2 Replies Latest reply on Mar 23, 2020 6:49 AM by ErFo_3086866

    Pullup ou pulldown on SCK signal of S25FL256S ?

    ErFo_3086866
        • 1. Re: Pullup ou pulldown on SCK signal of S25FL256S ?
          SudheeshK_26

          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

          • 2. Re: Pullup ou pulldown on SCK signal of S25FL256S ?
            ErFo_3086866

            Thank you for your prompt response !

             

            Best Regards,

            Eric