How to configure JetsonTX1 UARTB at UBOOT?

hi,all,
we need TX1 can receive/send CMD via UARTB at UBOOT, so I try to configure UARTB at board_f.c of UBOOT but not success, it follow the below process,

  1. assert UARTB reset
  2. enable UARTB clock
  3. delay 2us
  4. de-assert UARTB reset
  5. configure UARTB reg DLL/DLH for Baudrate, source clock is 408MHZ, baudrate is 115200。
  6. configure FCR[0] with 1.
  7. write UARTB THR reg to output data via UARTB
    UARTB hasn’t output, and TX signal always is 3.3V.

i have compare register of UARTB and UARTA, all are same,but UARTA can work with the same process.
Is the previous configuration process wrong?

thanks!

hello am.xiao,

seems there’s issue with UART console,
could you please refer to this tutorial page, https://www.jetsonhacks.com/2015/12/01/serial-console-nvidia-jetson-tx1/
thanks