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TUSB1210 in UART mode

Jamaal_Charles
Genius 3245 points
Other Parts Discussed in Thread: TUSB1210

Hello,

We are currently using the TUSB1210.  When we use it in UART mode, which pin is the TX (output) and RX (input) to the chip?  From figure 5.1 in the datasheet, our assumption is DP is the input and DM is the output.  However, we don't see that stated anywhere, and want to confirm.  DM is connected to pin 2 on the USB connector, which is an input (I believe), DP to pin 3 (output), so, we want to verify what to expect in UART mode.

Thank you

  • 0
    TI__Genius 11280 points

    Hello Jammal,

    Both RXD and TXD are multiplexed in ULPI interface. In UART mode, pin 3 and Pin 4 becomes TXD and RXD respectively.

    Regards,

    Gerardo

  • 0 in reply to Gerardo
    Genius 3245 points
    Thanks Gerardo,

    We are more concerned/interested in what pins 18 and 19 do in UART mode. Figure 5-1 seems to infer that TX and RX are passed through to the USB pins. Also, the wording in 5.3.1.3.6 says:
    "In this mode, the ULPI data bus is redefined as a 2-pin UART interface, which exchanges data through a direct access to the FS/LS analog transmitter and receiver"

    Do the UART signals get passed to the USB DP/DM pins? That is what we are hoping for, and why we need to verify which pin is the input and which is the output. If the UART signals are just being converted to USB, we will need to change our solution and come up with a different method.

    Thanks for looking into this for us.
  • 0 in reply to Jamaal_Charles
    TI__Genius 11280 points

    Hello Jamaal,

    Yes, the UART signals get passed to the USB DP/DM pins.

    Regards,

    Gerardo

  • 0 in reply to Gerardo
    Prodigy 185 points
    Gerardo,

    What would the electrical specifications be for the UART mode on the USB DP/DM pins? I am interested in this mode too and want to make sure I can connect directly to the USB DP/DM with 3.3V interface. Also, according to Figure 5-1 in the TUSB1210 specification, it looks like DP maps to the UART RX function and DM maps to the UART TX function (from the TUSB1210 perspective). Is this correct?
  • 0 in reply to Bill Whitehead
    TI__Genius 11280 points

    Hello Bill,

    You can see more detail about the UART mode in the references below:

    a) ULPI spec version 1.1

    b) USB analog carkit interface specification CEA-936a

    Regards,

    Gerardo