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| Author |
Message |
Christophe
Joined: 10 May 2005
Posts: 323
Location: Belgium
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| counting hours |
 Posted: Thu Jun 30, 2005 6:39 am |
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Hi,
every time I switch the device off, I want the timer1 to start counting hours, after 24 hours, the PIC should do something and go to sleep.
Unfortunately, my PIC counts wrong:
| Code: | //************************** Timer1 interrupt ********************************//
//Timer1 wordt gestart als de NS uit staat
#int_timer1
Timer1_isr()
{
if(int_count++ == 2)
{
++secs;
if(secs==10)
{
putc('E');
//mins=mins+1;
secs=0;
setup_timer_1(T1_DISABLED);
}
// if(mins==60)
// {
// hrs=hrs+1;
// mins=0;
//}
/* if(hrs == 2)
{
hrs=0;
}
*/
int_count = 0;
}
Set_Timer1 ( 0x0BDB);
}// TIMER1 |
| Code: | //************************** EXTERNAL interrupt ******************************//
//Interrupt als de AAN/UIT schakelaar wordt bewogen
#INT_EXT
void ext_isr()
{
int8 i;
for (i = 0; i < 30; i++) // Debounce
{
delay_us(999);
}
if (input(AAN_UIT))
{
E3_SLEEP = FALSE;
setup_timer_1(T1_DISABLED);
sleep_mode = FALSE;
}
else
{
E3_SLEEP = TRUE;
setup_timer_1( T1_INTERNAL| T1_DIV_BY_8 );
Set_timer1 ( 0x0BDB); // Start de Timer1 vanaf
}
if (E3_SLEEP)
{
printf("%c%S%c",COMMANDO_BYTE, SLEEP_COMMANDO,0);
ext_int_edge(L_TO_H);
}
else
{
setup_uart(TRUE);
if (!sleep_mode)
printf("%c%S%c",COMMANDO_BYTE, WAKE_COMMANDO,0);
ext_int_edge(H_TO_L);
}
} |
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Neutone
Joined: 08 Sep 2003
Posts: 839
Location: Houston
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| Posted: Thu Jun 30, 2005 7:28 am |
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Think about how this works. You could do the same with timer 1.
| Code: |
/*********************************************
* Initialize RTC *
*********************************************/
void Initialize_RTC(void)
{ Ticker = XTAL_FREQUENCY;
setup_timer_2 ( T2_DIV_BY_4, 0xff, 4 ); // initialize 8 bit counter/timer 2 to interupt every 16384 clock cycles
enable_interrupts( INT_TIMER2 ); // Start RTC
}
// Global Real Time Clock Information
#int_TIMER2 // Clock interrupt adjusted to occurs ~ 1ms
void TIMER2_isr() // -=Process Zero Drift Real Time Clock Information=-
{ tickmSec = 1; // set each MS very approximately
Ticker -= 16384; // Decrement ticker by clocks per interupt
if ( Ticker < 16384 ) // If second has expired
{ Ticker += XTAL_FREQUENCY; // Increment ticker by clocks per second
second++; // Increment number of seconds
tickSec = 1; // set each Second very accuratly
}
} |
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Christophe
Joined: 10 May 2005
Posts: 323
Location: Belgium
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| Posted: Thu Jun 30, 2005 7:35 am |
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well,
I could it with timer2; difference:
Timer2: interrupt every 16384 us (your example)
Timer1: interrupt every 50000 us (1/2 s)
What you think is most efficient?
In the meanwhile I found the bug.. thanks f|#C=n CCS:
the bug is this statement:
| Code: | Timer1_isr()
{
if(int_count++ == 2)
{ blabla;... } |
should be:
| Code: | Timer1_isr()
{
int_count++;
if(int_count == 2)
{ blabla;... } |
Don't ask me why, but it works now.. took me some hours :\ |
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Ttelmah
Guest
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| Posted: Thu Jun 30, 2005 7:55 am |
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The two statements are different.
In the 'new' one, you increment the value _before_ testing it.
The equivalent 'combined' statement, is:
| Code: |
Timer1_isr()
{
if(++int_count == 2)
{ blabla;... }
|
Note where the '++' is. Putting it in front of the variable, means 'increment, then take the value'.
However the syntax 'int_count++', means take the value, _then_ increment the variable.
This will give an extra 'count' in the interrupt routine, before the value is seen to be right.
Best Wishes |
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Christophe
Joined: 10 May 2005
Posts: 323
Location: Belgium
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| Posted: Thu Jun 30, 2005 8:39 am |
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Just tested that,
it's true, thanks again for the information |
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