#include<reg51F.h> // include P89V51rd2 SFR header file sbit LCD_RS = P1^6; // lcd command word/!data word select (register select) pin sbit LCD_RW = P1^5; // lcd read/!write pin (normally conn to gnd) sbit LCD_E = P1^7; // lcd enable pin sbit ROW4 = P0^7; // row 4 sbit ROW3 = P0^6; // row 3 sbit ROW2 = P0^5; // row 2 sbit ROW1 = P0^4; // row 1 sbit COL4 = P0^3; // col 4 sbit COL3 = P0^2; // col 3 sbit COL2 = P0^1; // col 2 sbit COL1 = P0^0; // col 1 bdata char flag; sbit keyflg = flag^0; // to indicate any key is pressed or not sbit sec_flg = flag^1; // 360 millisecond flag for key scanning

unsigned char data word[16]; // array defined of char type length 16 bytes unsigned char data i, cdelay; unsigned char data cw, dw, key,cursor; unsigned int data delay, sec; unsigned char code enterword[] = "* Enter number *";

void lcd_cw(cw) // lcd command word write { LCD_RS = 0; // commmand word select LCD_E = 1; P2 = cw; LCD_E = 0; for( delay=0; delay<=250; delay++); } void lcd_dw(dw) // lcd data word write { LCD_RS = 1; // data word select LCD_E = 1; P2 = dw; LCD_E = 0; for( delay=0; delay<=250; delay++); } void lcd_init() // lcd initialisation { lcd_cw(0x38); // for( delay=0; delay<=250; delay++); lcd_cw(0xe); // for( delay=0; delay<=250; delay++); lcd_cw(0x6); // for( delay=0; delay<=250; delay++); lcd_cw(0x1); // for( delay=0; delay<=250; delay++); lcd_cw(0x80); // for( delay=0; delay<=250; delay++); } disp_enterword() // { lcd_cw(0xc0); for(i=0; i<16; i++) { dw = enterword[i]; lcd_dw(dw); } } keyscan() // in normal operation execute this loop in every 2 milli seconds {

P0 = 0xff; ROW1 = 0; if( COL1 == 0 ) // D key { keyflg = 1; key = 'D'; } else if( COL2 == 0 ) // E key { keyflg = 1; key = 'E'; } else if( COL3 == 0 ) // F key { keyflg = 1; key = 'F'; } else if( COL4 == 0 ) // 0 key { keyflg = 1; key = '0'; } else { ROW2 = 0; if( COL1 == 0 ) // 9 key { keyflg = 1; key = '9'; } else if( COL2 == 0 ) // A key { keyflg = 1; key = 'A'; } else if( COL3 == 0 ) // B key { keyflg = 1; key = 'B'; } else if( COL4 == 0 ) // C key { keyflg = 1; key = 'C'; } else { P0 = 0xff; ROW3 = 0; if( COL1 == 0 ) // 5 key { keyflg = 1; key = '5'; } else if( COL2 == 0 ) // 6 key { keyflg = 1; key = '6'; } else if( COL3 == 0 ) // 7 key { keyflg = 1; key = '7'; } else if( COL4 == 0 ) // 8 key { keyflg = 1; key = '8'; } else { P0 = 0xff; ROW4 = 0; if( COL1 == 0 ) // 1 key { keyflg = 1; key = '1'; } else if( COL2 == 0 ) // 2 key { keyflg = 1; key = '2'; } else if( COL3 == 0 ) // 3 key { keyflg = 1; key = '3'; } else if( COL4 == 0 ) // 4 key { keyflg = 1; key = '4'; } } } } if( keyflg ) // if any new alphabet is pressed { keyflg = 0; ROW1 = 1; ROW2 = 1; ROW3 = 1; ROW4 = 1; dw = key; lcd_dw(dw); lcd_cw(0x80+cursor); // shift cursor by 1 word[cursor] = key; // store to display that alphabet/muneric to the lcd cursor++; if(cursor==16) // claer all row of lcd if line full { for( cdelay=0; cdelay<16; cdelay++ ) { lcd_cw(0x80+cdelay); lcd_dw(0x20); // clear command for lcd } cursor=0; lcd_cw(0x80); // shift cursor by 1 } lcd_cw(0x80+cursor); // shift cusor by 1 for( cdelay=0; cdelay<100; cdelay++ ); } } void main() { LCD_RW = 0; // set lcd in write mode lcd_init(); // initiallize lcd P0 = 0xff; // set port0 as an input port TMOD = 0x01; // timer0 in mode1 16 bit TH0 = 0xF8; // set higher reg of timer0 with 0xf8 TL0 = 0xCD; // set lower reg of timer0 with 0xcd for generating // 2msec delay at 11.0592 MHZ TR0 = 1; // start timer0 IE = 0x82; // set globle enable & timer0 enable pins disp_enterword(); // displays " Enter word " to lcd lcd_cw(0x80); // call the cursor at location 0x80 i.e. 1st line 1st position cursor = 0; // clear cursor position counter key = 0xff; // set key register while(1) { if( sec_flg) // this flag will set in every 360 milli second { sec_flg = 0; // clear flag keyscan(); // call key scan function } } } void tim0() interrupt 1 // 2mS timer { TH0 = 0xF8; // reload th0 by 0xf8 TL0 = 0xCD; // relaod tl0 by 0ccd if( sec++ >160) { sec = 0; // clear sec register sec_flg = 1; // 360ms flg } }
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