Terminal Connection


  1. Connect the Debug UART (D-Sub 9, TTL pin header).
  2. Start Terminal program (Terminal Settings).
  3. Connecting the 5V DC power your board will boot.
  4. To prevent the OS from being started, but rather enter the U-Boot command loop, press any key as soon as or before the message:
Hit any key to stop autoboot:

is displayed.


Pressing CTRL + C at this point will not only abort the autoboot but also skip U-Boot hardware initilization, incl. skipping reading some variables and settings from the environment, thus leaving the COM in a recovery state. This can be useful to recover from a situation where some environment setting causes U-Boot to crash or hang.
This state is acknowledged with the message:

<CTRL-C> detected; safeboot enabled

Terminal Program

For terminal program following are recommended:


Under Linux all above are usually available via the distribution’s package manger.

Terminal Settings

The communication parameters required for the serial port are:

Setting Value
Baud rate 115200
Data bits 8
Parity None
Flow control None or Xon/Xoff [1]
[1]Disable hardware handshake (RTS/CTS)

Power-On and Reset Output

After power up or reset, output of U‑Boot will appear on the console similar to this:

U-Boot 2015.10-rc2-04843-ge1be59f (Oct 23 2015 - 12:57:17 +0200)
CPU: Freescale i.MX6SOLO rev1.2 at 792 MHz
Temperature: Industrial grade (-40C to 105C) at 54C - calibration data 0x59a50669
Reset cause: POR
I2C: ready
DRAM: 256 MiB
Board: Ka-Ro TX6S-8034
VDDCORE set to 1350mV
VDDSOC set to 1350mV
NAND: 128 MiB
IPU HW Rev: 4
Baseboard: stk5-v3
MAC addr from fuse: 00:0c:c6:7c:6a:6d
Net: FEC
Hit any key to stop autoboot:  0
TX6S U-Boot >