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digitalfreak
Joined: 16 Feb 2005
Posts: 25
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| PIC 16F876 Resetting... |
 Posted: Wed Feb 15, 2006 1:13 pm |
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The PIC is resetting randomly...whats going on...??
I have a Push button for RESET PIC
Observation:
If I remove the RESET to MCLR the PIC works fine....add back in it works, but have some random resets?
checked the push button, I think it is good....
I need th RESET button!.
Do you think it is the noise? or adding a cap (something like .1uF) bet Vcc and Vdd will help...?
thanks. |
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Humberto
Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata
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| Posted: Wed Feb 15, 2006 2:08 pm |
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| Quote: |
Do you think it is the noise? or adding a cap (something like .1uF) bet Vcc and Vdd will help...?
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A ceramic capacitor between Vcc and Vdd is a must, no matter if it reset randomly or not.
Assuming you have a hardware problem in the reset line, the following are contributors to generate random reset:
- A high resistance value used as pull up.
- If wired to a pushbutton, long non shielded nor twisted cables.
- Defective switch/contact/connector. You can test this hitting the parts with some "light hammer"
- If an IC socket is used, low/poor contact pressure, dirty pins.
Humberto |
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digitalfreak
Joined: 16 Feb 2005
Posts: 25
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| Posted: Wed Feb 15, 2006 3:51 pm |
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thanks Humberto
added .1uF cap bet Vdd and Vcc - decreased the random resetting action a lot....
pull up is 5.1K
push button is OK and
iam using IC sockets, pins look fine though..
I still sometimes see (very rare though, not as frequent as before) random resets.
is there anything else i can try....
thanks.
| Humberto wrote: | | Quote: |
Do you think it is the noise? or adding a cap (something like .1uF) bet Vcc and Vdd will help...?
|
A ceramic capacitor between Vcc and Vdd is a must, no matter if it reset randomly or not.
Assuming you have a hardware problem in the reset line, the following are contributors to generate random reset:
- A high resistance value used as pull up.
- If wired to a pushbutton, long non shielded nor twisted cables.
- Defective switch/contact/connector. You can test this hitting the parts with some "light hammer"
- If an IC socket is used, low/poor contact pressure, dirty pins.
Humberto |
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