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TUSB4041I: TUSB4041I - OTP Programming necessary?

Zocker
Prodigy 40 points
Part Number: TUSB4041I


Hi,

ive made a custom design with the TUSB4041I.

Ive no eeprom or flash connected to the chip ... guessed the TUSB4041 has set std. values for vendor and product id.

But after i connect the device to my pc the device manager says: "Device stopped - Error getting usb-device descriptor"

So iam wondering if i have to set the vendor and device id trough OTP programming.

Please could someone give me a hint?

Thanks.

Regards

  • 0
    Prodigy 40 points
    OK. After little more investigation it looks like the device is in SMBus programming mode.
    The device draw a current around 230mA.
    Both pins, SCL/SMBCLK and SDA/SMBDAT, are floating in my design, so normally no SMBus programming mode should be entered, right?
    Iam not sure what happens at all.
    Someone a clue?
    Thanks and regards.
  • 0 in reply to Zocker
    TI__Guru 64326 points

    Hi,

    SMBus mode is entered when the SMBUSz pin is pulled low. Please ensure that this pin is pulled high at power on reset such that TUSB4041I does not enter SMBus mode. 

  • 0 in reply to Malik Barton57
    Prodigy 40 points

    Thx for your reply.

    Ive tested your suggestion, pulling SMBUSz high during power on. Unfortunately this didnt fix my problem.

    The datasheet says: 'The external interface is enabled when both the SCL/SMBCLK and SDA/SMBDAT pins are pulled up to 3.3 V at the deassertion of reset. The mode, I2C master or SMBus slave, is determined by the state of SMBUSz pin at reset.'

    SCL/SMBCLK and SDA/SMBDAT are booth floating in my design. So this should be ok, right?

    Testing a little bit more shows that SMBUSz is high after reset or power up. Datasheet says this pin is driven low after reset. So iam thinking about a damage of my device. Possible?

    How can i test if the device is working and only entered the SMBus programming mode?

    Thx a lot.

    Regards.

  • 0 in reply to Zocker
    Prodigy 40 points
    I solved my issue.
    I have a 1M resistor between USB Gnd and my board. This seems to be to heavy. With a lesser value the uplink is working.