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jaikumar
Joined: 15 Dec 2006
Posts: 109
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| 16F887 watchdog timer problem |
 Posted: Mon Aug 19, 2013 6:26 am |
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Hi All,
Controller: 16F887
CCS version: 4.140
Having trouble with the code below, Watchdog timer setting is a problem,
watchdog timer works only if i just use fuse WDT and no other setting in the code.
If i use the code setup_wdt(WDT_2304MS); watchdog timer does not work.
Please can somebody help.
Thanks and Regards,
jai.
MAIN.H
| Code: |
#include <16F887.h>
#device ADC=16
#FUSES INTRC_IO
#FUSES WDT //Watch Dog Timer
#FUSES BROWNOUT //No brownout reset
#FUSES BORV40
#FUSES NOLVP //No low voltage prgming, B3(PIC16) or B5(PIC18) used for I/O
#use delay(internal=4000000, restart_wdt)
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MAIN.C
| Code: |
void main()
{
int8 rCause;
rCause = 0;
tsec = 0;
tmin = 0;
thrs = 0;
sTick = 0;
setup_oscillator(OSC_4MHZ);
//setup_wdt(WDT_2304MS); //ONLY WORKS IF COMMENTED OUT
setup_timer_1(T1_EXTERNAL|T1_CLK_OUT|T1_DIV_BY_1);
set_timer2(16);
setup_timer_2 (T2_DIV_BY_4, 1, 1);
rCause = restart_cause();
enable_interrupts(INT_TIMER2);
enable_interrupts(INT_TIMER1);
enable_interrupts(GLOBAL);
while(TRUE)
{
if (input(PIN_D0) == 1) {restart_wdt();}
if (tmin == 1) {tmin = 0; output_toggle(PIN_D1);}
if (rCause == WDT_TIMEOUT) {output_high(PIN_D3);}
//TODO: User Code
}
}
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jaikumar
Joined: 15 Dec 2006
Posts: 109
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| Posted: Mon Aug 19, 2013 6:46 am |
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Hi All,
It works only when you use setup_wdt(WDT_TIMES_64);
with the constants below:
#define WDT_TIMES_1 0x900 // Default
#define WDT_TIMES_2 0xB00
#define WDT_TIMES_4 0xD00
#define WDT_TIMES_8 0xF00
#define WDT_TIMES_16 0x1100
#define WDT_TIMES_32 0x1300
#define WDT_TIMES_64 0x1500
#define WDT_TIMES_128 0x1700
Can some one please explain.
regards,
Jai. |
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ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
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| Posted: Mon Aug 19, 2013 6:55 am |
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From the header file: | Code: | // Watch Dog Timer Functions: SETUP_WDT() or SETUP_COUNTERS() (see above)
// RESTART_WDT()
// WDT base is 18ms
//
#define WDT_18MS 8
#define WDT_36MS 9
#define WDT_72MS 10
#define WDT_144MS 11
#define WDT_288MS 12
#define WDT_576MS 13
#define WDT_1152MS 14
#define WDT_2304MS 15
// One of the following may be OR'ed in with the above:
#define WDT_ON 0x4000
#define WDT_OFF 0 |
so, your line for configuring the watchdog | Code: | | setup_wdt(WDT_2304MS); |
is the same as: | Code: | | setup_wdt(WDT_2304MS | WDT_OFF); |
Makes sense that the WD isn't working then.
Not tested, but try: | Code: | | setup_wdt(WDT_2304MS | WDT_ON); |
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jaikumar
Joined: 15 Dec 2006
Posts: 109
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| Posted: Mon Aug 19, 2013 7:02 am |
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Thanks for the help.
But that does not work.
Does not work - setup_wdt(WDT_2304MS | WDT_ON);
Works - setup_wdt(WDT_ON | WDT_TIMES_128);
regards,
Jai. |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19552
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| Posted: Mon Aug 19, 2013 7:54 am |
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Get rid of your interrupt code.
You are potentially interrupting every eight instructions. The effect on overall behaviour will make it difficult to find out what is really happening.
You are setting timer2, to clock off the (FOSC/4)/4. One clock every four instructions, and then setting it to reset on a count of '1', and interrupt every time.
Start with just the watchdog code.
I've just tested:
setup_wdt(WDT_2304MS | WDT_ON);
and it is correctly watch-dogging, with your compiler version, and chip.
I'd suspect something like you have a delay in the interrupt handler, and this is preventing the watchdog from triggering with most settings....
Best Wishes |
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