increment/decrement numbers on an lcd

[dawson]

Hi,
I have been try the experiments from rajbex and am currently trying to implement his latest experiment into my project.

I want to set a number in the eeprom and can do this thanks to rajbex. however if I want to change that number I am having difficulties.

I have the following code:

/*
  Project Name: Read/Write Internal EEPROM
  * Copyright:
     (c) Rajendra Bhatt, 2009.
 * Description:
     This code is an example of accessing internal EEPROM.

 * Test configuration:
     MCU:             PIC16F628
     Oscillator:      IntRC I/O
*/

// LCD connections definitions
sbit LCD_RS at RA0_bit;
sbit LCD_EN at RA1_bit;
sbit LCD_D4 at RB0_bit;
sbit LCD_D5 at RB1_bit;
sbit LCD_D6 at RB2_bit;
sbit LCD_D7 at RB3_bit;
sbit LCD_RS_Direction at TRISA0_bit;
sbit LCD_EN_Direction at TRISA1_bit;
sbit LCD_D4_Direction at TRISB0_bit;
sbit LCD_D5_Direction at TRISB1_bit;
sbit LCD_D6_Direction at TRISB2_bit;
sbit LCD_D7_Direction at TRISB3_bit;
// End LCD connections definitions
// Define Messages
char message1[] = "1.READ";
char message2[] = "2.INC";
char message3[] = "3.DEC";
char message4[] = "Set Temp:";

char digits[] = "0";
unsigned short  i, NUM ;
unsigned int ADD = 0x00, temp; // Start EEPROM Location


void main() {
CMCON  |= 7;      // Disable Comparators
TRISB = 0x0F;
PORTB = 0x00;
Lcd_Init();
start:
Lcd_Cmd(_LCD_CLEAR);               // Clear display
Lcd_Cmd(_LCD_CURSOR_OFF);          // Cursor off
Lcd_Out(1,1,message1);             // Write message1 in 1st row
Lcd_Out(1,8,message2);
Lcd_Out(2,1,message3);
do {
// Read Operation
if (Button(&PORTA, 2, 1, 0)) {  // Detect logical one to zero
      Delay_ms(300);
      Lcd_Cmd(_LCD_CLEAR);
      Lcd_Out(1,1,message4);
      NUM = EEPROM_Read(0x000);
      digits[0] = NUM+48;
      Lcd_Out(2,1,digits);
      
      delay_ms(1000);
      goto start;

     }
 //increment
 if (Button(&PORTA, 3, 1, 0)) {  // Detect logical one to zero
      NUM = EEPROM_Read(0x000)+1;
      EEPROM_Write(0x000,NUM);

      Lcd_Cmd(_LCD_CLEAR);
      Lcd_Out(1,1,message4);
      digits[0] = NUM+48;
      Lcd_Out(2,1,digits);
      
      delay_ms(1000);
      goto start;
  }
//decrement
   if (Button(&PORTA, 4, 1, 0)) {  // Detect logical one to zero
      NUM = EEPROM_Read(0x000)-1;
      EEPROM_Write(0x000,NUM);

      Lcd_Cmd(_LCD_CLEAR);
      Lcd_Out(1,1,message4);
      digits[0] = NUM+48;
      Lcd_Out(2,1,digits);
      
      delay_ms(1000);
      goto start;
  }
 } while(1);
}

The above code does work and when pressing the corresponding button the number is incresed or decreased, however I can only display numbners 0 - 9. I am led to believe that the next number 10 is being stored but I need to seperate it and display 1+48 and 0+48. How can I do this? Also I would like to be able to store and display negative numbers as I need a scale of -55 to +125

Thanks

 

[rajbex]

You will find the answer to extract and display the multiple digits in my other examples:

Experiments with PIC16F628A: Experiment No. 5: Multiplexed Seven Segment Displays
Experiments with PIC16F628A: Experiment No. 4 : Reading Temperature Values from DS1820 using 1-Wire Protocol

- Raj
Experiments with PIC16F628A

 

[dawson]

thanks for the advice I now have it working for +numbers but still having trouble with negative numbers. Also it displays as 001,010,100 etc how can I make it just display 1,10,100:

here is the code i have now:

/*
  Project Name: Read/Write Internal EEPROM
  * Copyright:
     (c) Rajendra Bhatt, 2009.
 * Description:
     This code is an example of accessing internal EEPROM.

