epaper

Overview

This is a Go library that exposes the interface of Waveshare's 4.3inch e-Paper UART Module.

Most of the interface follows the wiki page above, but some of it was derived by experimenting with the device.

Usage

Connecting

To connect the e-Paper module, you'll probably need a USB to TTL serial cable. These are cheap and can be found in many online stores that sell Arduino and Raspberry Pi accessories. Once you connect it to your PC, you need to find out which port it uses. On Linux, it'll likely be /dev/ttyUSB0. On Windows, use Device Manager to find out.

If you intend to use it on the Raspberry Pi, you can use the Pi's own serial interface. See here for more info - specifically, on how to prevent Linux from using the serial port. The serial port on a Raspberry Pi is either /dev/ttyAMA0 (prior to Raspberry Pi 3) or /dev/ttyS0 (Raspberry Pi 3).

Drawing things

Drawing on the device is achieved by first sending one or more commands which modify the "screen state" on the device itself and then calling the Update command which draws the current state.

The following commands are able to modify the "screen state":

• Manipulating a single pixel
  • FillPixel
  • ColorPixel
• Drawing shapes
  • DrawLine
  • ColorLine
  • DrawRect
  • DrawCircle
  • DrawTriangle
• Filling shapes
  • FillRect
  • FillCircle
  • FillTriangle
• Whole screen manipulation
  • Clear
  • FillScreen
• Miscellaneous
  • DisplayText
  • DisplayImage

Example

  ep, err := epaper.New("/dev/ttyUSB0")
  // handle error
  err = ep.DrawRect(100, 100, 200, 200)
  // handle error
  err = ep.Update()
  // handle error
  ep.Close()

For a more comprehensive example, see example_test.go.

Documentation

Please see the GoDoc documentation for documentation.

The Waveshare wiki page also provides useful information on what many of the commands do and how they are used.