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Does the logic inside flash memory devices require a power down after each WRITE operation?

I was confused when reading the datasheet of the Micron Serial NOR Flash Memory.
There is "To avoid data corruption and inadvertent WRITE operations during power-up, a poweron reset circuit is included... ".

After WRITE operations (program or erase sector) to the Micron Serial NOR Flash Memory, it does not respond to any instruction during power-up except READ STATUS REGISTER, I have reset the circuit and the device remains in lock mode. I have to power down the chip to get correct values (previously written) back from the EPCQL.

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closed as unclear what you're asking by brhans, pipe, Dwayne Reid, RoyC, Voltage Spike Jan 22 at 17:06

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    \$\begingroup\$ Although the question as written is clear, it's not clear (at all) why you might think that a flash memory device would need to be powered down after each write. As such, this comes across as an X-Y problem and it's therefore not clear what you really want to know. Please edit your question to clarify. \$\endgroup\$ – brhans Jan 21 at 15:05
  • \$\begingroup\$ Thank you for your reply! I'm improving my change to get answers :) I was confused when reading the datasheet of the Micron Serial NOR Flash Memory. There is "To avoid data corruption and inadvertent WRITE operations during power-up, a poweron reset circuit is included... " when I need to erase sector or write to memory, here lies my problem; I can run nothing on board until repower the chip. After write operations, the device does not respond to any instruction and ignores all commands except READ STATUS REGISTER. \$\endgroup\$ – Chloé Russell Jan 22 at 8:10
  • \$\begingroup\$ What is the specific device you are using? Note that the power on reset is unlikely to be part of your problem. \$\endgroup\$ – Peter Smith Jan 22 at 12:47
  • \$\begingroup\$ Have you taken into account what the datasheet tells you, "You must execute the write enable operation before the write bytes operation." and "You must erase all the memory bytes of EPCQ-L devices before you implement the write bytes operation"? \$\endgroup\$ – pjc50 Jan 22 at 13:04
  • \$\begingroup\$ Your program needs to wait until the status register indicates the write is complete. \$\endgroup\$ – Chris Stratton Jan 22 at 13:23
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No, the logic in a Flash memory device does not need to be powered down between write cycles.

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  • \$\begingroup\$ I have noticed that after WRITE operations (program or erase sector), the device does not respond to any instruction, I have reset the circuit but it remains in lock mode during power-up, and I have to repower the chip to get correct values (previously written) back from the EPCQL. \$\endgroup\$ – Chloé Russell Jan 22 at 9:37
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Flash memory is essentially a switch and a capacitor. To write to a cell, you put a 1 or a 0 (high or low voltage) and then turn the transistor on. The capacitor then matches the voltage that was applied to it during the write cycle. Keep in mind that the charge on the capacitor slowly drains out and will eventually need to be refreshed.

So if by power down you mean disconnect the switch then yes. But the rest of the circuit is always powered up.

enter image description here Source: http://www.intersil.com/content/dam/Intersil/documents/an15/an1533.pdf

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  • \$\begingroup\$ Thank you for your reply :) After WRITE operations (program or erase sector) to the Micron Serial NOR Flash Memory, I have reset the circuit and the device remains in lock mode, it does not respond to any instruction during power-up except READ STATUS REGISTER. I need to reset (power down then power up) the chip to get the data (previously written) back from my EPCQL. I think that a system reset does not refresh the capacitor, I'm wondering if it is a normal behave of Flash memories or am I missing something.. \$\endgroup\$ – Chloé Russell Jan 22 at 15:26

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