MCU through PCF8574T module driver 1602/2004LCD

The microcontroller drives the 1602/2004 LCD through the PCF8574T module. Friends in need can take a look. //-----------------------------------------------------------------------------------------------------------------------------------------------------------------------

#include
#include "intrins.h"
#define uchar unsigned char
#define uint unsigned int 


//#define L1 0x80 // The first line write address
//#define L2 0xc0 // The second line write address
        
sbit SCL = P2^0;
sbit SDA = P2^1;


//char ADDR = 0x4E; // The address code of the PCF8574 T module
  char ADDR = 0x7e; // The address code of the PCF8574 AT module


//***************************** Delay y ms ***************************************************


void delay1(int y) // 
{
         ;
        while(y--)
        {
        unsigned char a,b,c;
        for(c=1;c>0;c--)
        for(b=142;b>0;b--)
        for(a=2;a>0;a--);
        }
}


//******************************** IIC serial port starts********************************************


void IIC_start(void)
{
        SDA=1;
        _nop_();
        SCL=1;
        _nop_();
        _nop_();
        _nop_();
        _nop_();
        _nop_();
        SDA=0;
        _nop_();
        _nop_ (
        );
        _nop_(); _nop_()
        ;
        SCL=0;
}




//********************************** IIC serial port writes 1 byte******************************************


void IIC_writeByte(char temp)
{
        char i;
        for(i=0;i<8;i++)
        {
                SDA=(bit)(temp & 0x80); // According to the regulations, the highest bit of 1602 data must be 1  
                temp <<=1;
                _nop_();
                _nop_();
                SCL=1;                 _nop_
                ();                 _nop_(); _nop_();                 _nop_();                 _nop_();                 SCL=0;         }         _nop_();          _nop_();         _nop_();         _nop_();         SDA=1;         _nop_();          _nop_();          _nop_();         _nop_();         SCL=1;          _nop_();         _nop_();         _nop_();         while(SDA);         _nop_();         SCL=0; }



























//******************************** 1602 write command********************************************


void LCD_write_command(char comm)
{
        char tmp;
        IIC_start(); // Serial port starts
        IIC_writeByte(ADDR); // Select the address of PCF 8574T first (it should be equivalent to the meaning of selection)
        
        tmp = comm & 0xF0; // and 0xf0 should mean taking the fourth bit
        tmp |= 0x0C; //Retain the upper 4 bits as the upper 4 bits of the instruction, and the lower 4 bits are RS = 0, RW = 0, EN = 1 IIC_writeByte  
        (tmp); //Send
        delay1(20) from the serial port;
        tmp &= 0xFB; //Make EN = 0
        IIC_writeByte(tmp); 
        
        tmp = (comm & 0x0F) << 4 ; //Send the lower 4 bits of the instruction to the high position for storage
        tmp |= 0x0C; //RS = 0, RW = 0, EN = 1
        IIC_writeByte(tmp);
        delay1(20);
        tmp &= 0xFB; // Make EN = 0
        IIC_writeByte(tmp);
        
}
//******************************** 1602 write data********************************************


void LCD_write_data(char data1)
{
        char tmp;
        IIC_start();
        IIC_writeByte(ADDR); // Select the address of PCF 8574T first (it should be equivalent to the meaning of selection)
        
        tmp = data1 & 0xF0;
        tmp |= 0x0D; //RS = 0, RW = 0, EN = 1
        IIC_writeByte(tmp);
        delay1(20);
        tmp &= 0xFB; //Make EN = 0
        IIC_writeByte(tmp); 
        
        tmp = (data1 & 0x0F) << 4 ;
        tmp |= 0x0D; //RS = 0, RW = 0, EN = 1
        IIC_writeByte(tmp);
        delay1(20);
        tmp &= 0xFB ; // Make EN = 0
        IIC_writeByte(tmp);
}


//******************************** 1602 Initialization********************************************


void Init_Lcd(void)
{
        LCD_write_command(0x33); //Convert 8-bit bus to 4-bit bus
        delay1(50);
        LCD_write_command(0x32); //
        delay1(50); 
        LCD_write_command(0x28); // 4-bit data line, display 2 lines, 5*7 dot matrix characters! If it is 0x38, it is 8-bit data line, display 2 lines, 5*7 dot matrix characters
        delay1(50); 
        LCD_write_command(0x0C); // Turn on display, turn off cursor, no blinking
        delay1(50);  
        LCD_write_command(0x06); // Set input mode, increment without displacement
        delay1(50); 
        LCD_write_command(0x01); // Clear screen
        delay1(50);
}








//*************************************** Display the string at the specified position ******************************************


void Write_LCD(int x, int y, char *str)
{
        char addr;
        if(x < 0)
        {
                x = 0;
        }
        if(x > 15)
        {
                x = 15;
        }
        if(y<0)
        {
                s++;
        } }                 //********************************* Display a character at the specified position         ***************************************          /         *
        void         Print_Char (unsigned char line ,unsigned char num,unsigned char date)         {         LCD_write_command         (         line                 + num )         ;                 LCD_write_data                  (                 date);                 }         * / // Display a character at the specified position ( for 1602 LCD ) -used in temperature displayvoid DisplayOneChar(unsigned char X, unsigned char Y, unsigned char DData) { Y &= 0x1; X &= 0xF; //Limit X not to be greater than 15, Y not to be greater than 1 if (Y) X |= 0x40; //When the second line is to be displayed, the address code + 0x40; X |= 0x80; //Calculate the command code LCD_write_command(X); //Do not detect the busy signal here, send the address code LCD_write_data(DData); }