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TUSB8043: TUSB8043 I2C timing diagrams

John DeCesare
Intellectual 390 points

Part Number: TUSB8043
Other Parts Discussed in Thread: PCA9536

Hi,

I cannot find any typical I2C timing for the TUSB8043. I'm look to see how to read the Vendor ID and if I need to initially write to the device to set the address and then read? Typically, I2C devices have the single byte read and write diagrams. Are these available for the TUSB8043?

Thanks!!

John

  • 0
    TI__Guru**** 159725 points

    Hi John:

        You can only read vendor ID in SMBUS mode ( SMBUSZ is low), CLK frequency is 100kHz . 

        Make sure to clear activecfg bit in register F8 to exit SMBUS programming mode after read or write any register.

    Best

    Brian

  • 0 in reply to Brian Zhou
    Intellectual 390 points

    Hi Brian,

    Thanks for the fast response. Most appreciated!!  What I was actually looking for are pictures of the read and write transactions on the I2C bus. For example, if you look at section 8.6.4 in the PCA9536 datasheet, it shows pictures of the transactions on how to read and write.  I just don't know if I need to write to the TUSB8043 to set the register that I want to read if that makes sense.

    Thanks!!

    John

  • 0 in reply to John DeCesare
    TI__Guru**** 159725 points

    Hi John:

      Are you talking about I2C for EEPROM  or I2C over HID?

       For I2C for EEPROM, hub is master, I2C is follow  normal I2C spec and waveform

    Best

    Brian

  • 0 in reply to Brian Zhou
    Intellectual 390 points

    Hey Bria,

    I have a processor connected to the TUSB8043 (SCL/SDA) and I want to read the Vendor ID so I know that the I2C bus is good.  I don't have an EEPROM on the board.  I have the processor attempting to read the ID (address 0x01) and I can see the transaction go out at address 0x88 and the TUSB8043 is ACKING but I just want to know how to read the ID. I'e attempted to write a 1 to the device thinking that sets the register for the next read but that isn't working. I'm reading back all 0's.  

    Thanks!

    John

  • 0 in reply to John DeCesare
    TI__Guru**** 159725 points

    Hi John:

      Pulldown SMBUSz pin , you can read  any register  by I2C master. I2C address is based on  1000 1xy.

      x is the state of GANGED

       y is the state of FULLPWRMGMT

      if x, y is 0, address# is 44.

    Best

    Brian