3 Wires LCD 74HC595

Nota: Ficamos assim com o Output do SR Q7 disponível, podemos usar o mesmo para controlar o backlight do LCD ou qualquer outro dispositivo (usando um transístor caso se exceda a corrente máxima permitida por cada pino do SR: 40mA).

Código de teste:

HelloWorld

include <Wire.h>

#include <LiquidCrystal_SR3W.h>

const int PIN_LCD_STROBE =  12; // Out: LCD IC4094 shift-register strobe LACH PIN  - STCP

const int PIN_LCD_DATA =  11;   // Out: LCD IC4094 shift-register data     DATA PIN  - DS

const int PIN_LCD_CLOCK =  10;  // Out: LCD IC4094 shift-register clock   CLOCK PIN - SHCP

LiquidCrystal_SR3W lcd(PIN_LCD_DATA, PIN_LCD_CLOCK, PIN_LCD_STROBE); // srdata / srclock / strobe

// Creat a set of new characters

byte armsUp[8] = {0b00100,0b01010,0b00100,0b10101,0b01110,0b00100,0b00100,0b01010};

byte armsDown[8] = {0b00100,0b01010,0b00100,0b00100,0b01110,0b10101,0b00100,0b01010};

const int    BACKLIGHT_PIN = 5;

void setup(){

  lcd.begin(16,2);               // initialize the lcd

  lcd.createChar (0, armsUp);    // load character to the LCD

  lcd.createChar (1, armsDown);    // load character to the LCD

  lcd.home ();                   // go home

  lcd.print("LiquidCrystal_SR");

}

void loop(){

  // Do a little animation

  for(int i = 0; i <= 15; i++) showHappyGuy(i);

  for(int i = 15; i >= 0; i--) showHappyGuy(i);

}

void showHappyGuy(int pos){

  lcd.setCursor ( pos, 1 ); // go to position

  lcd.print(char(random(0,2))); // show one of the two custom characters

  delay(550); // wait so it can be seen

  lcd.setCursor ( pos, 1 ); // go to position again

  lcd.print(" "); // delete character

}

Teste Completo:

//http://arduino-info.wikispaces.com/LCD-Blue-I2C

#include <Wire.h>

#include <LiquidCrystal_SR3W.h>

const int PIN_LCD_STROBE =  12; // Out: LCD IC4094 shift-register strobe LACH PIN  - STCP

const int PIN_LCD_DATA =  11; // Out: LCD IC4094 shift-register data     DATA PIN  - DS

const int PIN_LCD_CLOCK =  10; // Out: LCD IC4094 shift-register clock   CLOCK PIN - SHCP

// srdata / srclock / strobe / bl pin on SR / blpol (positive\negative)

LiquidCrystal_SR3W lcd(PIN_LCD_DATA, PIN_LCD_CLOCK, PIN_LCD_STROBE, 7, POSITIVE); // 7 e POSITIVE definem estão associados ao output Q7 

// Creat a set of new characters

byte heart[8] = {

  0b00000, 0b01010, 0b11111, 0b11111, 0b11111, 0b01110, 0b00100, 0b00000

};

byte smiley[8] = {

  0b00000, 0b00000, 0b01010, 0b00000, 0b00000, 0b10001, 0b01110, 0b00000

};

byte frownie[8] = {

  0b00000, 0b00000, 0b01010, 0b00000, 0b00000, 0b00000, 0b01110, 0b10001

};

byte armsDown[8] = {

  0b00100, 0b01010, 0b00100, 0b00100, 0b01110, 0b10101, 0b00100, 0b01010

};

byte armsUp[8] = {

  0b00100, 0b01010, 0b00100, 0b10101, 0b01110, 0b00100, 0b00100, 0b01010

};

void setup() {

  // put your setup code here, to run once:

  lcd.begin(16, 2);  // initialize the lcd for 16 chars 2 lines, turn on backlight

  // load characters to the LCD

  lcd.createChar(0, smiley);

  lcd.createChar(1, frownie);

  lcd.createChar(2, armsDown);

  lcd.createChar(3, armsUp);

  lcd.createChar(4, heart);

  lcd.clear();

  lcd.home ();    //go home

  lcd.setCursor (0, 0); //XY

  lcd.print(F("LiquidCrystalSR3"));

  lcd.setCursor (0, 1);

  lcd.print(F("World "));

  lcd.print(char(4));

  lcd.print(char(2));

  lcd.print(char(3));

  delay(2000);

