README
¶
About The Project
go-st7066u is a minimalistic Go driver for 1 or 2 rows, 32 or 40 columns, 5x8 or 5x11 dots LCD displays using the ST7066 chip.
I wrote this because
- I wanted a driver for Go
- I noticed small differences (mostly regarding timing) in the available drivers for the HD4470 chip
So I reconned I'd write my own :)
Note! I have not been able to test this on any other display than the one I'm using, and in any other configuration than the one I've used to hook it up to my Raspberry Pi, so I make no claim that it will work in your case. I have my ST7066 chip based 1602 LCD display hooked up to the Pi in the 4-bit configuration (using 4 only data wires) and not using the R/W (i.e. keeping it low/to gnd).
...OK, to be honest; I haven't tested it much at all...
A big shout out and thanks to the guys and gals behind:
on which this is built.
Installation
go get github.com/hossner/go-st7066u
Usage
package main
import (
"time"
"log"
"github.com/hossner/go-st7066u"
)
func main() {
lcd, err := st7066u.New(
2, // nr of rows
16, // nr of columns/characters
st7066u.DOTS5x8, // font is 5x8 dots
st7066u.BITMODE4, // using 4-bit mode
7, // RS pin
8, // E pin
15, // L (or LED) pin
18, // D4 pin
23, // D5 pin
24, // D6 pin
25 // D7 pin
)
if err != nil {
log.Fatalln(err)
}
// Turn the backlight on
lcd.LedOn(true)
// Cursor starts by default positioned at row 0, col 0
// Print something..
lcd.Print("Hello")
// Move cursor to second row, at first column/character position
lcd.SetCursor(1, 0)
// Print...
lcd.Print("World")
time.Sleep(time.Second * 5)
lcd.LedOn(false)
lcd.Close()
}
API
Struct Device is the basic representation of the LCD display. Retrieve a new instance using the New function. Then the following functions can be used:
Clear()
Clears the display and positions the cursor at row 0, column 0.
Close()
Closes the gpio. Call this last.
CursorBlink(on bool)
Makes the cursor blink.
CursorOn(on bool)
Shows/hides the cursor. Default is hidden.
Home()
Returns the cursor at row 0, column 0.
LedON(on bool)
Turns on/off the backlight.
MoveLeft(steps uint8)
Moves the position of the cursor the provided nr of steps to the left.
New(nrOfRows, nrOfCols uint8, charSym uint8, mode uint8, pinRS, pinE, pinL rpio.Pin, pins ...rpio.Pin) (*Device, error)
New returns a pointer to a new device struct. The parameters are:
- Number of rows and columns on the display. 1 and 2 rows, and up to 40 columns are supported.
- The symmetry of the characters on the display. 5 x 8 (DOTS5x8) and 5 x 11 (DOTS5x11) are supported. Note that only 5 x 8 dot characters are supported on displays with two rows.
- If the display is connected using 4 (BITMODE4) or 8 (BITMODE8) data wires.
- The pins for the RS, E and L (or A/anode) wires. Note that this driver does not support usage of the R/W pin, this needs to be held low (to ground).
- The 4 or 8 pins for datatransfer. Start with the lowest D-pin (on the display), i.e. D0 (in BITMODE8) or D4 (in BITMODE4).
The function returns nil if an error is returned.
Print(text string)
Prints the provided string. Note the character set supported by the display (see datasheet at page 14).
PrintAt(row, col uint8, text string)
Prints the provided string at the provided postion.
PrintByte(byte)
Prints the provided byte.
PrintRune(rune)
Prints the provided rune.
SetCursor(row, col uint8)
Moves the cursor to the provied location.
TurnOn(on bool)
Turns the display on/off. Note that this doesn't close the gpio's - use Close() for that.
Issues / TBA
- Use of the R/W pin is not implemented (which would probably make it both faster and more stable), so the R/W pin must be held low (to gnd)
- The ST7066 chip has support for user-provided characters, but that functionality is not implemented
- More tests and testing is needed!
- This driver implements the ROM code 0A variant of the ST7066U chip, but there are character mappings missing (as I don't know what they represent...)
License
Distributed under the MIT License. See LICENSE for more information.
Documentation
¶
Index ¶
- Constants
- type Device
- func (l *Device) Clear()
- func (l *Device) Close()
- func (l *Device) CursorBlink(on bool)
- func (l *Device) CursorOn(on bool)
- func (l *Device) Home()
- func (l *Device) LedOn(on bool)
- func (l *Device) MoveLeft(steps uint8)
- func (l *Device) Print(text string)
- func (l *Device) PrintAt(row, col uint8, text string)
- func (l *Device) PrintByte(ch byte)
- func (l *Device) PrintRune(ch rune)
- func (l *Device) SetCursor(row, col uint8)
- func (l *Device) TurnOn(on bool)
Constants ¶
const ( BITMODE4 uint8 = iota BITMODE8 )
BITMODE4 and BITMODE8; used to denote if the LCD display is used in 4 or 8 bit mode respectively
const ( DOTS5x8 uint8 = iota DOTS5x11 )
DOTS5x8 and DOTS5x11; used to specifify the dot matrix used by the LCD display
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Device ¶
type Device struct {
// contains filtered or unexported fields
}
Device is the basic struct representing the LCD display. Use func New to get a new struct
func New ¶
func New(nrOfRows, nrOfCols uint8, charSym uint8, mode uint8, pinRS, pinE, pinL rpio.Pin, pins ...rpio.Pin) (*Device, error)
New returns a Device struct used as a handler for the LCD display. Arguments are
nrOfRows: (uint8) 1 or 2 rows LCD displayes are supported nrOfCols: (uint8) Nr of columns in the display. 16 and 20 are common values charSym: Symmetry of the characters on the LCD display. DOTS5x8 or DOTS5x11 are supported mode: In which "mode" the display is connected (w/ 4 or 8 data wires). BITMODE4 and BITMODE8 are supported pinRS: GPIO pin used for the RS (reset) pin on the LCD display pinE: GPIO pin used for the E (enable) pin on the LCD display pinL: GPIO pin used for the L (LED) pin on the LCD display pins: GPIO pins used for data, can be either 4 or 8 pins. Start with the lowest numbered pin on the LCD display (D0 or D4, depending on "mode" used)
func (*Device) CursorBlink ¶
CursorBlink sets the cursor to blink/not blink
func (*Device) Home ¶
func (l *Device) Home()
Home moves the cursor to the home position, i.e. row 0, col 0
func (*Device) Print ¶
Print prints the provided text on the LCD display at the current position of the caret
Source Files