51 MCU C Programming (XI. Telephone dialing simulation LCD display)

*Created by   : jumpmysoul
*Completed date: 2009.06.06
*    Version : V1.0
*Functional description: Press a key on the phone keypad, and the corresponding
character of the pressed key will be displayed on the LCD screen. Press the DEL key to delete a character (Disadvantage: After deleting all characters,
the cursor disappears. If you continue to delete several times, you will have to press the key several more times when entering again)

#include
#define uchar unsigned char
#define uint unsigned int
#define LCDPORT P0
#define KEY  P1
//#define WEI  P2

sbit DEL=P3^0;
sbit LCDE=P3^5;
sbit LCDRW=P3^6;
sbit LCDRS=P3^7;

uchar code NUM[12]="0123456789*#";

fly addr=0;

void WriteCMD(uchar);  
void init();
void WriteData(uchar);
void Delete();

void Delay_ms(uint);
uchar KeyScan();
void main()
{
 init();
 while(1)
 {
  if(KeyScan()!=20)   //Judge whether the phone key is pressed
  {
   addr++;     //Add 1 to the address variable
   WriteData(NUM[KeyScan()]);   //Display the pressed key value on the LCD
   Delay_ms(100);      //Delay, the function is to display only one character, if there is no delay, a string of characters will be displayed
  }

  if(DEL==0)      //Judge whether the DEL button is pressed
  {
   Delay_ms(10);
   if(DEL==0)
   while(DEL==0);
   Delay_ms(10);
   while(DEL==0);
   Delete();
  }
 }

}
uchar KeyScan()
{
 uchar temp=20;
 KEY=0xef;       //扫描第1列键
 switch(KEY)
 {
  case 0xee:temp=1;break;
  case 0xed:temp=4;break;
  case 0xeb:temp=7;break;
  case 0xe7:temp=10;break;
  default:break;
 } 
 KEY=0xdf;       //扫描第2列键
 switch(KEY)
 {
  case 0xde:temp=2;break;
  case 0xdd:temp=5;break;
  case 0xdb:temp=8;break;
  case 0xd7:temp=0;break;
  default:break;
 } 
 KEY=0xbf;       //扫描第3列键
 switch(KEY)
 {
  case 0xbe:temp=3;break;
  case 0xbd:temp=6;break;
  case 0xbb:temp=9;break;
  case 0xb7:temp=11;break;
  default:break;
 }
 return(temp);      //返回按键键值
}
void Delay_ms(uint x)
{
 uint i,j;
 for(i=x;i>0;i--)
  for(j=120;j>0;j--);
}
void WriteCMD(uchar Command)      
{
 Delay_ms(10);    //先延时。

 LCDE=1;      //Then change LCD to write command status.
 LCDRS=0;
 LCDRW=0;

 LCDPORT=Command;   //Output command again.

 LCDE=0;      //Finally execute the command.
}
void WriteData(uchar dat)       
{
 Delay_ms(10);       //Delay first.

 LCDE=1;        //Then change the LCD to write data state.
 LCDRS=1;
 LCDRW=0;

 LCDPORT=dat;      //Output data again.

 LCDE=0;        //Finally display the data.
}
void init()
{
 LCDRW=0;
    LCDE=0;
  WriteCMD(0x38);
 WriteCMD(0x0f);
 WriteCMD(0x06);
 WriteCMD(0x01);
 WriteCMD(0x80);
}
void Delete()
{
 if( (addr--)>0)
 {
  WriteCMD(0x04);     //After reading and writing a character, the address pointer decreases by 1 and the cursor moves left
  WriteData(' '); 
 }
 WriteCMD(0x06);      //After reading and writing a character, the address pointer increases by 1 and the cursor moves right
 
}