Damage to memory cell due to unexpected reset

[NaMo_1534561]

顧客が作成したフラッシュ書替えプログラムにて

セクタの消去動作中に（意図せず）ハードウェアリセットがかかり、

リセット復帰後、改めてセクタ消去＋書込みを実行したところ実行時間が延びました。

（実測値で644ms-->792ms）

[質問1]上記実行時間が延びる要因として考えられることは何でしょうか？

[質問2]消去動作中にリセットがかかる様な状態が繰り返されると、フラッシュが

ダメージを受けその後の書き込み時間が徐々に延びて悪化していくのでしょうか？

[AlbertB_56]

Hello Morimoto-san,

Please provide the complete Ordering Part Number (OPN) of the Cypress FLASH memory device.

The Hardware RESET can be initiated at anytime during the execution of any embedded operation.

The increased time of ~150mS for sector erase and second programming, may be due to the pre-programming

sub-routine which occurs during the sector erase operation.  The sector selected for erase is pre-programmed

to all ZERO's, then erase back to ONE's.  The pre-programming sub-routine cannot be accessed by the user.

Therefore, the user cannot make any edits or changes to the pre-programming sub-routine.

However, as mentioned earlier, please provide the complete Ordering Part Number (OPN) of the the FLASH

memory device.

Thank you in advance...

Best Regards,

Albert

Cypress Semiconductor  

__________________________________________________________________________________________

ENGLISH TRANSLATION :

   With flash rewriting program created by customer
   A hardware reset is applied (unintentionally) during the sector erase operation,
   Execution of sector erase + write a second time after returning to reset, the execution time has been extended.
   (644 ms -> 792 ms as measured values)
   [Question 1] What are the possible reasons for extending the execution time?
   [Question 2] When the state where resetting occurs during the erase operation is repeated, the flash
   Will it get damaged and the subsequent writing time gradually increases and worsens?

__________________________________________________________________________________________

[NaMo_1534561]

Hello Albert-san,

the Ordering Part Number is S29GL128S90TFI020.

Best Regards,

Naoaki Morimoto

[AlbertB_56 · Accepted solution]

Hello Morimoto-san,

The sector erase time for a 128 KB sector is typically 275ms.  The effective 128KB Sector Programming time (using full 512-byte buffer)

is 108mS.  Therefore, Sector Erase time + Sector Program time equals 383mS.

The maximum Sector Erase time for 128KB sector is 1,100mS, and the effective 128KB Sector Programming time (using full 512-byte buffer)

is 192mS, then the Sector Erase time + Sector Program time equals 1,292mS,  Therefore a combined sector erase and program (write) os

792mS is well below and within limits of the maximum combined time of 1,292mS.

No damage to the FLASH will occur during H/W RESET.  However, sector erase time and programming time may increase over time,

if sector or chip erase and re-programming occurs frequently

Hope this helps...

Best regards,

Albert

Cypress Applications Support