  // ------- Quick 3 blinks of backlight  -------------

  for (int i = 0; i < 3; i++)

  {

    lcd.backlight();

    delay(450);

    lcd.noBacklight();

    delay(450);

  }

  lcd.backlight(); // finish with backlight on

}

void loop() {

lcd.clear();

  for (int i = 5; i <= 15; i++) {

    lcd.setCursor ( i, 1 );

    lcd.print(char(random(0, 2)));

    delay(100);

    lcd.setCursor ( i, 1 );

    lcd.print(F(" "));

  }

  for (int i = 15; i >= 5; i--) {

    lcd.setCursor ( i, 1 );

    lcd.print(char(random(0, 2)));

    delay(100);

    lcd.setCursor ( i, 1 );

    lcd.print(F(" "));

  }

   // Turn the display on/off

  lcd.setCursor ( 5, 1 );

  lcd.print(F("screen off"));

  delay(1000);

  lcd.noDisplay();

  delay(1000);

  lcd.display();

  lcd.clear();

  lcd.setCursor ( 5, 1 );

  lcd.print(F("CURSOR"));

  delay(1000);

  lcd.setCursor ( 5, 1 );

  lcd.cursor();

  delay(2000);

  lcd.noCursor();

  lcd.clear();

  lcd.setCursor ( 5, 1 );

  lcd.print(F("BLINK"));

  lcd.setCursor ( 5, 1 );

  lcd.blink();

  delay(2000);

  lcd.noBlink();

  lcd.clear();

  lcd.setCursor ( 5, 1 );

  lcd.print(F("SCROLL"));

  delay(1000);

  //SCROLL TEST

  for (uint8_t positionCounter = 0; positionCounter < 10; positionCounter++) {

    // scroll one position left:

    lcd.scrollDisplayLeft();

    // wait a bit:

    delay(50);

  }

  // scroll 16 positions (display length + string length) to the left

  // to move it back to center:

  for (uint8_t positionCounter = 0; positionCounter < 10; positionCounter++) {

    // scroll one position left:

    lcd.scrollDisplayLeft();

    // wait a bit:

    delay(50);

  }

  lcd.setCursor ( 0, 1 );

  lcd.print(F("               "));

}

Testando a saída Q7 (podemos colocar um LED ligado a este pino (com uma resistência de 220R ao negativo)):

//http://arduino-info.wikispaces.com/LCD-Blue-I2C

#include <Wire.h>

#include <LiquidCrystal_SR3W.h>

const int PIN_LCD_STROBE =  12; // Out: LCD IC4094 shift-register strobe LACH PIN  - STCP

const int PIN_LCD_DATA =  11; // Out: LCD IC4094 shift-register data     DATA PIN  - DS

const int PIN_LCD_CLOCK =  10; // Out: LCD IC4094 shift-register clock   CLOCK PIN - SHCP

// srdata / srclock / strobe / bl pin on SR / blpol (positive\negative)

LiquidCrystal_SR3W lcd(PIN_LCD_DATA, PIN_LCD_CLOCK, PIN_LCD_STROBE, 7, POSITIVE);

void setup() {

  // put your setup code here, to run once:

  lcd.begin(16,2);   // initialize the lcd for 16 chars 2 lines, turn on backlight

  lcd.clear();

  lcd.setCursor(0,0); //Start at character 0 on line 0

  lcd.print("LCD DISPLAY");

  lcd.setCursor(0,1);

  lcd.print("TEST");  

  // ------- Quick 3 blinks of backlight  -------------

  for(int i = 0; i< 3; i++)

  {

    lcd.backlight();

    delay(450);

    lcd.noBacklight();

    delay(450);

  }

  lcd.backlight(); // finish with backlight on  

}

void loop() {

  // put your main code here, to run repeatedly:

}

Vídeo final: