combo1.c

lcd temperature weight humidity

//Include required header files here.
#include "io16f877.h"
#define LCD_RS	RB4	// Register select
#define LCD_EN	RB5	// Enable
#define	LCD_STROBE	((LCD_EN = 1),(LCD_EN=0))

//This function is called to cause a delay of count Us.
void DelayUs(int count)
{
 int i;
 int j;
 for(i=0;i<count;i++)
 {
  for(j=0;j<5;j++);
  //This for loop has 5 NOPs & wastes 1 uS for our PIC clock frequency of 20MHz. 
 }
}

//This function is called to cause a delay of count Ms.
void DelayMs(int count)
{
 int i;
 int j;
 for(i=0;i<count;i++)
 {
  for(j=0;j<5000;j++);
  //This for loop has 5 NOPs & wastes 1 mS for our PIC clock frequency of 20MHz. 
 }
}
// This function initialize the IO ports
void initialize_IO_ports(void)
{TRISD=0xF0;    //-- Port D bit 0 to 3 as output (output to LCD)
 TRISB = 0x07;  //set port B as input
 PORTB = 0X00;
}

//This function sets up ADC & initialises it for use.
void initialize_ADC(void)
{
 TRISA = 0xFF ; //portA as input as we need the analog channel.
 //Configure portA as analog, VDD & VSS as VREFs; 
 ADCON1 = 0x82 ; // ADC result to be right-justified.
/************************************************************
Set AD conversion clock(TAD)to 32 times main clock freq as it should be 
at least 1.6 uS. System clock period for 20MHz crystal is 0.2uS.
************************************************************/
 ADCS1 = 1 ;
 ADCS0 = 0 ;
 //turn ON the ADC.
 ADON = 1 ;
}
//This function takes analog input from channel_number & returns the value.
int read_ADC(int channel_number)
{
 int value;  
 switch( channel_number)
 {case 0:
	CHS2=0;CHS1=0;CHS0=0;
	break;
  case 1:
	CHS2=0;CHS1=0;CHS0=1;
	break;
  case 2:
	CHS2=0;CHS1=1;CHS0=0;
	break;
  case 3:
	CHS2=0;CHS1=1;CHS0=1;
	break;
  default:
	CHS2=0;CHS1=0;CHS0=0;
 }//end switch case.
 DelayUs(100);
 // start AD conversion.
 GO=1;
 //Then, wait for conversion to finish.
 while(GO) {};
 //Finally, read the values in the A/D result register pair.
 value=(ADRESH<<8)+ADRESL;
 //wait for at least 2TAD. 
 DelayUs(4);
 return(value);
}

/* write a byte to the LCD in 4 bit mode */
void
lcd_write(unsigned char c)
{
	PORTD = (PORTD & 0xF0) |  (c >> 4);
	LCD_STROBE;
	PORTD = (PORTD & 0xF0) |  (c & 0x0F);
	LCD_STROBE;
	DelayUs(40);
}


/*	Clear and home the LCD  */
void
lcd_clear(void)
{
	LCD_RS = 0;
	lcd_write(0x01);
	DelayMs(2);
}

/* write a string of chars to the LCD */
void
lcd_puts(const char * s)
{
	LCD_RS = 1;	// write characters
	while(*s)
		lcd_write(*s++);
}

/* Go to the specified position */
void
lcd_goto(unsigned char pos)
{
	LCD_RS = 0;
	lcd_write(0x80+pos);
}


/* initialise the LCD - put into 4 bit mode */
void
lcd_init()
{
	LCD_RS = 0;	// write control bytes
	DelayMs(15);	// power on delay
	PORTD = 0x3;	// attention!
	LCD_STROBE;
	DelayUs(250);
	LCD_STROBE;
	DelayMs(5);
	LCD_STROBE;
	DelayMs(5);
	PORTD = 0x2;	// set 4 bit mode
	LCD_STROBE;
	DelayUs(40);
	lcd_write(0x28);	// 4 bit, 2 line , 5x7 font
	lcd_write(0x08);	// display off
	lcd_write(0x0F);	// display on, blink curson on
	lcd_write(0x06);	// entry mode
}

int main ()
{
// declaration of the variable for the main fuction
// unsigned char tempc;
   int analog_value0;
   int analog_value1;
   int analog_value2;
   int analog_value3;
   OPTION=0x00;
   GIE=0;
   DelayMs(100);
	  
// calling the initialization function.
   initialize_IO_ports();  // initialize IO ports
   initialize_ADC();       // initialize AD convertor
   lcd_init();             // initialize LCD
   lcd_clear();
   DelayMs(100);
   lcd_goto(40);
   
   while(1)
   {if(RB0==1)