Proteus8 simulation: 51 single-chip LCD1602 display

components

components	name
exclusion	RESPACK-8
51 MCU	AT89C51
LCD1602	LM016L
button	BUTTON

Schematic part

LCD1602 driver:
HD44780 display mainly has 8-bit operation, 8-bit two-line display, 4-bit operation, 8-bit one-line display, and 8-bit operation, 8-bit one-line display.
LCD1602 is mainly driven by HD44780, first check the HD44780 data sheet to see the function of related pins

pin	effect
RS	select register
RW	read-write control
EA	enable read and write
D0-D3	The lower four bits of the data line
D4-47	The high four bits of the data line

Then HD44780 has two 8-bit registers, IR and DR, IR write command, DR write data.

Register operation is controlled by the RS and RW bits.

RS	RW	effect
0	0	IR write internal operation
0	1	Read flag (DB7 busy bit) and DB0-DB6 address
1	1	DR read internal operation
1	0	DR write internal operation

Read timing + program

uint_8 Lcd1602_read(bit Flag)
{
    
    
	uint_8 Data;
	E=0;
	RW=1;
	if(Flag==1) RS=0;  //读繁忙位
	else RS=1; //读DR寄存器
	E=1;
	Data=P0;
	E=0;
	return Data;
}

Write timing + program

void Lcd1602_write(bit Comm,uint_8 Data)
{
    
    
	while(Lcd1602_read(1)==1);//如果繁忙就暂停
	E=0;
	RW=0;
	if(Comm==1) RS=0; //写指令
	else RS=1; //写数据
	E=1;
	P0=Data;
	E=0;
}

Then you can view the corresponding commands according to the data manual:

for the instructions, because the space is too long, I will choose a few to talk about:

#define Clear_Display 0X01  //清屏
#define Display_On 0X0E //打开屏幕显示光标不闪烁  
#define Display_Off 0X00 //关闭屏幕不显示光标不闪烁 
//0000 1DCB D:1打开显示0关闭显示 C:1打开光标0关闭光标 B:1光标闪烁0光标不闪
#define Bit8_Line2_Display 0X38 //8位2行显示
#define Entry_Mode_Set 0X06 //光标右移显示器不移动
//0000 0 1 I/D S //I/D1模式自增一向右0模式自减一向左 S1光标不移动显示器移动0显示器不移动
#define Set_CGRAM00 0X80 //第一行
#define Set_CGRAM10 0XC0 //第二行
#define Shift_Function 0X14 //光标右移

Then write the initialization code according to the data sheet (8-bit operation, 8-bit 2-line display):
It is worth noting that the FLAG (busy bit) cannot be read during the instruction operation. According to the data sheet, the busy bit is the highest of DB0-7 bit.

void Lcd1602_init(void)
{
    
    
	Lcd1602_write(1,Bit8_Line2_Display); //设置为8位2行显示
	Lcd1602_write(1,Set_CGRAM00);//起始位置设置
	Lcd1602_write(1,Display_On); //打开显示和光标
    Lcd1602_write(1,Shift_Function);//光标右移
	Lcd1602_write(1,Entry_Mode_Set);//光标右移显示器不移动
}

This is the font given in the manual.
Since CGRAM will generate fonts, it can automatically display string

display functions:

void Show_String(uint_8 *line1,uint_8 *line2)
{
    
    
	uint_8 i=0;
	Lcd1602_write(1,Set_CGRAM00);
	for(i=0;i<strlen(line1);i++)
	{
    
    
		Lcd1602_write(0,line1[i]);
	}
	Lcd1602_write(1,Set_CGRAM10);
	for(i=0;i<strlen(line2);i++)
	{
    
    
		Lcd1602_write(0,line2[i]);
	}	
}

the code

In this experiment, LCD1602 displays the time.

main.c

code show as below:

#include <reg51.h>
#include "string.h"

#define Clear_Display 0X01  //清屏
#define Display_On 0X0E //打开屏幕显示光标不闪烁  
#define Display_Off 0X00 //关闭屏幕不显示光标不闪烁 
//0000 1DCB D:1打开显示0关闭显示 C:1打开光标0关闭光标 B:1光标闪烁0光标不闪
#define Bit8_Line2_Display 0X38 //8位2行显示
#define Entry_Mode_Set 0X06 //光标右移显示器不移动
//0000 0 1 I/D S //I/D1模式自增一向右0模式自减一向左 S1光标不移动显示器移动0显示器不移动
#define Set_CGRAM00 0X80 //第一行
#define Set_CGRAM10 0XC0 //第二行
#define Shift_Function 0X14 //光标右移
#define Cursor_Close 0X0C

