 |
 |
| View previous topic :: View next topic |
| Author |
Message |
ben_r
Joined: 26 Mar 2004
Posts: 4
|
| Strange automatic reseting behavoir |
 Posted: Fri Apr 02, 2004 4:40 pm |
 |
|
Hi,
My PIC 18F2320 appears to be reseting automatically. The PIC will run for about 136.5 seconds then reset. The time was measured by implementing an interrupt routine which counts every 50ms and prints the tick count.
I have tried several PICs incase it was a fault with the chip.
The trimed down code is show below - nothing obvious seems wrong - however it still resets. The reset is observered by the "ready ?" prompt reapearing. If it is left for many minutes several ready prompts will appear - indicating it still resets when just waiting on the getc().
| Code: |
#include <18F2320.h>
#device ADC=10
#fuses INTRC,NOWDT,NOPROTECT,NOLVP,NOBROWNOUT
#use delay(clock=8000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
void main() {
setup_oscillator(OSC_8MHZ | OSC_INTRC) ;
delay_ms(100);
printf("Ready ?");
getc();
printf("Running...\r\n");
while(TRUE) {;}
}
|
The watchdog timer is turned off as is brownout detection - is there someting else that resets the PIC that im forgetting (theres no problems with stack overflow as it just sits in a loop)?
Thanks,
Ben  |
|
 |
Haplo
Joined: 06 Sep 2003
Posts: 659
Location: Sydney, Australia
|
|
| Posted: Fri Apr 02, 2004 5:13 pm |
|
|
Look in the .LST file at the code generated for your while(TRUE) {;} statement. Make sure it is actually implementing an endless loop, not getting derailed and executing every single instruction until the end of the memory and then warpping around which will make you think it is 'reseting'.
Or try using while(TRUE); instead. |
|
|
ben_r
Joined: 26 Mar 2004
Posts: 4
|
|
| Posted: Fri Apr 02, 2004 8:25 pm |
|
|
Ok - I seem to have made a little progess...
It seems that this is something to do with the watchdog timer not been disabled (the maximum WDT period is 131seconds - about the duration that i am observing). Enabling the WDT and restarting it within loop allows the program to keep running past the 130second limit - but there must be a way of disabling the WDT?
I have explicity disabled it via the fuses config - however it still seems to be triggering. The config fuses in the .lst file look ok:
| Code: |
/* .c */
#fuses INTRC_IO,NOWDT
/* .lst */
Configuration Fuses:
Word 1: C800 INTRC_IO FCMEN IESO
Word 2: 1E0F BROWNOUT NOWDT BORV20 NOPUT WDT32768
Word 3: 8300 CCP2C1 MCLR PBADEN
Word 4: 0085 STVREN NODEBUG LVP
Word 5: C00F NOCPD NOPROTECT NOCPB
Word 6: E00F NOWRT NOWRTD NOWRTB NOWRTC
Word 7: 400F NOEBTR NOEBTRB
|
Word 2 - It seems that a WDT32768 is applied, however the bit for the WDT (bit 0 in the high byte) is 0 so that shouldn't cause a problem...
What is strange is that if I explicity set a lower WDT, ie:
| Code: |
#fuses INTRC_IO,NOWDT,WDT1024
|
The expected behavoir would be a reset after 4 seconds (assuming that the compiler is not correctly disabling the WDT as observed) - however this still takes 130 or so seconds to reset.
This is all getting very strange - has anyone had success with running the 18F2320 with the WDT disabled? I had a quick look at the device file and the values all seemed correct...I even reinstalled incase I had a corrupt device file.
Any help would be much appreciated...
Thanks,
Ben |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
FAQ 
Search
Register
Profile 
Log in to check your private messages 
Log in
