LCD1602

liquid crystal display 液晶显示屏，一种字符型液晶显示模块，可以显示 16*2 个字符，每个字符是 5*7 点阵。

P0 P2 会和数码管、LED 一定程度上冲突。

1. 地。

2. Vcc。

3. 调对比度的。

4. RS：数据指令端。1代表 DB 是数据，0代表是指令。

5. RW：1读0写。

6. E：类似时钟的使能。高电平有效，下降沿执行。

7. DB：并行输入。一个字节长。

8. BG：背光灯电源。

内部结构图

类似 SMG，想显示1并不是直接输入1，而是操纵数码管右侧一竖被点亮。字模库起的就是这个作用，里面有固定的 ROM 和用户课自定义的 RAM。

DDRAM 长于屏幕，可以通过移平实现滚动效果。

AC address controller，可以自动移位写入数据。

字模库中的数据大多数和 ASCII 码是一样的。

指令

初始化指令

初始化要做哪些操作？

规定显示区域（如8位数据接口，2行显示，5*7点阵，即为0011 10xx，如果取0即为 0x38.）。

显示的模式设置（如开启显示，关闭光标，关闭光标闪烁：0000 1101，即 0x0D）。

进入模式设置（如读写后光标++，屏幕不动：0000 0110,0x06。如果是滚动屏幕则为）。

清屏（0x01）。

显示指令

先设置 DDRAM 初始地址，0x80|AC（开头的8是 DDRAM 固定指令信息不能改。后面的全是0，与 AC 光标位置做与，AC 不同位置的值见 DDRAM 地址表）.

然后发送数据。

时序

模块化

第一阶段我们先编写 LCD1602 模块化编程代码，这一部分主要显示静态内容，用于程序编写过程中显示变量进行调试。

目标模块化函数：

//LCD1602.h
#ifndef __LCD1602_H__
#define __LCD1602_H__#include "reg52.h"
#include "intrins.h"
sbit LCD_RS=P2^6;
sbit LCD_RW=P2^5;
sbit LCD_E=P2^7;
#define LCD_DATAPORT P0void LCD_Delay1ms();		//@11.0592MHz
void LCD_WriteCommand(unsigned char Command);
void LCD_WriteData(unsigned char Data);
void LCD_Init();
void LCD_SetCursor(unsigned char line, unsigned char column);
unsigned int LCD_Pow(unsigned char x, unsigned char y);
void LCD_ShowChar(unsigned char line, unsigned char column, unsigned char c);
void LCD_ShowString(unsigned char line, unsigned char column, unsigned char str[]);
void LCD_ShowNum(unsigned char line, unsigned char column, unsigned int num, unsigned char length);
void LCD_ShowSignedNum(unsigned char line, unsigned char column, int num, unsigned char length);
void LCD_ShowHexNum(unsigned char line, unsigned char column, unsigned int num, unsigned char length);
void LCD_ShowBinNum(unsigned char line, unsigned char column, unsigned int num, unsigned char length);
#endif

//LCD1602.c
#include "LCD1602.H"void LCD_Delay1ms()		//@11.0592MHz
{unsigned char i, j;_nop_();_nop_();_nop_();i = 11;j = 190;do{while (--j);} while (--i);
}void LCD_WriteCommand(unsigned char Command){LCD_RS=0;LCD_RW=0;LCD_E=0;LCD_DATAPORT=Command;LCD_Delay1ms();LCD_E=1;LCD_Delay1ms();LCD_E=0;
}void LCD_WriteData(unsigned char Data){LCD_RS=1;LCD_RW=0;LCD_E=0;LCD_DATAPORT=Data;LCD_Delay1ms();LCD_E=1;LCD_Delay1ms();LCD_E=0;
}void LCD_Init(){LCD_WriteCommand(0x38);LCD_WriteCommand(0x0C);LCD_WriteCommand(0x06);LCD_WriteCommand(0x01);
}void LCD_SetCursor(unsigned char line, unsigned char column){if(line==1){LCD_WriteCommand(0x80|(column-1));}else{LCD_WriteCommand(0x80|(column-1)+0x40);}
}unsigned int LCD_Pow(unsigned char x, unsigned char y){unsigned char i=y;unsigned int res=1;for(;i>0;i--)res*=x;return res;
}void LCD_ShowChar(unsigned char line, unsigned char column, unsigned char c){LCD_SetCursor(line, column);LCD_WriteData(c);
}void LCD_ShowString(unsigned char line, unsigned char column, unsigned char str[]){unsigned int i=0;LCD_SetCursor(line, column);while(str[i]!='\\0'){LCD_WriteData(str[i]);i++;}
}void LCD_ShowNum(unsigned char line, unsigned char column, unsigned int num, unsigned char length){unsigned char i;unsigned base;LCD_SetCursor(line, column);for(i=length;i>0;i--){base=LCD_Pow(10, i-1);LCD_WriteData(num/base%10+'0');	}
}void LCD_ShowBinNum(unsigned char line, unsigned char column, unsigned int num, unsigned char length){unsigned char i;unsigned char base;unsigned char single_num;LCD_SetCursor(line, column);for(i=length;i>0;i--){base=LCD_Pow(2, i-1);single_num=num/base%2+'0';LCD_WriteData(single_num);	}
}void LCD_ShowHexNum(unsigned char line, unsigned char column, unsigned int num, unsigned char length){unsigned char i;unsigned char base;unsigned char single_num;LCD_SetCursor(line, column);for(i=length;i>0;i--){base=LCD_Pow(16, i-1);single_num=num/base%16;if(single_num<=9)single_num+='0';else single_num+='A'-10;LCD_WriteData(single_num);	}
}void LCD_ShowSignedNum(unsigned char line, unsigned char column, int num, unsigned char length){unsigned char i;unsigned base;LCD_SetCursor(line, column);if(num>0)LCD_WriteData('+');else {LCD_WriteData('-');num=-num;}for(i=length;i>0;i--){base=LCD_Pow(10, i-1);LCD_WriteData(num/base%10+'0');	}
}

如果希望屏幕滚动，一定时间执行一次LCD_WriteCommand(0x18); 屏幕左移指令。