LCD20*4 i2c c qt

วันนี้ได้มีโอกาศใช้งาน LCD20*4 กับภาษา C ก็เลยอยากกระจายความสะดวกให้คนที่ทำทีหลัง โดยการเอา source code มาวางให้ครับ

โดยผมใช้ ภาษา C Qt Creator cross-compile บน linux ubuntu16.04 กับ rpi-3b และต่อ LCD ด้วย I2C

//============== mylcd.h =================//
 #ifndef MYLCD_H
#define MYLCD_H

#define I2C_ADDR_LCD1    0x26    // LCD I2C Address

#define LCD_CHR     1       // Mode sending data
#define LCD_CMD     0       // Mode sending command

#define LINE1       0x80    // 1st line
#define LINE2       0xc0    // 2nd line
#define LINE3       0x94    // 1st line
#define LINE4       0xd4    // 2nd line

#define LCD_BACKLIGHT   0x08    // on
//#define LCD_BACKLIGHT   0x00    // off

#define ENABLE          0b00000100  // enable bit

void typeInt(int i);
void typeFloat(float myFloat);
void lcdLoc(int line);          // move cursor
void ClrLcd(void);              // clr LCD return home
void typeln(const char *s);
void typeChar(char val);

void lcd_init(void);
void lcd_byte(int bits, int mode);
void lcd_toggle_enable(int bits);

int fd;

#endif // MYLCD_H




//============== main.c =================//
#include <QCoreApplication>
#include <wiringPi.h>
#include <wiringPiI2C.h>
#include <stdlib.h>
#include <stdio.h>
#include <mylcd.h>
#include <QDebug>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    if(wiringPiSetup()==-1){
        qDebug() << "can't open wiring pi";
    }
    else
    {
        qDebug() << "open wiring pi!!!";
    }

    fd = wiringPiI2CSetup(I2C_ADDR_LCD1);

    lcd_init();

    char array1[] = "Hello world!";

    while(1)
    {
        ClrLcd();

        lcdLoc(LINE1);
        typeln("Using wiringPi");
        lcdLoc(LINE2);
        typeln("Niran editor");
        lcdLoc(LINE3);
        typeln("I2c programmed");
        lcdLoc(LINE4);
        typeln("In C not python");
        delay(2000);

        ClrLcd();
        lcdLoc(LINE1);
        typeln(array1);

        delay(2000);
        ClrLcd();
        typeln("Int  ");
        int value = 20125;
        typeInt(value);

        delay(2000);
        lcdLoc(LINE2);
        typeln("Float  ");
        float Floatvalue = 10045.25989;
        typeFloat(Floatvalue);
    }

    return a.exec();
}

void typeln(const char *s){
    while(*s){
        lcd_byte(*(s++), LCD_CHR);
    }
}

// float to string
void typeFloat(float myFloat){
    char buffer[20];
    sprintf(buffer,"%4.2f", myFloat);
    typeln(buffer);
}

// int to string
void typeInt(int i){
    char array1[20];
    sprintf(array1,"%d", i);
    typeln(array1);
}

void ClrLcd(void){
    lcd_byte(0x01,LCD_CMD);
    lcd_byte(0x02,LCD_CMD);
}

void lcdLoc(int line){
    lcd_byte(line, LCD_CMD);
}

void typeChar(char val){
    lcd_byte(val,LCD_CHR);
}

void lcd_byte(int bits, int mode){
    int bits_high;
    int bits_low;

    bits_high   = mode | (bits & 0xF0) | LCD_BACKLIGHT;
    bits_low    = mode | ((bits<<4) & 0xF0) | LCD_BACKLIGHT;

    wiringPiI2CReadReg8(fd,bits_high);
    lcd_toggle_enable(bits_high);

    wiringPiI2CReadReg8(fd,bits_low);
    lcd_toggle_enable(bits_low);
}

void lcd_toggle_enable(int bits){
    delay(10);
    wiringPiI2CReadReg8(fd,(bits|ENABLE));
    delay(10);
    wiringPiI2CReadReg8(fd,(bits|~ENABLE));
    delay(10);
}

void lcd_init(){
    lcd_byte(0x33,LCD_CMD);
    lcd_byte(0x32,LCD_CMD);
    lcd_byte(0x06,LCD_CMD);
    lcd_byte(0x0C,LCD_CMD);
    lcd_byte(0x28,LCD_CMD);
    lcd_byte(0x01,LCD_CMD);
    delay(500);
}