Pullup ou pulldown on SCK signal of S25FL256S ?

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
ErFo_3086866
Level 1
Level 1
0 Likes
1 Solution
SudheeshK
Moderator
Moderator
Moderator
250 sign-ins First question asked 750 replies posted

Hello,

Pull up resistors are not required on the SPI lines to avoid accidental write operations to our serial NOR flash devices. But, you can connect a pull up on CS# signal for proper initialization of the device during power up. Please see more details in our knowledge base article available at: Power Up/Down Requirement in Serial NOR Flash Devices – KBA220676 .

Cypress serial NOR flash devices will perform a program/ erase operation only if it receives the correct sequence of commands. Please refer the datasheet (https://www.cypress.com/file/448601/download ) for details about command sequence for different operations.

e.g. Command sequence for program operation

  1. CS# LOW
  2. Send WREN command (0x06)
  3. CS# HIGH
  4. CS# LOW
  5. Send PROGRAM command (0x02)
  6. Send Address
  7. Send data
  8. CS# HIGH

Flash will ignore the operation, if proper command sequence is not received. Please ensure that you are selecting the flash device (CS# LOW) only when there is a valid operation to perform (read, program, erase etc).

You can also enable block protection feature of our NOR flash device to prevent writes to flash device. Please refer datasheet for more details.

I hope the above information answers your query. Please feel free to ask if you have more queries.

Thanks and Regards,

Sudheesh

View solution in original post

0 Likes
2 Replies
SudheeshK
Moderator
Moderator
Moderator
250 sign-ins First question asked 750 replies posted

Hello,

Pull up resistors are not required on the SPI lines to avoid accidental write operations to our serial NOR flash devices. But, you can connect a pull up on CS# signal for proper initialization of the device during power up. Please see more details in our knowledge base article available at: Power Up/Down Requirement in Serial NOR Flash Devices – KBA220676 .

Cypress serial NOR flash devices will perform a program/ erase operation only if it receives the correct sequence of commands. Please refer the datasheet (https://www.cypress.com/file/448601/download ) for details about command sequence for different operations.

e.g. Command sequence for program operation

  1. CS# LOW
  2. Send WREN command (0x06)
  3. CS# HIGH
  4. CS# LOW
  5. Send PROGRAM command (0x02)
  6. Send Address
  7. Send data
  8. CS# HIGH

Flash will ignore the operation, if proper command sequence is not received. Please ensure that you are selecting the flash device (CS# LOW) only when there is a valid operation to perform (read, program, erase etc).

You can also enable block protection feature of our NOR flash device to prevent writes to flash device. Please refer datasheet for more details.

I hope the above information answers your query. Please feel free to ask if you have more queries.

Thanks and Regards,

Sudheesh

0 Likes

Thank you for your prompt response !

Best Regards,

Eric

0 Likes