Week12：Output devices

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Preparation: Test the lcd module in arduino

• Hardware testing：
  • I picked Hitachi HD44780U 1602 LCD module,Variable Resistor,, and . Trying to display "Hello world" message to testify the module.
  • Following this tutorial http://coopermaa2nd.blogspot.tw/2010/12/arduino-lab9-2x16-lcd-world.html
  • Connect the wire：
    • Arduino pin12 <-> LCD pin RS
    • Arduino pin11 <-> LCD pin E
    • Arduino pin5 <-> LCD pin DB4
    • Arduino pin4 <-> LCD pin DB5
    • Arduino pin3 <-> LCD pin DB6
    • Arduino pin2 <-> LCD pin DB7
    • Arduino 5V <-> LCD VCC
    • Arduino GND <-> LCD pin
    • Arduino GND <-> LCD R/W
    • Arduino GND <-> LCD VSS
    • Potentiometer left pin <-> Arduino GND
    • Potentiometer middle pin <-> LCD V0
    • Potentiometer right pin <-> Arduino 5V
• Use the following sample code to drive the LCD display.

/*
 This example code is in the public domain.
 http://www.arduino.cc/en/Tutorial/LiquidCrystal
*/

#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

void setup() {
  lcd.begin(16, 2);
  lcd.print("hello, world!");
}
void loop() {
  lcd.setCursor(0, 1);
  lcd.print(millis()/1000);
}

Using Attiny44 to drive LCD with Hello.LCD.44.c

• connect the wire, reffer to output tutorial.
  • Atiny44 pin10 <-> LCD DB4
  • Atiny44 pin11 <-> LCD DB5
  • Atiny44 pin12 <-> LCD DB6
  • Atiny44 pin13 <-> LCD DB7
• use the hello.lcd44.c sample code Download from fabacademy website to trigger LCD.

• The layout file is here:
  .sch file
  .brd file

Use I2C protocol to control the LCD

• In order to complete the final project, I find a I2C module that only use 2 pins to connect to the arduino board. I decide to use this module to control the LCD pannel with Analog pin4(SDA), Analog pin5(SCL), VCC and GND.
• use LiquidCrystal_I2C sample codedownload from wikispaces
  

the sample code as fallows:

#include <Wire.h>

#include <LiquidCrystal_I2C.h>
    
LiquidCrystal_I2C lcd(0x27,16,2);

void setup(){
lcd.init();
lcd.backlight();
lcdprint("Hello World");
}

void loop(){
}

• What I learn:
  • understand the character display method.
  • understand the lcd module operation method.
  • control the lcd message display and clear.