lcd_1602.h

利用时间片思想设计的一个AVR单片机的时钟程序

#define LCD_RS_DDR     DDRA
#define LCD_RS_PORT    PORTA	//数据/命令
#define LCD_RS         0x08     //portA3         out

#define LCD_RW_DDR     DDRA
#define LCD_RW_PORT    PORTA	//读/写
#define LCD_RW         0x04     //portA2         out

#define	LCD_EN_DDR     DDRA
#define LCD_EN_PORT    PORTA    //使能信号
#define LCD_EN         0x02     //portA1         out

#define LCD_DATA_PORT  PORTA
#define LCD_DATA_DDR   DDRA
#define LCD_DATA_PIN   PINA
#define LCD_DATA       0xf0    //portA4/5/6/7   out
#define	LCD_BUSY	  7    //portA7

/*--------------------------------------------------------------------------------------------------
Public function prototypes
--------------------------------------------------------------------------------------------------*/
void LCD_init         (void);
void LCD_en_write     (void);
unsigned char LCD_write_char   (unsigned command,unsigned data);
unsigned char LCD_wait_Ready   (void);
void LCD_set_xy       (unsigned char x, unsigned char y);
unsigned char LCD_write_string (unsigned char X,unsigned char Y,unsigned char *s);
unsigned char LCD_write_uint8(unsigned char X, unsigned char Y, unsigned int data, unsigned char num);
void delay_nus        (unsigned int n);
void delay_nms        (unsigned int n);

/**********************************************************
光标命令
LCD_write_char(0x0e,0);    //光标开
LCD_write_char(0x0d,0);    //光标所在字符闪烁  
LCD_write_char(0x0c,0);    //光标关  
**********************************************************/
/**********************************************************
TC1602B LCD DISPLAY
建立时间：2003年11月9号
修改日期：2003年11月14号
LCD_write函数功能：当command＝0时，向LCD写入数据，否则向LCD写
                   入命令
LCD第一行显示寄存器地址：0X80-0X8F
LCD第二行显示寄存器地址：0XC0-0XCF
**********************************************************/
void LCD_init(void)
{   //初始化端口方向
	LCD_EN_DDR |= LCD_EN;	  //输出
	LCD_RW_DDR |= LCD_RW;	
	LCD_RS_DDR |= LCD_RS;	
        LCD_DATA_DDR |= LCD_DATA;

	LCD_EN_PORT &= ~LCD_EN;   //端口清零
        LCD_RW_PORT &= ~LCD_RW;
        LCD_RS_PORT &= ~LCD_RS;	
	delay_nms(25);

    LCD_write_char(0x28,0);      //4bit test
    LCD_write_char(0x0c,0);      //显示开
    LCD_write_char(0x01,0);      //显示清屏
    LCD_write_char(0x06,0);      //显示光标移动设置
}


void LCD_en_write(void)        //EN端产生一个高电平脉冲，写LCD
{   LCD_EN_PORT |= LCD_EN;
    delay_nus(2);
    LCD_EN_PORT &= ~LCD_EN;
}


/*-----------------------------------------------------------------------
LCD_write_char    : 英文字符串显示函数

输入参数：*s      ：英文字符串指针；
          X、Y    : 显示字符串的位置，X:0-15，Y:0-1
                    LCD第一行显示寄存器地址：0X80-0X8F
                    LCD第一行显示寄存器地址：0XC0-0XCF	
-----------------------------------------------------------------------*/
unsigned char LCD_write_char(unsigned command,unsigned data)
{   unsigned command_temp,data_temp;  
      
    command_temp = command;
    data_temp = data;
   
    if( LCD_wait_Ready() == 1 )
    {	return(1);	}
    
	LCD_RW_PORT &= ~LCD_RW;                 //RW=0
	if (command == 0)
	{	LCD_RS_PORT |= LCD_RS;          //RS=1 
		asm("nop");
		LCD_DATA_PORT &= ~LCD_DATA;     //高4位清零
		asm("nop");
		LCD_DATA_PORT |= (data_temp>>(7-LCD_BUSY)) & LCD_DATA;   //取高4位
		asm("nop");
	}
	else 
	{	LCD_RS_PORT &= ~LCD_RS;            //RS=0
		asm("nop");
		LCD_DATA_PORT &= ~LCD_DATA;
		asm("nop");
	   	LCD_DATA_PORT |= (command_temp>>(7-LCD_BUSY)) & LCD_DATA; //取高4位
	   	asm("nop");
	}
    LCD_en_write();  //发送高4位
   
    command_temp=command_temp << 4;         //将低4位变为高4位
    data_temp=data_temp       << 4;
   
