pertelian

README

Pertelian

Talking to Pertelian character LCD displays in Go

Note that only the Pertelian X2040 is supported at the moment. I don't know if there are any other Pertelian displays in existance. This is the one I had laying around in a drawer, so this is the one I wanted to play with.

Underdocumented

This is just something I threw together for my own use. It's only public becasue I'm also playing around with putting my Go code on GitHub.

Originally part of a different project, but I figured I might as well toss it out there for general use.

Enjoy to the extent possible.

Example

package main

import (
	"log"
	"time"
	"github.com/DemmyDemon/pertelian"
	"github.com/google/gousb"
)

func main() {

    // First we need to get a hold of a USB context to work with.
    // Explaining how to get gousb up and running with the Pertelian X2040 is out of scope here.
	ctx := gousb.NewContext()
    // Suffice to say, read the gousb documentation.
    // Windows? Strongly consider https://zadig.akeo.ie/

    // Releasing the USB context after use is very important, or so I've heard.
	defer ctx.Close()

    // Once we have a USB context, it all gets a lot simpler!
    // Instantiate a display object:
	pert, err := pertelian.NewX2040(ctx)

    // Errors can be stuff like "Device not found" (if you forgot to plug it in)
    // or "Unsupported" (if you have the wrong driver)
	if err != nil {
		log.Fatal(err)
	}

    // You should always close USB devices. If not, the USB gods will eat your cookies!
	defer pert.Close()
    // Note that this only closes the connection to the display, it does not turn it off.
    // It doesn't even blank it or turn off the light. It leaves it in whatever state it's in.

    // Turning the display on is a good idea if you want to put information on it.
	err = pert.On()
	if err != nil {
		log.Fatal(err)
	}

    // Splash screen. Very fancy.
	pert.Splash()

    // Sleeep for a while to show off the very fancy splash screen.
	time.Sleep(5 * time.Second)

    // Clear out the very fancy splash screen.
	pert.Clear()

    // Print some text roughly centered on the second line (first line is 0)
    pert.Centered(1, "Some Text")

    // Print more text on the third line, 0 characters offset from the left edge.
    pert.PrintAt(2, 0, "More Text")

    // Sleep again, of nobody will see the text.
	time.Sleep(5 * time.Second)

    // Shut down the display, because electricity is very expensive right now.
	err = pert.Off()
	if err != nil {
		log.Fatal(err)
	}
}

Documentation

Index

• Variables
• type PertelianX2040
  • func NewX2040(ctx *gousb.Context) (PertelianX2040, error)
  • func (pert *PertelianX2040) Blank(line uint8) error
  • func (pert *PertelianX2040) Centered(line uint8, text string) error
  • func (pert *PertelianX2040) Clear() error
  • func (pert *PertelianX2040) Close() error
  • func (pert *PertelianX2040) GetCharacters(slots ...uint8) string
  • func (pert *PertelianX2040) Light(state bool) error
  • func (pert *PertelianX2040) Off() error
  • func (pert *PertelianX2040) On() error
  • func (pert *PertelianX2040) Print(text string) error
  • func (pert *PertelianX2040) PrintAt(line uint8, char uint8, textString string) error
  • func (pert *PertelianX2040) SetCharacter(position uint8, char PertelianX2040Character) error
  • func (pert *PertelianX2040) SetLineDrawingCharacters()
  • func (pert *PertelianX2040) Splash()
  • func (pert *PertelianX2040) Write(data []byte) (int, error)
  • func (pert *PertelianX2040) WriteGibberish(data []byte) (int, error)
• type PertelianX2040Character
  • func NewX2040Char(lines ...string) (PertelianX2040Character, error)

Variables

var ErrX2040CharWant8Lines = errors.New("characters must be made up of exactly 8 lines")

var ErrX2040CharWidth5 = errors.New("character lines must be exactly 5 runes long")

var ErrX2040DeviceNotFound = errors.New("x2040 device not found")

var ErrX2040InvalidCharacterPosition = errors.New("invalid character position")

var ErrX2040OutOfRange = errors.New("target out of display range")

var ErrX2040UnknownWriteError = errors.New("unknown error writing to device")

Types

type PertelianX2040

type PertelianX2040 struct {
	// contains filtered or unexported fields
}

func NewX2040

func NewX2040(ctx *gousb.Context) (PertelianX2040, error)

NewX2040 instantiates a new PertelianX2040 for you to play with.

func (*PertelianX2040) Blank

func (pert *PertelianX2040) Blank(line uint8) error

Blank overwrites the given line with all spaces, effectively blanking it.

func (*PertelianX2040) Centered

func (pert *PertelianX2040) Centered(line uint8, text string) error

Centered attempts to send the given string so it's centered on the given line.

func (*PertelianX2040) Clear

func (pert *PertelianX2040) Clear() error

Clear removes all data visible on the display.

func (*PertelianX2040) Close

func (pert *PertelianX2040) Close() error

Close closes down the interface and closes the device. **DOES NOT** clear the display, turn off the light, or any of that.

func (*PertelianX2040) GetCharacters

func (pert *PertelianX2040) GetCharacters(slots ...uint8) string

GetCharacters returns a string built with the characters previously stored with SetCharacter.

func (*PertelianX2040) Light

func (pert *PertelianX2040) Light(state bool) error

Light sets the display light to the requested state.

func (*PertelianX2040) Off

func (pert *PertelianX2040) Off() error

Off turns off the light, and then the display.

func (*PertelianX2040) On

func (pert *PertelianX2040) On() error

On turns on the display, initializes it, clears any data already on there and turns the light on.

func (*PertelianX2040) Print

func (pert *PertelianX2040) Print(text string) error

Print sends a string entry to wherever the cursor happens to be.

func (*PertelianX2040) PrintAt

func (pert *PertelianX2040) PrintAt(line uint8, char uint8, textString string) error

PrintAt sends a string entry to the given line and character.

func (*PertelianX2040) SetCharacter

func (pert *PertelianX2040) SetCharacter(position uint8, char PertelianX2040Character) error

SetCharacter stores the given character in the display for later display. You get 7 slots, 0-6.

func (*PertelianX2040) SetLineDrawingCharacters

func (pert *PertelianX2040) SetLineDrawingCharacters()

SetLineDrawingCharacters stores a set of line drawing characters in the display.

func (*PertelianX2040) Splash

func (pert *PertelianX2040) Splash()

Splash does some line drawing and text to look fancy.

func (*PertelianX2040) Write

func (pert *PertelianX2040) Write(data []byte) (int, error)

Write writes directly to the device, pausing slightly after the first two characters. Note that this is done in one transmission per byte to minimize the chance of corruption.

func (*PertelianX2040) WriteGibberish

func (pert *PertelianX2040) WriteGibberish(data []byte) (int, error)

WriteGibberish writes directly to the device with no waiting for command processing, which *often* leads to corruption.

type PertelianX2040Character

type PertelianX2040Character struct {
	Lines [charSize]byte
}

func NewX2040Char

func NewX2040Char(lines ...string) (PertelianX2040Character, error)

NewX2040Char assists in creating a properly formatted custom character for the display.