1602相关知识及四线驱动程序

今天在调1602显示的时候又费了点小周折，由于平常我们一般是对液晶进行写操作，所以在有的开发板上这个引脚直接是接地的，今天自己用杜邦线连了个1602忽略了这个问题，后来接地就好了。

数据传输的四线接法和八线接法差别在于写数据的顺序，下面附上四线接法的程序。

[cpp] view plaincopy/*--------------------------------------------------------------*/

//Name: LCD1602四线驱动程序

//File: LCD1602_4.H

//Date: 11-2-9

//TimE: 12:42

//Ver: 0.1

/*--------------------------------------------------------------*/

#include "reg51.h"

#include

//LCD1602接口定义

#define LCD_DATA P1 //P1口(P14~P17)与LCD高四位(D4~D7)对应相接

sbit LCD1602_RS=P1^2; //数据指令

sbit LCD1602_EN=P1^3; //使能

//延时函数,12mhz 6t延迟时间10*255us

void LCD_init(void);

void LCD_en_write(void);

void LCD_write_command(unsigned char command) ;

void LCD_write_data(unsigned char Recdata);

void LCD_set_xy (unsigned char x, unsigned char y);

void LCD_write_string(unsigned char X,unsigned char Y,unsigned char *s);

void LCD_write_char(unsigned char X,unsigned char Y,unsigned char Recdata);

void delay_nus(unsigned int n);

void delay_nms(unsigned int n);

//以下函数用于输出字符串和数字

int LCD_PutNum(unsigned long num,int XS,int pos);

int LCD_PutStr(unsigned char *DData,int pos);

//-------------------------1us延时函数---------------------------------

void delay_1us(void)

{

_nop_();

}

//------------------------N us延时函数---------------------------------

void delay_nus(unsigned int n)

{

unsigned int i=0;

for (i=0;i

delay_1us();

}

//-----------------------1ms延时函数----------------------------------

void delay_1ms(void)

{

unsigned int i;

for (i=0;i<1140;i++);

}

//-----------------------N ms延时函数---------------------------------

void delay_nms(unsigned int n)

{

unsigned int i=0;

for (i=0;i

delay_1ms();

}

//------------------------液晶初始化-----------------------------------

void LCD_init(void)

{

LCD_write_command(0x28);

delay_nus(40);

LCD_write_command(0x28);

delay_nus(40);

LCD_write_command(0x28);

delay_nus(40);

LCD_en_write();

delay_nus(40);

LCD_write_command(0x28); //4位显示

LCD_write_command(0x0c); //显示开

LCD_write_command(0x01); //清屏

delay_nms(2);

}

//----------------------液晶使能函数-------------------------------------

void LCD_en_write(void)

{ //EN由高电平跳变到低电平时液晶使能

LCD1602_EN=1;

delay_nus(1);

LCD1602_EN=0;

}

//------------------------写指令函数--------------------------------------

void LCD_write_command(unsigned char command)

{

delay_nus(16);

LCD1602_RS=0; //RS=0

LCD_DATA &=0X0f; //清高四位

LCD_DATA|=command&0xf0; //写高四位

LCD_en_write();

command=command<<4; //低四位移到高四位

LCD_DATA&=0x0f; //清高四位

LCD_DATA|=command&0xf0; //写低四位

LCD_en_write();

}

//------------------------写数据函数--------------------------------------

void LCD_write_data(unsigned char Recdata)

{

delay_nus(16);

LCD1602_RS=1; //RS=1

LCD_DATA&=0X0f; //清高四位

LCD_DATA|=Recdata&0xf0; //写高四位

LCD_en_write();

Recdata=Recdata<<4; //低四位移到高四位

LCD_DATA&=0X0f; //清高四位

LCD_DATA|=Recdata&0xf0; //写低四位

LCD_en_write();

}

//-----------------------地址定位函数-------------------------------------

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_command(address);

}

//----------------------在某个地址处，写一个字符----------------------------[!--empirenews.page--]

void LCD_write_char(unsigned char X,unsigned char Y,unsigned char Recdata) //列x=0~15,行y=0,1

{

LCD_set_xy(X, Y); //写地址

LCD_write_data(Recdata);

}

//----------------------------输出字符串-------------------------------------

int LCD_PutStr(unsigned char *DData,int pos) //pos表示字符显示位置，0~31

{

unsigned char i;

if(pos==-1)

{

LCD_write_command(0x01); //清屏

delay_nms(2);

pos=0;

}

while((*DData)!='')

{

switch(*DData)

{

case 'n': //如果是n，则换行

{

if(pos<17)

{

for(i=pos;i<16;i++) LCD_write_char(i%16, i/16,' ');

pos=16;

}

else

{

for(i=pos;i<32;i++) LCD_write_char(i%16, i/16,' ');

pos=0;

}

break;

}

case 'b': //如果是b，则退格

{

if(pos>0) pos--;

LCD_write_char(pos%16, pos/16, ' ');

break;

}

default:

{

if((*DData)<0x20) //小于0x20的显示不了?

{

*DData=' ';

}

LCD_write_char(pos%16, pos/16,*DData);

pos++;

break;

}

}

DData++;

}

return(pos);

}

//----------------------------输出数字---------------------------------

//这段程序写法我的理解大致是这样：num为去掉小数点之后的数字，XS为小数点

//从左数第几位，pos为显示的位置

//---------------------------------------------------------------------

int LCD_PutNum(unsigned long num,int XS,int pos)

{

unsigned long tmp=0;

unsigned char numbits=0; //总数字位数

if(pos==-1)

{

LCD_write_command(0x01);

delay_nms(2);

pos=0;

}

if(num==0)

{

LCD_write_char(pos%16, pos/16, '0');

pos++;

}

else

{

if(num<0)

{

LCD_write_char(pos%16, pos/16, '-');

num*=(-1);

pos++;

}

while(num) //例如数字1234，经过这个运算变成了4321

{

tmp=tmp*10+(num%10);

num=num/10;

numbits++;

}

while(tmp)

{

LCD_write_char(pos%16, pos/16, (tmp%10)+48);

tmp=tmp/10;

pos++;

numbits--;

if(numbits==XS) pos=LCD_PutStr(".",pos); //插入小数点

}

while(numbits--)

{

LCD_write_char(pos%16, pos/16, '0');

pos++;

}

}

return(pos);

}