    LCD_DATA_PORT &= ~LCD_DATA;
    if (command==0)
    {	
    	LCD_DATA_PORT |= (data_temp>>(7-LCD_BUSY)) & LCD_DATA;	
    }
    else
    {
    	LCD_DATA_PORT |= (command_temp>>(7-LCD_BUSY)) & LCD_DATA;	
    }
    LCD_en_write();   //发送低4位
   
    LCD_RW_PORT |= LCD_RW;  //RW=1
	asm("nop");  
    LCD_RS_PORT ^= LCD_RS;  
    
    return(0);
}


#define	LCD_ERROR_TIME	1000
unsigned char LCD_wait_Ready(void)         //等待LCD空闲
{   unsigned int	temp;
    LCD_DATA_DDR &= ~(1<<LCD_BUSY);       //PD7 I/O口方向设置为输入
    asm("nop");
    LCD_RW_PORT |= LCD_RW;                //RW=1
    asm("nop");
    LCD_RS_PORT &= ~LCD_RS;              //RS=0
    asm("nop");
    LCD_EN_PORT |= LCD_EN;              //EN=1
	asm("nop");
	while (!( LCD_DATA_PIN&(1<<LCD_BUSY) ) == 0)   //RW=1,读PD7，为0表示空闲；
	{	temp ++;
		if( temp > LCD_ERROR_TIME )
		{	return(1);	}
	}
	asm("nop");
	LCD_EN_PORT &= ~LCD_EN;                //EN=0 
	asm("nop");
	LCD_DATA_DDR |= (1<<LCD_BUSY);   //重新将PD7设置位输出
	return(0);
}

/*-----------------------------------------------------------------------
LCD_set_xy        : 设置LCD显示的起始位置

输入参数：x、y    : 显示字符串的位置，X:0-15，Y:0-1
                    LCD第一行显示寄存器地址：0X80-0X8F
                    LCD第一行显示寄存器地址：0XC0-0XCF
	
-----------------------------------------------------------------------*/
void LCD_set_xy( unsigned char x, unsigned char y )
{	unsigned char address;
	if (y == 0) address = 0x80 + x;
	else 
	address = 0xc0 + x;
	LCD_write_char( address, 0 );
}


/*-----------------------------------------------------------------------
LCD_write_string  : 英文字符串显示函数

输入参数：*s      ：英文字符串指针；
          X、Y    : 显示字符串的位置

编写日期          ：2004-8-19 
最后修改日期      ：2004-8-19 		
-----------------------------------------------------------------------*/
unsigned char LCD_write_string(unsigned char X,unsigned char Y,unsigned char *s)
{   LCD_set_xy( X, Y );
    while (*s) 
    {	if( LCD_write_char( 0, *s ) == 1 )
    	{	return( 1 );	}
		s ++;
    }
    return( 0 );
}


/*-------------------------------------------------------------------------------*/
unsigned char LCD_write_uint8(unsigned char X, unsigned char Y, unsigned int data, unsigned char num)
{	unsigned char tempbuf[4],i;
	tempbuf[0]=(data/1000)+'0';
	tempbuf[1]=((data%1000)/100)+'0';
	tempbuf[2]=(data%100)/10+'0';
	tempbuf[3]=data%10+'0';
	LCD_set_xy( X, Y );
	for( i=0; i<num; i++ )
	{	if( LCD_write_char( 0, tempbuf[(4-num)+i] ) == 1 )	{	return( 1 );	}	}
	return(0);
}


/*-----------------------------------------------------------------------
延时函数
系统时钟：8M
-----------------------------------------------------------------------*/
void delay_1us(void)                 //1us延时函数
{   asm("nop");  }

void delay_nus(unsigned int n)       //N us延时函数
{   unsigned int i=0;
	for (i=0;i<n;i++)
   	delay_1us();
}

void delay_1ms(void)                 //1ms延时函数
{	unsigned int i;
   	for (i=0;i<1140;i++);
}
  
void delay_nms(unsigned int n)       //N ms延时函数
{	unsigned int i=0;
   	for (i=0;i<n;i++)
   	delay_1ms();
}