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Original question:

TUSB9261: Can be used without external EEPROM?

TUSB9261: Can I write protect the flash to prevent reprogramming?

Tim Anderson59
Prodigy 230 points
Part Number: TUSB9261

Hi, the TUSB9261 is programming as expected and appears to be working fine. However I would like to lock down the Ic so that it cannot be reprogrammed in the field. Since there is some data in the IC, and some in the flash, will write protecting the flash work, or cause issues? Is there any other way to lock down the TUS9261 to prevent reprogramming?

Thanks

Tim

  • 0
    TI__Expert 4325 points
    Hi Tim,
    There is no way to "lock" programming through our SW as the flash burner tool automatically sends SW commands to unlock programming. You would need to remove the pull-up resistor on the SPI flash WP pin to protect it. That should not cause any issue with normal operation.
    Regards,
    Brian
  • 0 in reply to Brian Quach
    Prodigy 230 points
    I'm currently using a AT25DN512C SPI Flash IC. This IC requires that specific bits be written to the "Status Register" before the WP pin will block writing. Is it possible to send a write command through the TUSB9261 to the AT25DN512C? Or do I need to program the flash directly?

    Would programming the flash through SPI while connected to the TUSB9261 cause any issues? My goal would be to program the flash after assembly.

    Thanks

    Tim
  • 0 in reply to Tim Anderson59
    TI__Expert 4325 points
    Hi Tim,
    You cannot set that status register directly through the TUSB9261. Programming the SPI flash externally while the TUSB9261 is attached would be problematic because you would have multiple SPI masters and the SCLK and MOSI pins would be outputs. I would preprogram the flash prior to soldering on the board.

    Regards,
    Brian