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Persistent Protection Scheme for Hybrid Sectors of Cypress flash devices – KBA232295

Persistent Protection Scheme for Hybrid Sectors of Cypress flash devices – KBA232295

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Persistent Protection Scheme for Hybrid Sectors of Cypress flash devices – KBA232295

Japanese Translation: サイプレスフラッシュ製品のハイブリッドセクターにおける永続的保護機構—KBA232295-Community translation (JA)

Author: ApurvaS_36           Version: **

Question:
For Hybrid Sector architecture in Cypress Flash, is there one PPB bit for each 4-KB Sector or is there a single PPB bit for all the 4-KB Sectors combined?

Answer:
There is a separate PPB bit for each 4-KB sector when hybrid sector architecture is configured in Cypress flash devices.

For example, the sector address map for S25FS512S (bottom 4-KB sector) device is shown below (see the datasheet).

Image.png

 

SA0 – SA7

Eight 4-KB sectors that should use a parameter 4-KB sector erase command (P4E, 4P4E)

SA8

224-KB sector that should use a sector erase command (SE, 4SE)

SA9 – SA263

256-KB sector that should use a sector erase command (SE, 4SE)

 

When the flash device is configured with hybrid sector architecture, each 4-KB sector and 224-KB sector can be protected or unprotected by individual PPB bits. The corresponding PPB bit is decided by the sector address. When the flash device is configured at uniform sector architecture, the eight 4-KB sectors and one 224-KB sector are combined as one 256-KB sector. One single PPB bit takes the control on the entire combined 256-KB sector.

You should set the required sector architecture first, before performing any other operation on the flash including sector protection. The following application note AN98551 - Advanced Sector Protection (ASP) in Cypress Quad SPI, Octal SPI, and HyperFlash Device Fam...

can be referred to learn about sector protection techniques in Cypress flash devices.

 

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