Final Project Graduation

[calmo_]

Hello,

I'm doing my final project graduation and using a PIC to make a clock with alarm. I'm gonna use too a 4MHZ crystal and an 16x2 LCD. The compiler is mikroC and I need a little help for how to read the oscillation of the crystal and use this in my code. If you have any codes example with comments and circuits with crystals in mikroC I will really appreciate that.

Thanks!

 

[horace1]

which PIC are you planning to use? have a look at the Microchip code examples
**broken link removed**

 

[calmo_]

It's a 16F876A. I'm taking a look in your link, very good examples, really going to help.

 

[thunderboympm]

which is the real time clock you are using? Lcd specification?

 

[mehtadhaval]

I'm doing my final project graduation and using a PIC to make a clock with alarm. I'm gonna use too a 4MHZ crystal and an 16x2 LCD. The compiler is mikroC and I need a little help for how to read the oscillation of the crystal and use this in my code.

If you're making a clock, then you should be using a RTC (Real Time Clock).

 

[calmo_]

In Proteus I'm using LCD LM020L. I would prefer not to use a RTC, cause I don't need date, the system will be used once a day. I was planning just to use tmr0 with interruption, and there is where my problem starts. I can't figure out how to configure the tmr0 and use interruptions.

 

[horace1]

here is a bit of code useing timer 0 of a to interrupt every 10mSeconds using a PIC16F917 on a Microchip PICDEM Mechatronics board

static volatile int tenMillSecCounter2=0;       // incremented every 10mSec - used for delays

// Timer 0 is programmed to interrupt every 10mSeconds
//  T0 clock is FOSC/4 = 200000
//  with 256 prescaler decrements 2000000/256 times / second
//  to get an interrupt every T mSec the calculation for TMR0 overflow from 0xFF to 0 is
//    count = 255 - T * 2000/256
//    i.e. for 10mSec counter is
#define tenMillSec 177
static void interrupt isr(void)
{
    if (T0IF)                           // A TMR0 interupt occurred
    {
        TMR0=tenMillSec;                // increment counters every 10 mSec
        tenMillSecCounter2++;
     }
    T0IF=0;                             // clear TMR0 interrupt flag
}

// delay for count tenths of a second
void tenthsSecondDelay(int count)
{
    tenMillSecCounter2=0;                         // zero counter
    while( tenMillSecCounter2  < (count*10)) ;    // wait
}
        
// delay for count seconds
void secondDelay(int count)
{
    tenMillSecCounter2=0;                         // zero counter
    while( tenMillSecCounter2  < (count*100)) ;   // wait
}
        
// initalise clock, set port A for digital input, set up timer 0, etc
void systemInitialise(void)
{
        OSCCON=0x70;             // Fosc use oscillator 8MHz
        ANSEL=0;                 // set digital inputs
        // PORTB PULL-UP DISABLED, TMR0 Timer mode Clock Source Select bit FOSC/4,  
        // Prescaler is assigned to the Timer0 module & TMR0 RATE 1:256
        OPTION=0x87;             
        TMR0=tenMillSec;         // initialise timer 0 counter
        T0IE = 1;                // enable interrupt on TMR0 overflow from 0xFF to 0
        GIE = 1;                 // Global interrupt enable
 }

 

[arbj]

use a 32 Khz watch crystal. Its more accurate than the timers in the device.