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kkostienko
Joined: 18 Oct 2005
Posts: 3
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| Why my pic18f452 is restarting ? |
 Posted: Mon Feb 06, 2006 12:25 pm |
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Hi,
I have little problem with my PIC18F452. I do not why he is going down. It is randomly, after few second or after one minute. I have heard that use capacitor 100 uF between +5 and GND near the PIC, to decouple any noise that could reset the PIC, can help. I am going to check it tomorrow, but maybe you have other idea?
Thanks
_________________
With best regards
Kostienko
MSN kostienk@coventry.ac.uk |
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kkostienko
Joined: 18 Oct 2005
Posts: 3
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| Posted: Mon Feb 06, 2006 12:32 pm |
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I have forgoten to say that i chacked few PIC18, one which I have got today(so for sure this is not coused by the PIC18F452).
_________________
With best regards
Kostienko
MSN kostienk@coventry.ac.uk |
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jecottrell
Joined: 16 Jan 2005
Posts: 559
Location: Tucson, AZ
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| Posted: Mon Feb 06, 2006 12:57 pm |
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I had similar problems when PUT was enabled by accident. Ensure you have NOPUT in your fuses and see if that fixes it....
Good Luck,
John |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Feb 06, 2006 1:17 pm |
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Possible reasons for apparently "random" resets:
1. The Watchdog timer is enabled, but is not being reset frequently
enough, or in the correct places within the program.
2. The #fuses are set for LVP mode, instead of NOLVP, and the
PGM pin has been left floating.
3. The code is allowed to fall off the end of main(), so that the PIC
goes to sleep. The PIC then wakes up at random times, due to
an interrupt, and starts executing garbage code. It may eventually
jump to address 0 and start executing properly again, or maybe not. |
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rnielsen
Joined: 23 Sep 2003
Posts: 852
Location: Utah
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| Posted: Mon Feb 06, 2006 2:50 pm |
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I have found that it very important to place a filter cap (VCC to GND) near the PIC. A .1uf cap should be enough, provided that your power supply is also sufficiently filtered. Stray noise Can cause problems with any processor.
Ronald |
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jecottrell
Joined: 16 Jan 2005
Posts: 559
Location: Tucson, AZ
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| Posted: Mon Feb 06, 2006 3:46 pm |
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| I gooned that one up. Remove all references to PUT and change it to BROWNOUT! Use NOBROWNOUT in your fuses and see if that helps.... |
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kkostienko
Joined: 18 Oct 2005
Posts: 3
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| Posted: Mon Feb 06, 2006 4:52 pm |
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Thank you,
I will check all your guides tomorrow and will give then reply post.
See you soon
_________________
With best regards
Kostienko
MSN kostienk@coventry.ac.uk |
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kkostienko
Joined: 18 Oct 2005
Posts: 3
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| Posted: Fri Feb 10, 2006 10:43 am |
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Thanks,
I have used the 100 nF Cap and now works great 
_________________
With best regards
Kostienko
MSN kostienk@coventry.ac.uk |
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