LCD1602 Program

Configuration: 

 ATMega16L @3.3V @7.3728MHz 
 1602B LCD @5.0V @6 lines 
 Compiler: WinAVR 20060125 

I built a multi-purpose board myself, 1602 is powered by 5V, M16 is powered by 3.3V. In order to make the LCD work as soon as possible, and also because of laziness... I referred to many 1602 posts on the website, including website collection posts. After downloading the program, I modified it slightly, compiled it, and downloaded it to M16, but it always did not respond. 

During this process, I was sure that there was no problem with my 1602 hardware, because I had a time thermometer (1602+18B20) made with 51 before, and it could display normally when I put it on. 

During the whole process, I felt that whether it was the essence posts collected on the website or the 1602 programs in ordinary posts, they were long and complicated... For example, in a post, I saw a 1602 initialization function that actually used more than 10 lines of code! In 51, it only had 4 sentences... 


Later, I encountered the following program, which was concise and successful at one time. Of course, this is also copied from the forum, I made some modifications: 


#include  

#define LCD_EN_PORT PORTC 
#define LCD_RW_PORT PORTC 
#define LCD_RS_PORT PORTC 
#define LCD_DATA_PORT PORTA 
#define LCD_DATA_DDR DDRA 
#define LCD_DATA_ PIN    PINA 

//LCD's r/w pins are directly connected to GND 
#define LCD_EN 0x80 //portd7 out 
#define LCD_RS 0x40 //portc6 out 
#define LCD_DATA 0xF0 //porta 4/5/6/7 out 

/*-------------------------------------------------------------------------------------------------- 
Publ IC  function prototypes 
--------------------------------------------------------------------------------------------------*/ 
void LCD_init (void); 
void LCD_en_write (void); 
void LCD_write_char (unsigned command,unsigned data);  void
LCD_set_xy (unsigned char x, unsigned char y); 
LCD_write_string (unsigned char X,unsigned char Y,unsigned char *s); 
void delay_nus (unsigned int n); 
void delay_nms (unsigned int n); 


void LCD_init(void) //LCD initialization 
{ 
 delay_nms(15); 
  
 DDRA |= LCD_DATA; //Data is output 
 DDRC |= LCD_RS | LCD_EN; //Set RS.EN 
  
 LCD_write_char(0x28,0); //4-bit display 
 LCD_write_char(0x0c,0); //Display on 
 LCD_write_char(0x01,0); //Clear screen 
  
 delay_nms(60); 
} 

void LCD_write_string(unsigned char X,unsigned char Y,unsigned char *s) 
{ 
 LCD_set_xy( X, Y ); //Write address 
    
 while (*s) { 
    LCD_write_char( 0, *s ); 
   s ++; 
 } 
} 
   
void LCD_set_xy( unsigned char x, unsigned char y ) //Write address function 
{ 
 unsigned char address; 
  
 if (y == 0) 
   address = 0x80 + x; 
 else  
   address = 0xc0 + x; 
       
 LCD_write_char(address, 0 ); 
} 

void LCD_en_write(void) //LCD enable 
{ 
  LCD_EN_PORT |= LCD_EN; 
  delay_nus(1); 
  LCD_EN_PORT &= ~LCD _EN; 
} 
void LCD_write_char(unsigned command,unsigned data) //Write data 
{ 
 unsigned command_temp,data_temp; 
  
 command_temp = command; 
 data_temp = data; 
 delay_nus(16); 
  
 if(command == 0) { 
   LCD_RS_PORT |= LCD_RS; //RS=1 
   LCD_DATA_PORT &= 0X0f; 
   LCD_DATA_PORT |= data_temp & 0xf0; //Write the upper four bits 
    
   LCD_en_write(); 
    
   data_temp = data_temp << 4;   
   LCD_DATA_PORT &= 0X0f; 
   LCD_DATA_PORT |= data_temp & 0xF0; //Write the lower four bits 
    
   LCD_en_write(); 
 } 
 else { 
   LCD_RS_PORT &= ~LCD_RS; //RS=0 
   LCD_DATA_PORT &= 0X0f; 
   LCD_DATA_PORT |= command_temp & 0xF0; //Write the upper four bits 
    
   LCD_en_write(); 
    
   command_temp = command_temp << 4; 
   LCD_DATA_PORT &= 0x0F; 
   LCD_DATA_PORT |= command_temp & 0xF0 ; //Write the lower four bits 
    
   LCD_en_write(); 
  } 
} 



int main(void) 
{ 

 LCD_init(); 
  
 LCD_write_string(0,0,"Hello,AVR WORLD!!!"); 
 LCD_write_string(0,1,"hitro@tom.com"); 

 while(1); 
  
} 
   /*--------------------------- -------------------------------------------- 
Delay function 
system clock: 8M 
------------------------------------------------- ----------------------*/ 
void delay_1us(void) //1us delay function 
  { 
   asm("nop"); 
  } 

void delay_nus(unsigned int n ) //N us delay function 
  { 
   unsigned int i=0; 
   for (i=0;i   delay_1us(); 
  } 
   
void delay_1ms(void) //1ms delay function 
  { 
   unsigned int i; 
   for ( i=0;i<1356;i++); 
  } 
   
void delay_nms(unsigned int n) //N ms delay function 
  { 
   unsigned int i=0; 
   for (i=0;i   delay_1ms(); 
  }