*============================================================
使用1602液晶顯示的實驗例子 明浩 2004/2/27
==============================================================
SMC1602A(16*2)模擬口線接線方式
連接線圖:
---------------------------------------------------
|LCM-----51 　| LCM-----51　　|　LCM------51 |
---------------------------------------------|
|DB0-----P1.0 | DB4-----P1.4 | RW-------P2.0 |
|DB1-----P1.1 | DB5-----P1.5 | RS-------P2.1 |
|DB2-----P1.2 | DB6-----P1.6 | E--------P2.2 |
|DB3-----P1.3 | DB7-----P1.7 | VLCD接1K電阻到GND|
---------------------------------------------------

[注:AT89S51使用12M晶振]
=============================================================*/

#define LCM_RW P2_0 //定義引腳
#define LCM_RS P2_1
#define LCM_E P2_2
#define LCM_Data P1
#define Busy 0x80 //用于檢測LCM狀態(tài)字中的Busy標(biāo)識

#include <at89x51.h>

void WriteDataLCM(unsigned char WDLCM);
void WriteCommandLCM(unsigned char WCLCM,BuysC);
unsigned char ReadDataLCM(void);
unsigned char ReadStatusLCM(void);
void LCMInit(void);
void DisplayOneChar(unsigned char X, unsigned char Y, unsigned char DData);
void DisplayListChar(unsigned char X, unsigned char Y, unsigned char code *DData);
void Delay5Ms(void);
void Delay400Ms(void);

unsigned char code cdle_net[] = {"www.cdle.net"};
unsigned char code email[] = {"pnzwzw@cdle.net"};

void main(void)
{
Delay400Ms(); //啟動等待，等LCM講入工作狀態(tài)
LCMInit(); //LCM初始化
Delay5Ms(); //延時片刻(可不要)

DisplayListChar(0, 0, cdle_net);
DisplayListChar(0, 1, email);
ReadDataLCM();//測試用句無意義
while(1);
}

//寫數(shù)據(jù)
void WriteDataLCM(unsigned char WDLCM)
{
ReadStatusLCM(); //檢測忙
LCM_Data = WDLCM;
LCM_RS = 1;
LCM_RW = 0;
LCM_E = 0; //若晶振速度太高可以在這后加小的延時
LCM_E = 0; //延時
LCM_E = 1;
}

//寫指令
void WriteCommandLCM(unsigned char WCLCM,BuysC) //BuysC為0時忽略忙檢測
{
if (BuysC) ReadStatusLCM(); //根據(jù)需要檢測忙
LCM_Data = WCLCM;
LCM_RS = 0;
LCM_RW = 0;
LCM_E = 0;
LCM_E = 0;
LCM_E = 1;
}

//讀數(shù)據(jù)
unsigned char ReadDataLCM(void)
{
LCM_RS = 1;
LCM_RW = 1;
LCM_E = 0;
LCM_E = 0;
LCM_E = 1;
return(LCM_Data);
}

//讀狀態(tài)
unsigned char ReadStatusLCM(void)
{
LCM_Data = 0xFF;
LCM_RS = 0;
LCM_RW = 1;
LCM_E = 0;
LCM_E = 0;
LCM_E = 1;
while (LCM_Data & Busy); //檢測忙信號
return(LCM_Data);
}

void LCMInit(void) //LCM初始化
{
LCM_Data = 0;
WriteCommandLCM(0x38,0); //三次顯示模式設(shè)置，不檢測忙信號
Delay5Ms();
WriteCommandLCM(0x38,0);
Delay5Ms();
WriteCommandLCM(0x38,0);
Delay5Ms();

WriteCommandLCM(0x38,1); //顯示模式設(shè)置,開始要求每次檢測忙信號
WriteCommandLCM(0x08,1); //關(guān)閉顯示
WriteCommandLCM(0x01,1); //顯示清屏
WriteCommandLCM(0x06,1); // 顯示光標(biāo)移動設(shè)置
WriteCommandLCM(0x0C,1); // 顯示開及光標(biāo)設(shè)置
}

//按指定位置顯示一個字符
void DisplayOneChar(unsigned char X, unsigned char Y, unsigned char DData)
{
Y &= 0x1;
X &= 0xF; //限制X不能大于15，Y不能大于1
if (Y) X |= 0x40; //當(dāng)要顯示第二行時地址碼+0x40;
X |= 0x80; //算出指令碼
WriteCommandLCM(X, 0); //這里不檢測忙信號，發(fā)送地址碼
WriteDataLCM(DData);
}

//按指定位置顯示一串字符
void DisplayListChar(unsigned char X, unsigned char Y, unsigned char code *DData)
{
unsigned char ListLength;

ListLength = 0;
Y &= 0x1;
X &= 0xF; //限制X不能大于15，Y不能大于1
while (DData[ListLength]>0x20) //若到達字串尾則退出
{
if (X <= 0xF) //X坐標(biāo)應(yīng)小于0xF
{
DisplayOneChar(X, Y, DData[ListLength]); //顯示單個字符
ListLength++;
X++;
}
}
}

//5ms延時
void Delay5Ms(void)
{
unsigned int TempCyc = 5552;
while(TempCyc--);
}

//400ms延時
void Delay400Ms(void)
{
unsigned char TempCycA = 5;
unsigned int TempCycB;
while(TempCycA--)
{
TempCycB=7269;
while(TempCycB--);
};
}