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Fram_fr
Joined: 29 Oct 2008
Posts: 13
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| Pic 16F1823, timer and CCS: issue? |
 Posted: Mon Feb 28, 2011 11:31 am |
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Hi all,
i'm in progress to work on a small new design (real pcb) using a Pic 16F1823 with CCS 4.114.
Have an issue with delay_ms (does not work), so try to use timer1 to blink a pair of led.
1st issue: timer1 overflow is out of timing...
timer1 overflow every 500µs instead of 1ms, here are some parts of my code:
| Code: |
#fuses INTRC_IO,NOWDT,NOPUT,NOBROWNOUT,NOLVP
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| Code: |
#define TIMER_1_PRELOAD (65536 - 2000)
#int_timer1 // interrupt rate of 1 ms
void timer1_isr()
{
set_timer1(TIMER_1_PRELOAD);
// Decrement any timers that are running.
if(tempo_green_led>0)
tempo_green_led--;
if(tempo_red_led>0)
tempo_red_led--;
}
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| Code: |
//****************************************************************************//
// Initialize timer1
//****************************************************************************//
/* Setup timer 1
* On a 16 Mhz clock, this will trigger a timer1 interrupt every 1.0 ms
* to work properly, Timer1 must overflow every millisecond
* OverflowTime = 4 * (1/OscFrequency) * Prescale * Period
* Prescale = 2
* Period = TIMER_1_PRELOAD = 2000
* For 16 Mhz: .001 seconds = 4 * (1/16000000 seconds) * 2 * 2000
*/
//****************************************************************************//
setup_timer_1(T1_INTERNAL | RTCC_DIV_2);
set_timer1(TIMER_1_PRELOAD);
setup_oscillator(OSC_16MHZ);
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2nd issue: my leds are not blinking in the same time, but use the same timer1, use similare functions, the same schematic....i'm a bit lost...
Thank you for your help |
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Fram_fr
Joined: 29 Oct 2008
Posts: 13
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| Posted: Mon Feb 28, 2011 12:00 pm |
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just try something...change my values from unsigned INT8 and unsigned INT16 into signed INT8 and signed INT16 and the 2 leds blink together....  |
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Fram_fr
Joined: 29 Oct 2008
Posts: 13
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| Posted: Mon Feb 28, 2011 12:11 pm |
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Just find what's wrong with my timer.... 
have to change
| Code: | setup_timer_1(T1_INTERNAL | RTCC_DIV_2);
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with
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setup_timer_1(T1_INTERNAL | T1_DIV_BY_2);
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tejca
Joined: 16 Sep 2011
Posts: 2
Location: SLOVENIJA
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| Posted: Fri Sep 16, 2011 2:10 pm |
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a little old topic but still.
as far as I know is RTCC used in Timer0.
Take a look in manual for CCS.
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