3.7 inch 4-colour e-paper (416x240): specs and pinout
A 3.7 inch four-colour e-paper panel (red, yellow, black, white) with 416 x 240 pixels and an SPI interface, made by Waveshare as the '3.7inch e-Paper HAT+ (G)'. It comes as a raw panel or with a driver board that plugs onto the Raspberry Pi 40-pin header or connects by a 9-pin cable.
Specs
| Spec | Value | Source |
|---|---|---|
| Display size and resolution | 3.7 inch; 416 x 240 pixels; dot pitch 0.196 mm x 0.196 mm; display area 81.54 mm x 47.04 mm | source Overview > Parameters |
| Display colours | Red, yellow, black, white (2 bits per pixel in the data format) | source Overview > Parameters; Operating Principle |
| Operating voltage | Raw panel: 3.3 V. Driver board: 3.3 V or 5 V, with the I/O level equal to the supply voltage | source Overview > Parameters; notes under 'Operating Principle' |
| Interface | SPI, mode 0 (CPOL 0, CPHA 0); control lines CS, SCL, D/C, SDA, plus RST and BUSY | source Communication Method |
| Refresh time | Fast refresh 12 s; full refresh 20 s (test data from Waveshare, flicker during a full refresh is normal) | source Overview > Parameters |
| Refresh power | Less than 30 mW (typical), test data for one refresh | source Overview > Parameters |
| Operating temperature | 0 to 40 C; storage -25 to 70 C | source Overview > Parameters |
| Outline | Panel 92.99 mm x 53.00 mm x 1.00 mm; driver board 96.00 mm x 57.00 mm | source Overview > Parameters |
| Refresh limits | Refresh at most every 180 s and at least once every 24 hours; put the panel to sleep or cut power when not refreshing | source Notes under 'Operating Principle' |
Power
| Value | Source | |
|---|---|---|
| Supply | Raw panel 3.3 V; driver board 3.3 V or 5 V (I/O level equal to supply) | source Overview > Parameters (only refresh power, under 30 mW typical, is given; no current figure) |
Pinout
Pin names and Raspberry Pi wiring are from Waveshare's manual for the 3.7inch e-Paper HAT+ (G) driver board (9-pin cable connection). The raw panel has its own flat-cable connector that this manual does not draw.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| VCC | Power supply | 3.3 V | Wired to Raspberry Pi 3.3 V in the manual's table | source Hardware Connection: Raspberry Pi connection pin correspondence (9-pin cable) |
| GND | Ground | Wired to Raspberry Pi GND | source Hardware Connection: Raspberry Pi connection pin correspondence (9-pin cable) | |
| DIN | SPI data in (SDA) | Raspberry Pi MOSI, physical pin 19 | source Hardware Connection: Raspberry Pi connection pin correspondence (9-pin cable) | |
| CLK | SPI clock (SCL) | Raspberry Pi SCLK, physical pin 23 | source Hardware Connection: Raspberry Pi connection pin correspondence (9-pin cable) | |
| CS | Chip select, active low | Raspberry Pi CE0, physical pin 24 | source Hardware Connection: Raspberry Pi connection pin correspondence (9-pin cable) | |
| DC | Data/command select: low = command, high = data | Raspberry Pi BCM 25, physical pin 22 | source Hardware Connection: Raspberry Pi connection pin correspondence (9-pin cable) | |
| RST | Reset | Raspberry Pi BCM 17, physical pin 11 | source Hardware Connection: Raspberry Pi connection pin correspondence (9-pin cable) | |
| BUSY | Busy status | Raspberry Pi BCM 24, physical pin 18 | source Hardware Connection: Raspberry Pi connection pin correspondence (9-pin cable) | |
| PWR | Power control | Raspberry Pi BCM 18, physical pin 12 | source Hardware Connection: Raspberry Pi connection pin correspondence (9-pin cable) |
Build with it
Project ideas for the 3.7 inch 4-colour e-paper (416x240). Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Pi status board: The driver board plugs onto the 40-pin header and uses 3.3 V logic. Refresh at most every few minutes (the manual allows one refresh per 180 s) and sleep the panel in between.
- Pi Zero daily calendar card: The Zero W has a 3.3 V header and Wi-Fi, so it can fetch the data and redraw once an hour. Red and yellow work for highlights. Keep the refresh interval above 180 s as the manual advises.
- ESP32 room climate card: Use the 9-pin cable connection with the ESP32's 3.3 V pin and SPI pins of your choice. Update the card every 30 minutes and sleep the panel between updates; the 12 s to 20 s refresh is fine for slow-changing readings. The manual's 9-pin table is for a Raspberry Pi; choose the SPI pins on the ESP32 or Pico yourself.
- Pico meeting-room sign: The Pico is a 3.3 V board, matching the raw panel's 3.3 V working voltage. Redraw when the status changes but not more often than every 180 s as the manual advises: hold a change that arrives sooner and redraw later. The manual's 9-pin table is for a Raspberry Pi; choose the SPI pins on the ESP32 or Pico yourself.
Common mistakes
- Leaving the panel powered or in its active state after a refresh: Waveshare says a long time on high voltage damages the panel permanently, so send the sleep command or cut power after each refresh (source)_Manual, notes under Operating Principle)
- Refreshing too often: the manual recommends at least 180 s between refreshes and a refresh at least every 24 hours, and a 12 s to 20 s refresh means this panel suits status pages, not animation (source)_Manual, Parameters and notes)
- Driving the raw 3.3 V panel from 5 V logic: the manual says the working voltage is 3.3 V and recommends level conversion for a 5 V circuit; on the driver board the I/O level must equal the supply voltage (source)_Manual, Parameters and notes)
Not covered by the official source
- The display controller chip is not named in the manual, so no controller datasheet is cited.
- The manual covers both the raw panel and the driver-board version; the pin table and the 3.3 V / 5 V rule belong to the driver board.
- No current figure is given other than the refresh power (under 30 mW typical).