//-----------Writer:CSDN 月明Mo----------------------------------------------------------------------------------------------------------------------
//-----------引脚连接------------------------------------------------------------------------------------------------------------
//RS -------- P10
//选择寄存器。
//0: 指令寄存器（用于写入）繁忙标志：
//地址计数器（供阅读）
//1: 数据寄存器（用于写入和读取）

//RW -------- P11
//0 写
//1 读

//EA -------- P12
//使能读和写

//D0-D3 数据线低四位
//D4-47 数据线高四位
//D0 -------- P00 
//D1 -------- P01
//---------
//D7 -------- P07
sbit RS=P1^0;
sbit RW=P1^1;
sbit E=P1^2;

typedef unsigned char uint_8;
typedef unsigned int uint_16;

//------------函数说明-------------------------------------------------------------------------------------------------
void Lcd1602_init(void); //初始化函数
uint_8 Lcd1602_read(bit Flag); //Lcd1602读函数
//Flag为1时读取忙碌为
//为0时读取DR寄存器
void Lcd1602_write(bit Comm,uint_8 Data);
//Comm为1时写指令，为0写数据
//Data为要写的数据
void Lcd1602_Clear(void);
//清屏
void Show_String(uint_8 *line1,uint_8 *line2);
//line1为第一行要显示的字符
//line2为第二行要显示的字符


void tim_init(void);
void delay_ms(uint_16 ms);

uint_8 mcount=55,fcount=59,scount=23; //时间定义

void main(void)
{
    
    
	uint_8 a=0;
	uint_8 line1[]="    time show"; 
	uint_8 line2[]="    00:00:00"; 
	Lcd1602_init();
	tim_init();
	while(1)
	{
    
    
		//加48是因为0和’0‘的ASCII值差48，将数字变为字符
		line2[4]=scount/10+48; //显示时十位
		line2[5]=scount%10+48;//显示时个位
		line2[7]=fcount/10+48;//显示分十位
		line2[8]=fcount%10+48;//显示分个位
		line2[10]=mcount/10+48;//显示秒十位
		line2[11]=mcount%10+48;//显示秒个位
		if(mcount>=60){
    
    mcount=0;fcount++;}//秒大于60清零
		if(fcount>=60){
    
    fcount=0;scount++;}//分大于60清零
		if(scount>=24){
    
    scount=0;}//时大于24清零
		Show_String(line1,line2);
	};
}

void Show_String(uint_8 *line1,uint_8 *line2)
{
    
    
	uint_8 i=0;
	Lcd1602_write(1,Set_CGRAM00);
	for(i=0;i<strlen(line1);i++)
	{
    
    
		Lcd1602_write(0,line1[i]);
	}
	Lcd1602_write(1,Set_CGRAM10);
	for(i=0;i<strlen(line2);i++)
	{
    
    
		Lcd1602_write(0,line2[i]);
	}	
}

void Lcd1602_init(void)
{
    
    
	Lcd1602_write(1,Bit8_Line2_Display); //设置为8位2行显示
	Lcd1602_write(1,Set_CGRAM00);//起始位置设置
	Lcd1602_write(1,Display_On); //打开显示和光标
  Lcd1602_write(1,Shift_Function);//光标右移
	Lcd1602_write(1,Entry_Mode_Set);//光标右移显示器不移动
	Lcd1602_write(1,Cursor_Close);
}

void Lcd1602_Clear(void)
{
    
    
	Lcd1602_write(1,Clear_Display);
}

void Lcd1602_write(bit Comm,uint_8 Data)
{
    
    
	while(Lcd1602_read(1)==1);//如果繁忙就暂停
	E=0;
	RW=0;
	if(Comm==1) RS=0; //写指令
	else RS=1; //写数据
	E=1;
	P0=Data;
	E=0;
}

uint_8 Lcd1602_read(bit Flag)
{
    
    
	uint_8 Data;
	E=0;
	RW=1;
	if(Flag==1) RS=0;  //读繁忙位
	else RS=1; //读DR寄存器
	E=1;
	if(Flag==1)Data=((P0&0x80)>>7);
	else Data=P0;
	E=0;
	return Data;
}

//定时器中断50ms
uint_8 t;
void time() interrupt 1
{
    
    
	t++;//每50ms进来一次
	if(t>=20){
    
    t=0;mcount++;} //50×20 ==1000 == 1s，秒加一
}

//定时器0初始化函数
void tim_init(void)
{
    
    
	TH0=(65535-50000)/256; //设置初始时间高八位
	TL0=(65535-50000)%256; //设置初始时间低八位
	EA=1;//打开总中断
	ET0=1; //打开定时器0中断
	TMOD=0X01; //定时器模式选择
	TR0=1;//开始计数
}

//延时函数
void delay_ms(uint_16 ms)
{
    
    
	uint_16 i,j;
	for(i=0;i<ms;i++)
	for(j=71;j>0;j--);
}

The running effect is as shown in the figure:

Project Files

Project files include HD44780 files