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Digital Thermometer Coding Help!!!!!

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jhunt315

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I found some code online to set up a digital thermometer. I am using an LM34 and PIC16F917 hooked up to a seven segment display where it will read the temperature and display it on the seven segment display. I was wondering if anyone can tell me if i need the 20MHz crystal oscillator at all (or if i can do it without it) and in what line (if any) does the temperature actually get read?

Code:
#include <htc.h>

#define _XTAL_FREQ 20000000UL

typedef unsigned char UINT8;
typedef signed char INT8;
typedef unsigned int UINT16;
typedef signed int INT16;

//Connection of Seven segment display

#define SEVEN_SEGMENT_LAT PORTB
#define SEVEN_SEGMENT_TRIS TRISB

#define MUX_PORT PORTB
#define MUX_START_POS 1


#define MUX_DISP_COUNT 4

//Global Varriable
UINT8 DisplayArray[MUX_DISP_COUNT];//Holds 'data' for each disp

void SevenSegmentWrite(UINT16 n)
{
/*

This function breaks apart a given integer into separete digits
and writes them to the display array i.e. digits[]
*/

UINT8 i=0;
UINT8 j;

while(n)
{
DisplayArray=n%10;
i++;

if(i==MUX_DISP_COUNT)
break;

n=n/10;
}

//Fill Unused area with 0
for(j=i;j<MUX_DISP_COUNT;j++) DisplayArray[j]=0;
}

void WriteSegment(UINT8 num)
{
switch (num)
{
case 0:
//-GFEDCBA

SEVEN_SEGMENT_LAT = 0B01000000;
break;

case 1:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B01111001;
break;

case 2:
//-GFEDCBA

SEVEN_SEGMENT_LAT = 0B00100100;
break;

case 3:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B00110000;
break;

case 4:
//-GFEDCBA

SEVEN_SEGMENT_LAT = 0B00011001;
break;

case 5:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B00010010;
break;

case 6:
//-GFEDCBA

SEVEN_SEGMENT_LAT = 0B00000010;
break;

case 7:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B01111000;
break;

case 8:
//-GFEDCBA

SEVEN_SEGMENT_LAT = 0B00000000;
break;

case 9:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B00010000;
break;

}

}


void Wait()
{
UINT8 i;
for(i=0;i<1;i++)
__delay_ms(10);
}
void main()
{
//Set Up I/O Ports

TRISB0=0;
SEVEN_SEGMENT_TRIS = 0B10000000;//Disp is connect from 0-6 last bit 7 is unused

//MUX select lines
TRISB = 0B11100001;

//Init TIMER0

T0CS=0; //Timer Clock source is intruction clock that is 5MHz
PSA=0; //Prescaler is assigned to TIMER0
PS2=1;
PS1=1;
PS0=0; //Prescaler = FCPU/128

TMR0=1; //Enable Timer0 Interrupt
PEIE=1; //Enable Peripheral Interrup

//Enable Interrupts Globally
ei();

while(1)
{
for (UINT16 i=0;i<10000;i++)
{
SevenSegmentWrite(i);
Wait();
}
}



}




//Our Interrupt Service Routine
void interrupt ISR()
{
if(T0IE && T0IF)
{
//TIMER0 Overflow Interrupt
//First Clear the INT flag
T0IF=0;

//Value of "static varriable" is retained between calls
static int i;

//Switch On Display Pointed by 'i'
MUX_PORT = (~(1<<(i+MUX_START_POS)));

//Latch digit on it

WriteSegment(DisplayArray);

//On each time out select next display
i++;

//If on last display then goto first
if(i==MUX_DISP_COUNT)
i=0;
}
}

Also the code is attached. View attachment Code.txt
 

jhunt315

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I do not think there is anything in this code for basically reading an analog signal, which is reading the thermometer. Can anyone help me add that code into the code above to complete my digital thermometer?
 

jhunt315

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How would i include a thermometer/ what do i have to do to turn this into a digital thermometer?
 

MARWEN007

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is a look to this site you need to translate the page into English is your happiness ;)
‚o‚h‚b
 

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