LCD displays

• LiquidCrystal: official library included with the Arduino software (w/ 4- and 8-bit modes)
• Suggested Character based LCD API by dwentz
• The Arduino controls Serial LCD's over a simple four-wire connection, by djmatic.
• About Printing Number
• SparkFun serial LCD
  • Library for Sparkfun SerLCD
  • Another Library for Sparkfun SerLCD
  • Refactored Library for Sparkfun SerLCD
  • Writing Japanese characters to a Sparkfun SerLCD
• ioBridge Serial LCD
• Optrex IM050240 Serial LCD Driver (PCB marked with PWB50240-CEM). These are super cheap 4 digit displays, with no decimal points, and the words "CLEAR" and/or "SECURE". They must have been made for a security alarm. These are not smart, and must be continually refreshed (supplied software driver does this). They can be purchased as surplus for as little as $1.95. This software requires the use of library MsTimer2.
• display values on LCD screen - Translating analogRead(values) into ASCII code to display the value on a LCD screen.
• Philips PCD8544 (Nokia 3310) driver - Simple example of interfacing with the Nokia 3310 LCD.
• Parallax™ Serial LCD's - Library for controlling Parallax™ 3-wire serial LCD's

• Using 4-bit mode with Hitachi LCD controllers. There are now various code examples for how to talk to an HD44780-compatible LCD in 4-bit mode (in order to save arduino pins):
  • LiquidCrystal: official library included with the Arduino software (w/ 4- and 8-bit modes)
  • neillzero's 4-bit LCD library.
  • glasspusher's 4-bit forum post with code
  • massimo's 4-bit forum post with code
  • tomek added a schematic, picture, Commands for Character Modules and another code example
  • nuelectronics' LCD shield with joystick-style keypad - schematic and examples
  • LCD Smartie on Arduino - Communicate and show your PC status, email status, RSS feed and control your PC application on Arduino & LCD shield -- project link
  • 4-bit library example with schematic, photo and code. SK Pang.
  • API 1.0 compatible LiquidCrystal_I2C library for using PCF8574 I2C expander to control Parallel HD44780 displays
  • Another simple but functional library allows an Arduino board to control LCDs - Project Link

• Using Arduino via shiftregisters to connect to LCDs (in order to save even more output pins)
  • tomek's 4Bits documentation to make a 3 pin interface for LCDs
  • raron and mircho's arduinoshiftreglcd library, using a 2-wire or 3-wire connection in 4-bit mode.

• Using i2C to connect LCDs to Arduino
  • Complete API and library for using i2c based character displays.
  • Using I2C Port expander and LCDs (2 wire interface to LCD)

• Connecting LCDs using 1 pin, SoftwareSerial, and simple controller
  • Use an external serial interface Put a small PCB ($14 kit/more assembled) between your Arduino and any HD44780 compatible LCD, and you free pins and memory in the Arduino for things which are more fun than the details of driving the LCD. SoftwareSerial is one of the standard libraries.(Anderson/ ModernDevice/ Wulfden LCD117)

• Graphics LCD
  • KS0108 library
  • 12864 library
  • Philips PCF8833 library (Nokia 6100 Screen)
  • Epson S1D15G10 library (including Sparkfun's Nokia 6100 Knock-off color LCD)
  • T6963 Library
  • Dogm128 Library (ST7565R)

• Links
  • LCD chapter from free PIC microcontrollers book has some good explanation.
  • Ian Harries' "Initialisation of the HD44780"
  • Peter Ouwehand's "How to control a HD44780-based Character-LCD"
  • HD44780 datasheet
  • Dincer's JavaScript LCD Simulator or download offline version Download

Troubleshooting

• LCD display is too dark or too pale. All LCDs have a contrast setting, whether it is available to you for adjustment or not. Many have backlights. The latter parts of the guide to using an external serial controller address these issues in general terms, mostly independently of controller issues.

Printing Numbers

The itoa() stdlib C library function can be used to convert a number into a string, in a variety of bases (e.g. decimal, binary). The buffer must be large enough to hold the largest number, plus sign and terminating null: e.g. 32 bit base-10: "-2147483648\0" = 12 characters.

The stdlib itoa() library routine adds around 600 bytes, the roll-your-own K&R implementation, which includes string.h, adds around 670 bytes. Using snprintf() from stdio.h adds just over 2200 bytes.

e.g.

char buf[12]; // "-2147483648\0"
lcd.printIn(itoa(random(1024)-512, buf, 10));

Page maintenance:

• would an admin please
  • delete the attachment "LCD4BitLibrary", but KEEP LCD4BitLibrary.zip
  • delete the page Code.LCD4Bit