// MCU BASIC: https://www.basic4mcu.com
// DateTime : 2018-12-18 오후 2:45:46
// by Ok-Hyun Park
//
#include <avr/io.h>
#include <avr/interrupt.h>
#include <stdio.h>
#define F_CPU 16000000UL // 16 MHz
#include <util/delay.h>
//
#define Trigger_1      PORTF|=1 //초음파 트리거
#define Trigger_0      PORTF&=~1 //초음파 트리거
#define Echo(PINF&2)//초음파 에코
//
unsigned char pw[4];
//
int range=0,password=0;
char check=0,run=0;
//
char keyin(){
        PORTC=~0x80; _delay_us(1);
        if(!(PINC&8))return(1);
        PORTC=~0x40; _delay_us(1);
        if(!(PINC&4))return(0);
        PORTC=~0x20; _delay_us(1);
        if(!(PINC&8))return(9);
        if(!(PINC&4))return(6);
        if(!(PINC&2))return(7);
        if(!(PINC&1))return(8);
        PORTC=~0x10; _delay_us(1);
        if(!(PINC&8))return(5);
        if(!(PINC&4))return(2);
        if(!(PINC&2))return(3);
        if(!(PINC&1))return(4);
  return(10);
}
//
void HC_SR04(){
    _delay_ms(100);
    Trigger_1; _delay_us(10); Trigger_0; // 10uS
    while(!Echo); TCNT1=0; TCCR1B=2;
    while( Echo); TCCR1B=8;
    range=TCNT1/116; // Cm
}
//
ISR(TIMER1_COMPA_vect){ // 1ms // 세그먼트
  unsigned char x[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90}; //0,1,2,3,4,5,6,7,8,9
  unsigned char open[]={0xbf,0xc0,0x8c,0x84,0xc8}; //{-,o,p,e,n}
  strtic char c=0;
  PORTA=0;
  if(run){
    if(check){ PORTE=x[pw[c]]; }
    else     { PORTE=open[c]; }
    PORTA=8>>c;
    if(++c>3)c=0;
  }
}
//
int main(){
  char key;
  DDRF=1;                // PF0 ouput Trigger,PF1 input Echo
  PORTC=0x0F; DDRC=0xF0; // keypad
  DDRE=0xFF;  DDRA=0x0F; // 세그먼트
  TCCR0=0x0C; OCR0=249; TIMSK=2; //16000000/64/(1+249),1ms
  SREG=0x80;
  while(1){
    //--------------------------------------------------------
    HC_SR04();
    if(run<50){ run=1;          } // 50cm 이내로 접근하면 동작
    else      { run=0; check=0; } // 멀어지면 off
    //--------------------------------------------------------
    if(run){
      for(i=0;i<4;i++)pw[i]=0; // 버퍼 초기화
      key=10;
      while(key>9){ // 1번째 키 입력 대기
        key=keyin();
        HC_SR04();
        if(run>50)continue; // 멀어지면 종료
      }
      pw[0]=key;
      //
      key=10;
      while(key>9){ // 2번째 키 입력 대기
        key=keyin();
        HC_SR04();
        if(run>50)continue; // 멀어지면 종료
      }
      pw[1]=key;
      //
      key=10;
      while(key>9){ // 3번째 키 입력 대기
        key=keyin();
        HC_SR04();
        if(run>50)continue; // 멀어지면 종료
      }
      pw[2]=key;
      //
      key=10;
      while(key>9){ // 4번째 키 입력 대기
        key=keyin();
        HC_SR04();
        if(run>50)continue; // 멀어지면 종료
      }
      pw[3]=key;
      //---------------------
      if(pw[0]=1 && pw[1]=2 && pw[2]=3 && pw[3]=4)check=1; else check=0;
      for(i=0;i<4;i++)pw[i]=0; // 버퍼 초기화
    }
  }
}
 
LCD 빼고 나머지로 만들어봤습니다.