CFI Data to Set Proper Timeout Timer Value for Program and Erase Operations for Parallel NOR Flash - KBA226647

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Author: YongQ_16           Version: **

Translation - Japanese: 並列NORフラッシュのプログラムおよび消去操作に適切なタイムアウト時間の値を設定するCFIデータ - KBA226647 - Community Translated (JA)

Question:

What timeout timer value should I set for Program and Erase operations for Cypress Parallel NOR Flash?

Answer:

You can set the timeout timer value by either of the following:

• Using the Program and Erase maximum time specification stated in the device datasheet
• Calculating the maximum Program and Erase time using CFI data

All Cypress Parallel NOR Flash products are CFI compliant. The second option (using CFI data) is the best and the suggested approach. This approach makes the code portable while migrating to other CFI-compliant Parallel NOR devices.

Consider the following example. The parameter locations (Addresses) shown in the table are the same for all CFI-compliant flash devices. Data may not be the same.

Parameters highlighted in red are for Write Buffer Program. Data at Byte Address (0040h) indicates the typical timeout time for Write Buffer Program is 2^Nus. N is the data 0009h. The typical timeout time for Write Buffer Program is 2⁹us.

Data at byte address (0048h) indicates the maximum timeout time for Write Buffer Program is (2^N x typical timeout time). N is the data 0001h@85^oC, or 0002h@105^oC. The maximum timeout time for Write Buffer Program is (2² x 2⁹) µs. If the device temperature range is up to 85^oC, then the data @85^oC can be used for the maximum timeout time calculation.

Timeout timer value for Write Buffer Program should be set as the maximum timeout time, which is (2² x 2⁹) µs in this example.

Parameters highlighted in blue are for sector erase. Data at byte address (0042h) indicates the typical timeout time for sector erase. Data at byte address (004Ah) indicates the maximum timeout time for sector erase is (2^N x Typical timeout time). Same calculation, the timeout timer value for sector erase is (2² x 2¹⁰) ms.

The same calculation also applies to single word program and chip erase.

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