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Nor Flash

Anonymous
Not applicable

Hello,

This problem happened occasionally. Please help.

Maker name: Cypress

Model: S25FL128SAGMF (Flash Memory)

After executed BulkErase, the EraseError bit in SR1 register has set to 1 and the erase action cannot be completed,

(It happened like 1 in 1000 unit)

When not execute the erase action, the register values are

SR1         0x05       0x00

SR2         0x07       0x00

CR1        0x35       0x00

The power voltage is 3.3V.

Any reason that caused this problem ?

Thanks in advance,

Sunny

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12 Replies
Anonymous
Not applicable

Hi,

I'm still having this problem and cannot be solve. I would greatly appreciated if anyone could provide hints or help. Any additional info needed, please let me know.

Thanks,

Sunny

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Anonymous
Not applicable

Hi,

Usually if the sector being erased is locked, the bit may be raised.

Also, if the sector is approaching end of life, the bit may be raised.

When the bit is raised, although the contents of the sector appear to be erased but we actually don't know the integrity of each cells.

If the E_ERR bit is raised, the user has to issue CLSR to clear the status bit before issuing any other commands.

Also, could you let us know what Bulk Erase command you use?

Thanks,

Nada

Anonymous
Not applicable

Hi,

Sorry for my late reply.

The Bulk Erase command was 0xc7.

Also tried with sector erase, the same problem happened and the E_ERR bit raised. The erase command cannot be completed. After cleared the status bit, write command works fine.

So erase the flash memory is not possible. Please help.

Thanks,

Sunny

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ZhiF_31
Employee

Hi Sunny,

You may want to check if any of the sectors in the device is protected.

If the SR=0, that means BP bits are 0, i.e. sector not protected by BP bits.

You can loop all sectors to check DYB bits. DYB Read command is E0h. If any of the sector returns non-FFh, that means the sector is protected.

You should also loop all sectors to check PPB bits. PPB Read command is E2h. If any of the sector returns non-FFh, that means the sector is protected.

Please let us know the results of the DYB and PPB bits.

Thanks,

Zhi

Anonymous
Not applicable

Hi Zhi,

Thank you for your reply.

Both DYB and PPB bits are FFh. Still got no clue why can't erase the flash memory.

Thanks,

Sunny

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ZhiF_31
Employee

Hi Sunny,

If you just erase one sector, is the operation successful?

You mentioned Bulk Erase failed ratio is like 1 in 1000. Does the failed unit always fail to be erased? If you erase sectors one by one on that unit, what did you see? Does it always fail on fixed sectors?

Thanks,

Zhi

Anonymous
Not applicable

Hi Zhi,

Thank you for your follow up.

Erase one sector also tried. It succeed without error, but the sector remains the same, it didn't get erase.

> You mentioned Bulk Erase failed ratio is like 1 in 1000. Does the failed unit always fail to be erased?

Yes, it always fail in that unit.

> If you erase sectors one by one on that unit, what did you see?

Nothing. No error and no erase happen.

> Does it always fail on fixed sectors?

Tried with all the 64K fixed sector size with some very small sizes at the end, and the result was the same.

Thanks,

Sunny

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ZhiF_31
Employee

Hi Sunny,

You said the erase returns no error but did not actually erase. Were you reading back the sector and there are still data in it? Did you wait enough time or poll for the completion of the erase before you read the sector?

Does the same code work for other devices but not this particular one? If so, you may want to contact Cypress FAE to return this failed unit for analysis.

Thanks,

Zhi

Anonymous
Not applicable

Hi Zhi,

Thank you for your support.

Yes, with the same code work for all other devices but not this one. We will try to contact the local Cypress FAE in Osaka and see how they can handle this.

Thanks,

Sunny

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Anonymous
Not applicable

Hi Zhi,

Just wonder where can I find a list Cypress FAE either in Japan or other countries ? Greatly appreciated your help.

Thanks,

Sunny

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TakahiroK_16
Employee

Hi Sunny,

Could you contact local distributor who sells Cypress devices to you? They will help creating failure analysis request.

Best Regards,

Takahiro

Anonymous
Not applicable

Hi Takahiro,

We bought them from Mouser <https://www.mouser.jp/> and they don't seem to handle that. The jp sales office from Cypress also asked us to contact the reseller, but again Mouser doesn't do that.

Thanks,

Sunny

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