#include<lpc21xx.
h>
#include<stdio.h>
/******* FUNCTION PROTOTYPE*******/
void lcd_init(void);
void clr_disp(void);
void lcd_com(void);
void lcd_data(void);
void wr_cn(void);
void wr_dn(void);
void scan(void);
void get_key(void);
void display(void);
void delay(unsigned int);
void init_port(void);
unsigned long int scan_code[16]= {0x00EE0000,0x00ED0000,0x00EB0000,0x00E70000,
0x00DE0000,0x00DD0000,0x00DB0000,0x00D70000,
0x00BE0000,0x00BD0000,0x00BB0000,0x00B70000,
0x007E0000,0x007D0000,0x007B0000,0x00770000};
unsigned char ASCII_CODE[16]= {'0','1','2','3',
'4','5','6','7',
'8','9','A','B',
'C','D','E','F'};
unsigned char row,col;
unsigned char temp,flag,i,result,temp1;
unsigned int r,r1;
unsigned long int var,var1,var2,res1,temp2,temp3,temp4;
unsigned char *ptr,disp[] = "4X4 KEYPAD";
unsigned char disp0[] = "KEYPAD TESTING";
unsigned char disp1[] = "KEY = ";
int main()
{
// __ARMLIB_enableIRQ();
init_port(); //port intialisation
delay(3200); //delay
lcd_init(); //lcd intialisation
delay(3200); //delay
clr_disp(); //clear display
delay(500); //delay
//........LCD DISPLAY TEST.........//
ptr = disp;
temp1 = 0x81; // Display starting address
lcd_com();
delay(800);
while(*ptr!='\0')
{
temp1 = *ptr;
lcd_data();
ptr ++;
}
//........KEYPAD Working.........//
while(1)
{
get_key();
display();
}
} //end of main()
void get_key(void) //get the key from the keyboard
{
unsigned int i;
flag = 0x00;
IO1PIN=0x000f0000;
while(1)
{
for(row=0X00;row<0X04;row++) //Writing one for col's
{
if( row == 0X00)
{
temp3=0x00700000;
}
else if(row == 0X01)
{
temp3=0x00B00000;
}
else if(row == 0X02)
{
temp3=0x00D00000;
}
else if(row == 0X03)
{
temp3=0x00E00000;
}
var1 = temp3;
IO1PIN = var1; // each time var1 value is put to port1
IO1CLR =~var1; // Once again Conforming (clearing all other bits)
scan();
delay(100); //delay
if(flag == 0xff)
break;
} // end of for
if(flag == 0xff)
break;
} // end of while
for(i=0;i<16;i++)
{
if(scan_code[i] == res1) //equate the scan_code with res1
{
result = ASCII_CODE[i]; //same position value of ascii code
break; //is assigned to result
}
}
}// end of get_key();
void scan(void)
{
unsigned long int t;
temp2 = IO1PIN; // status of port1
temp2 = temp2 & 0x000F0000; // Verifying column key
if(temp2 != 0x000F0000) // Check for Key Press or Not
{
delay(1000); //delay(100)//give debounce delay check again
temp2 = IO1PIN;
temp2 = temp2 & 0x000F0000; //changed condition is same
if(temp2 != 0x000F0000) // store the value in res1
{
flag = 0xff;
res1 = temp2;
t = (temp3 & 0x00F00000); //Verfying Row Write
res1 = res1 | t; //final scan value is stored in res1
}
else
{
flag = 0x00;
}
}
} // end of scan()
void display(void)
{
ptr = disp0;
temp1 = 0x80; // Display starting address of first line
lcd_com();
while(*ptr!='\0')
{
temp1 = *ptr;
lcd_data();
ptr ++;
}
ptr = disp1;
temp1 = 0xC0; // Display starting address of second line
lcd_com();
while(*ptr!='\0')
{
temp1 = *ptr;
lcd_data();
ptr ++;
}
temp1 = 0xC6; //display address for key value
lcd_com();
temp1 = result;
lcd_data();
}
void lcd_init (void)
{
temp = 0x30;
wr_cn();
delay(3200);
temp = 0x30;
wr_cn();
delay(3200);
temp = 0x30;
wr_cn();
delay(3200);
temp = 0x20;
wr_cn();
delay(3200);
// load command for lcd function setting with lcd in 4 bit mode,
// 2 line and 5x7 matrix display
temp = 0x28;
lcd_com();
delay(3200);
// load a command for display on, cursor on and blinking off
temp1 = 0x0C;
lcd_com();
delay(800);
// command for cursor increment after data dump
temp1 = 0x06;
lcd_com();
delay(800);
temp1 = 0x80;
lcd_com();
delay(800);
}
void lcd_data(void)
{
temp = temp1 & 0xf0;
wr_dn();
temp= temp1 & 0x0f;
temp= temp << 4;
wr_dn();
delay(100);
}
void wr_dn(void) ////write data reg
{
IO0CLR = 0x000000FC; // clear the port lines.
IO0SET = temp; // Assign the value to the PORT lines
IO0SET = 0x00000004; // set bit RS = 1
IO0SET = 0x00000008; // E=1
delay(10);
IO0CLR = 0x00000008;
}
void lcd_com(void)
{
temp = temp1 & 0xf0;
wr_cn();
temp = temp1 & 0x0f;
temp = temp << 4;
wr_cn();
delay(500);
}
void wr_cn(void) //write command reg
{
IO0CLR = 0x000000FC; // clear the port lines.
IO0SET = temp; // Assign the value to the PORT lines
IO0CLR = 0x00000004; // clear bit RS = 0
IO0SET = 0x00000008; // E=1
delay(10);
IO0CLR = 0x00000008;
}
void clr_disp(void)
{
// command to clear lcd display
temp1 = 0x01;
lcd_com();
delay(500);
}
void delay(unsigned int r1)
{
for(r=0;r<r1;r++);
}
void init_port()
{
IO0DIR = 0x000000FC; //configure o/p lines for lcd
IO1DIR = 0XFFF0FFFF;
}
