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TUSB9261 Write Blocking

Christopher Williams79
Prodigy 140 points
Other Parts Discussed in Thread: TUSB8041, TUSB9261, TUSB8041-Q1

Long story short, I'm trying to read SATA drives with write blocking enabled. I'm using the TUSB9261 (USB 3.0 to SATA bridge) which does not seem to have native write blocking, so I was planning on using the write block function of the TUSB8041 (USB 3.0 4-Port Hub) since the IC is already in the design.

Would write blocking the USB line write block the SATA line? Does the TUSB9261 do a literal translation of commands (write, read, etc.) or does it process commands from the USB host and create its own commands to send on the SATA lines?

Thanks in advance,

Chris

  • 0
    TI__Guru* 76130 points
    Hello,
    I'm not familiar with the "write block" function on the TUSB8041, can you elaborate more about that?
    I will forward your question to the SATA experts.
    Regards
  • 0 in reply to Elias Villegas M.
    Prodigy 140 points

    On page 15 of the TUSB8041 datasheet, under the section SMBus Slave Operation, it mentions "When the SMBus interface mode is enabled, the TUSB8041-Q1 supports read block and write block protocols as a slave-only SMBus device."

    If this write blocking function is similar to the write blocking function of other similar devices, it means that the TUSB8041 will not issue any WRITE commands. This prevents the host device from changing anythings on the connected drives including user-driven commands and automated commands.

    I'm trying to block user-driven commands like creating or copying files into devices and automated commands like changing the "Date modified" and "Date accessed" properties of a file when they're opened.

    My ultimate goal would be to use the write block function of the TUSB8041 to block all write commands when reading a SATA with a TUSB9261, but I was wondering if the TUSB9261 issued write commands even if wasn't given any explicit write commands (i.e. read command from USB gets translated to a write command plus a read command). I'm not trying to block all outgoing signals, just the signals that result in a change to the drive being read.

    Thanks,

    Chris

  • 0 in reply to Christopher Williams79
    TI__Guru* 76130 points

    Hello,

    I'm a bit confused, per your description it looks like you are trying to "block" the data to pass through, however, the "write-block" that the TUSB8041 supports means you can send a chunk of bytes, a block of up to 32 bytes on the same write operation.

    Can you clarify?

    Regards

  • 0 in reply to Elias Villegas M.
    Prodigy 140 points

    Ah, I see. Thank you for the clarification. It wasn't the "write blocking" I was looking for. I was looking for write blocking in the sense that any write commands would be blocked, as in stopped, by the TUSB8041. There wasn't much detailing the write blocking so I took it in my own way. Since that's the case, I guess I don't have any other questions. I appreciate the help. You saved me quite a bit of time and money chasing shadows.


    Thanks,

    Chris