Usage: linux-serial-test [OPTION]

  -h, --help
  -b, --baud        Baud rate, 115200, etc (115200 is default)
  -p, --port        Port (/dev/ttyS0, etc) (must be specified)
  -d, --divisor     UART Baud rate divisor (can be used to set custom baud rates)
  -R, --rx_dump     Dump Rx data (ascii, raw)
  -T, --detailed_tx Detailed Tx data
  -s, --stats       Dump serial port stats every 5s
  -S, --stop-on-err Stop program if we encounter an error
  -y, --single-byte Send specified byte to the serial port
  -z, --second-byte Send another specified byte to the serial port
  -c, --rts-cts     Enable RTS/CTS flow control
  -e, --dump-err    Display errors
  -r, --no-rx       Don't receive data (can be used to test flow control)
                    when serial driver buffer is full
  -t, --no-tx       Don't transmit data
  -q, --rs485       Enable RS485 direction control on port, and set delay
                    from when TX is finished and RS485 driver enable is
                    de-asserted. Delay is specified in bit times.

linux-serial-test -s -e -p /dev/ttyO0 -b 3000000

linux-serial-test -y 0x55 -z 0x0 -p /dev/ttyO0 -b 3000000