Error in LCD while interfacing with ATmega 32

Question

I am trying to interface a normal keypad and LCD .where for example if i press '1' in keypad it will show 'one' in the display . if i press '=' it will show 'EQUAL' in Display . i developed below code . but after simulating , the LCD is showing Random text like picture below. i cant figure out what happened here.

#include <mega32.h>
#include <alcd.h>
#include <delay.h>

#define keypad_ddr DDRC
#define keypad_port PORTC
#define keypad_input PINC

void main(void)
{
keypad_ddr=0xF0;
lcd_init(16);

while(1)
        {
        lcd_clear();
       keypad_port=0b11100000;
       lcd_gotoxy(0,0);
       if(keypad_input.0==0)
        lcd_putsf("Seven");
       if(keypad_input.1==0)
        lcd_putsf("Four");
       if(keypad_input.2==0)
        lcd_putsf("One");
       if(keypad_input.3==0)
        lcd_putsf("ON/C");
       keypad_port=0b11010000;
       lcd_gotoxy(0,0);
       if(keypad_input.0==0)
        lcd_putsf("Eight");
       if(keypad_input.1==0)
        lcd_putsf("Five");
       if(keypad_input.2==0)
        lcd_putsf("Two");
       if(keypad_input.3==0)
        lcd_putsf("Zero"); 
      keypad_port=0b10110000;
       lcd_gotoxy(0,0);
       if(keypad_input.0==0)
        lcd_putsf("Nine");
       if(keypad_input.1==0)
        lcd_putsf("Six");
       if(keypad_input.2==0)
        lcd_putsf("Three");
       if(keypad_input.3==0)
        lcd_putsf("Equal");
      keypad_port=0b01110000;
       lcd_gotoxy(0,0);
       if(keypad_input.0==0)
        lcd_putsf("Division");
       if(keypad_input.1==0)
        lcd_putsf("Multiplication");
       if(keypad_input.2==0)
        lcd_putsf("Minus");
       if(keypad_input.3==0)
        lcd_putsf("Plus");
        delay_ms(1000);
        }
}

Simulation : (Look at the LCD)

Answer 1

You show no pullup resistors in your schematic, so this isn't going to work unless you enable the internal pullups of the MEGA32. To do this, you need to write ones to the input bits. In other words, whenever you change the column selector, the low-order bits should be 1111, not 0000.

For example:

  keypad_port = 0b11101111;