 * Test configuration:
     MCU:             PIC16F628
     Oscillator:      IntRC I/O
*/

// LCD connections definitions
sbit LCD_RS at RA0_bit;
sbit LCD_EN at RA1_bit;
sbit LCD_D4 at RB0_bit;
sbit LCD_D5 at RB1_bit;
sbit LCD_D6 at RB2_bit;
sbit LCD_D7 at RB3_bit;
sbit LCD_RS_Direction at TRISA0_bit;
sbit LCD_EN_Direction at TRISA1_bit;
sbit LCD_D4_Direction at TRISB0_bit;
sbit LCD_D5_Direction at TRISB1_bit;
sbit LCD_D6_Direction at TRISB2_bit;
sbit LCD_D7_Direction at TRISB3_bit;
// End LCD connections definitions
// Define Messages
char message1[] = "1.READ";
char message2[] = "2.INC";
char message3[] = "3.DEC";
char message4[] = "Set Temp:";

char digits[] = "000";
unsigned short  i, NUM ;

void lcd_convert() {
     // check if temperature is negative
     if (NUM & 0x8000) {
        digits[0] = '-';
        // Negative temp values are stored in 2's complement form
        NUM = ~NUM + 1;
     }

     if (NUM/100)  {
        // 48 is the decimal character code value for displaying 0 on LCD
        digits[0] = NUM/100  + 48;
     }
     else   {
         digits[0] = '0';
         digits[1] = (NUM/10)%10 + 48;             // Extract tens digit
         digits[2] =  NUM%10     + 48;             // Extract ones digit
     }
}
void main() {
     CMCON  |= 7;      // Disable Comparators
     TRISB = 0x0F;
     PORTB = 0x00;
     Lcd_Init();
     start:
     Lcd_Cmd(_LCD_CLEAR);               // Clear display
     Lcd_Cmd(_LCD_CURSOR_OFF);          // Cursor off
     Lcd_Out(1,1,message1);             // Write message1 in 1st row
     Lcd_Out(1,8,message2);
     Lcd_Out(2,1,message3);
     do {
        // Read Operation
        if (Button(&PORTA, 2, 1, 0)) {  // Detect logical one to zero
           Delay_ms(300);
           NUM = EEPROM_Read(0x000);

           lcd_convert();

           Lcd_Cmd(_LCD_CLEAR);
           Lcd_Out(1,1,message4);
           Lcd_Out(2,1,digits);

           delay_ms(1000);
           goto start;
         }
         //increment
         if (Button(&PORTA, 3, 1, 0)) {  // Detect logical one to zero
            NUM = EEPROM_Read(0x000)+1;
            EEPROM_Write(0x000,NUM);

            lcd_convert();
            
            Lcd_Cmd(_LCD_CLEAR);
            Lcd_Out(1,1,message4);
            Lcd_Out(2,1,digits);

            delay_ms(1000);
            goto start;
          }
          //decrement
          if (Button(&PORTA, 4, 1, 0)) {  // Detect logical one to zero
             NUM = EEPROM_Read(0x000)-1;
             EEPROM_Write(0x000,NUM);

             lcd_convert();
             
             Lcd_Cmd(_LCD_CLEAR);
             Lcd_Out(1,1,message4);
             Lcd_Out(2,1,digits);

             delay_ms(1000);
             goto start;
           }
        } while(1);
}

 

[rajbex]

Try this.
1. Change unsigned short NUM to signed short NUM.
2. change the following code
else {
digits[0] = '0';
digits[1] = (NUM/10)%10 + 48; // Extract tens digit
digits[2] = NUM%10 + 48; // Extract ones digit
}

TO

else {
digits[1] = (NUM/10)%10 + 48; // Extract tens digit
digits[2] = NUM%10 + 48; // Extract ones digit
}

You will still see 0s but you should be able to display negative numbers. Give it a try.

- Raj
Experiments with PIC16F628A

 

[dawson]

Yeah that and another minor adjustment have solved the negative numbers issue thanks.

Any ideas on how to remove the extra 0's?

 

[rajbex]

There are many ideas, I would suggest you to explore this yourself.
Thank you.
-Raj
Experiments with PIC16F628A

 

[dawson]

I have been exploring and reading up on c programming, but have only been learning a few days and am struggling. I will continue to work on it and read the tutorials you suggested in an earlier post but so far I have not come across anything that will help me here.