This library contains a driver for E-Paper Modules from Waveshare (which are basically the same as the Dalian Good Display ones).

It uses the embedded graphics library for the optional graphics support.

A 2018-edition compatible version (Rust 1.31+) is needed.

Other similiar libraries with support for much more displays are u8g2 and GxEPD for arduino.

Examples

There are multiple examples in the examples folder. Use cargo run --example example_name to try them.

// Setup the epd
let mut epd = EPD4in2::new(&mut spi, cs, busy, dc, rst, &mut delay)?;

// Setup the graphics
let mut display = Display4in2::default();

// Draw some text
display.draw(
    let _ = Text::new("Hello Rust!", Point::new(x, y))
        .into_styled(text_style!(
            font = Font12x16,
            text_color = Black,
            background_color = White
        ))
        .draw(display);
);

// Transfer the frame data to the epd and display it
epd.update_and_display_frame(&mut spi, &display.buffer())?;

(Supported) Devices

Device (with Link)	Colors	Flexible Display	Partial Refresh	Supported	Tested
7.5 Inch B/W V2 (A) [1]	Black, White	✕	✕	✔	✔
7.5 Inch B/W (A)	Black, White	✕	✕	✔	✔
4.2 Inch B/W (A)	Black, White	✕	Not officially [2]	✔	✔
1.54 Inch B/W (A)	Black, White	✕	✔	✔	✔
2.13 Inch B/W (A) V2	Black, White	✕	✔	✔	✔
2.9 Inch B/W (A)	Black, White	✕	✔	✔	✔
1.54 Inch B/W/R (B)	Black, White, Red	✕	✕	✔	✔
2.9 Inch B/W/R (B/C)	Black, White, Red	✕	✕	✔	✔

[1]: 7.5 Inch B/W V2 (A)

Since November 2019 Waveshare sells their updated version of these displays. They should have a "V2" marking sticker on the backside of the panel.

Use epd7in5_v2 instead of epd7in5, because the protocol changed.

[2]: 4.2 Inch E-Ink Black/White - Partial Refresh

Out of the Box the original driver from Waveshare only supports full updates.

That means: Be careful with the quick refresh updates:
It's possible with this driver but might lead to ghosting / burn-in effects therefore it's hidden behind a feature.

Interface

Interface	Description
VCC	3.3V
GND	GND
DIN	SPI MOSI
CLK	SPI SCK
CS	SPI chip select (Low active)
DC	Data/Command control pin (High for data, and low for command)
RST	External reset pin (Low for reset)
BUSY	Busy state output pin (Low for busy)

Display Configs

There are two types of Display Configurations used in Wavedshare EPDs, which also needs to be set on the "new" E-Paper Driver HAT. They are also called A and B, but you shouldn't get confused and mix it with the Type A,B,C and D of the various Displays, which just describe different types (colored variants) or new versions. In the Display Config the seperation is most likely due to included fast partial refresh of the displays. In a Tabular form:

Type A	Tybe B
1.54in (A)	1.54in (B)
2.13in (A)	1.54in (C)
2.13in (D)	2.13in (B)
2.9in (A)	2.13in (C)
	2.7in (A)
	2.7in (B)
	2.9in (B)
	2.9in (C)
	4.2in (A)
	4.2in (B)
	4.2in (C)
	7.5in (A)
	7.5in (B)
	7.5in (C)