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arunb
Joined: 08 Sep 2003 Posts: 492 Location: India
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What are the chances of a data corruption ?? |
Posted: Wed Nov 22, 2006 7:51 am |
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Hi,
If the +5V line is gradually reduced to zero , with the PIC actively writing to the internal EEPROM, will the data being written be corrupted ??
I have used POR, Brown out detect and Power up timer...
thanks
arunb |
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Humberto
Joined: 08 Sep 2003 Posts: 1215 Location: Buenos Aires, La Reina del Plata
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Posted: Wed Nov 22, 2006 8:32 am |
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Obvious reply is YES
Your question is very short and we doesn´t know details regarding your hardware, your code, etc:
- Whats the reason for the described situation ?
- Is this an unexpected situation ?
- Do you have the ability to detect power fail ?
- How many bytes are you trying to store in EEPROM while power is falling down ?
- Did you add some extra capacitance in the power supply to slow down the fall. ?
- Wich microcontroller are you using?
Humberto |
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Ttelmah Guest
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Posted: Wed Nov 22, 2006 8:50 am |
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Humberto has really covered it.
The 'key' though is that writes take a known time. There is a specified minimum operating voltage for the processor to operate. You talk about 'using brownout detect'. Is this _LVD_, or brownout reset?. The former will allow you to detect a supply voltage drop, and if you know the consumption of the circuit, and the size of the supply capacitor, you can then know how long you can keep operating. The latter resets the chip, and will itself interfere with a write...
Best Wishes |
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