Scroll and stop text on LCD

Projects Programming
26

I was thinking and I add on the beginning:

if (adc_key_in > 1000) return btnNONE; 

    // For V1.1 us this threshold
    if (adc_key_in < 50)   return btnRIGHT;  
    if (adc_key_in < 250)  return btnUP; 
    if (adc_key_in < 450)  return btnDOWN; 
    if (adc_key_in < 650)  return btnLEFT; 
    if (adc_key_in < 850)  return btnSELECT;

Here is all the code:

#include <LiquidCrystal.h>

LiquidCrystal lcd(8, 9, 4, 5, 6, 7);           // select the pins used on the LCD panel
// LiquidCrystal(rs, enable, d4, d5, d6, d7) 

// define some values used by the panel and buttons
int lcd_key     = 0;
int adc_key_in  = 0;

#define btnRIGHT  0
#define btnUP     1
#define btnDOWN   2
#define btnLEFT   3
#define btnSELECT 4
#define btnNONE   5

int read_LCD_buttons(){               // read the buttons
    adc_key_in = analogRead(0);       // read the value from the sensor 

    // my buttons when read are centered at these valies: 0, 144, 329, 504, 741
    // we add approx 50 to those values and check to see if we are close
    // We make this the 1st option for speed reasons since it will be the most likely result

    if (adc_key_in > 1000) return btnNONE; 

    // For V1.1 us this threshold
    if (adc_key_in < 50)   return btnRIGHT;  
    if (adc_key_in < 250)  return btnUP; 
    if (adc_key_in < 450)  return btnDOWN; 
    if (adc_key_in < 650)  return btnLEFT; 
    if (adc_key_in < 850)  return btnSELECT;  

    return btnNONE;                // when all others fail, return this.
}

void setup(){
   lcd.begin(16, 2);               // start the library
 }
 
void loop(){
static int i = 0;
static int a = 0;             // move cursor to second line "1" and 9 spaces over
  lcd.setCursor(i,a); 
   lcd.print("x");       // display seconds elapsed since power-up
   //lcd.print(adc_key_in);

   lcd_key = read_LCD_buttons();   // read the buttons

   switch (lcd_key){               // depending on which button was pushed, we perform an action
    
        case btnRIGHT:{             
            lcd.setCursor(i++, a);
            break;
       }
       case btnLEFT:{
             lcd.setCursor(i--, a); 
             break;
       }    
       case btnUP:{
             lcd.setCursor(i, a++);  
             break;
       }
       case btnDOWN:{
             lcd.setCursor(i, a--);  
             break;
       }
       
   }
}

Now buttons are working, but when I press the button DOWN/UP I have all the LCD with "xxxx"