/*============================================================
        使用1602液晶顯示的實驗例子     
==============================================================
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  P1_1//定義引腳
#define LCM_RS  P1_2
#define LCM_E   P1_0
#define LCM_Data  P0
#define Busy    0x80 //用于檢測LCM狀態字中的Busy標識

#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
 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);
}

//寫數據
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; 
}

//讀數據
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
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); //三次顯示模式設置，不檢測忙信號
 Delay5Ms(); 
 WriteCommandLCM(0x38,0);
 Delay5Ms(); 
 WriteCommandLCM(0x38,0);
 Delay5Ms(); 

 WriteCommandLCM(0x38,1); //顯示模式設置,開始要求每次檢測忙信號
 WriteCommandLCM(0x08,1); //關閉顯示
 WriteCommandLCM(0x01,1); //顯示清屏
 WriteCommandLCM(0x06,1); // 顯示光標移動設置
 WriteCommandLCM(0x0C,1); // 顯示開及光標設置
}

//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坐標應小于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--);
 };
}