinMap | ||
| G5 | User button | source p.6, PinMap | ||
| G10 | LED | green LED | source p.6, PinMap | |
| G2 | Buzzer | passive buzzer | source p.6, PinMap | |
| G12 | Power control (HOLD) | source p.6, PinMap | ||
| G21 | RTC SDA (BM8563) | source p.7, PinMap | ||
| G22 | RTC SCL (BM8563) | source p.7, PinMap | ||
| G1 | USB to TTL RXD (CP2104) | source p.7, PinMap | ||
| G3 | USB to TTL TXD (CP2104) | source p.7, PinMap | ||
| G32 | HY2.0-4P PORT.CUSTOM (signal) | HY2.0-4P: black GND, red 5V, yellow G32, white G33 | source p.7, PinMap | |
| G33 | HY2.0-4P PORT.CUSTOM (signal) | source p.7, PinMap | ||
| HY2.0-4P | Port pins: black GND, red 5V, yellow G32, white G33 | Also a 5 V pin; ESP32 logic is 3.3 V so signal pins are 3.3 V only | source p.7, PinMap (HY2.0-4P) |
Build with it
Project ideas for the M5Stack CoreInk. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- A desk note board that shows a short text message on the screen of an M5Stack CoreInk: The 200 x 200 e-ink screen keeps the image with no power, and the full refresh takes about 2 s; update it from a phone over Wi-Fi. Keep refreshes to about one every 15 s or slower as M5Stack advises.
- An e-ink to-do list that I edit with the dial switch on an M5Stack CoreInk: The dial switch (up G37, press G38, down G39) and user button G5 give four inputs, enough to scroll and tick items on the e-ink screen.
- An e-ink countdown timer that wakes on schedule with an M5Stack CoreInk: The BM8563 RTC on G21 and G22 wakes the board for a refresh and the buzzer on G2 signals the end, so the battery lasts between updates.
- A weekly habit tracker on an M5Stack CoreInk using the dial switch and e-ink screen: The e-ink screen holds the grid without power, the dial marks a day done, and the RTC keeps the date between wake-ups.
Common mistakes
- Refreshing the E-Ink screen at a high frequency for a long time: the product note says to avoid long-term high-frequency refresh and quotes the recommended refresh interval as "(15s / time)". (source: link, Notes, p.2)
- Leaving the screen in strong ultraviolet light for long periods: the note says this can cause irreversible damage to the E-Ink screen. (source: link, Notes, p.2)
Not covered by the official source
- The PinMap voltage column is not stated in the product document; GPIO voltage fields are not given.
- The GDEY0154D67 display datasheet and the ESP32-PICO-D4 datasheet are not given on this page; the CoreInk page lists them as links.
- The HY2.0-4P port exposes G32, G33 and 5 V; whether 5 V is output or input is not stated in the product document, so no external parts are used in the ideas.
- Pin voltages from the schematic are not included; GPIO voltage fields are not given.