S&T 44011-0208-13-2, Руководство пользователя

Страница: 57 / 65

pITX-iMX8M – User Guide Rev. 1.4
www.kontron.com // 57
7/ Bootloader Operation
7.1. Copyrights and Licensing of U-Boot
U-Boot is free Software. It is copyrighted by Wolfgang Denk and many others who contributed code. U-Boot can be
redistributed and modified under the terms of version 2 of the GNU General Public (GPL V2) License as published by
the Free Software Foundation.
Actual source code of pITX-iMX8M u-boot can be obtained from the git repository at
 https://gitlab.kontron.com/imx/u-boot-imx
PITX-iMX8M bootloader sources are derived work from a dedicated version of NXP development branch which is
hosted at source.codeaurora.org
 https://source.codeaurora.org/external/imx/uboot-imx.git
NXP work itself is based on mainline u-boot versions as hosted at denx:
 git://git.denx.de/u-boot.git
As a result, any bootloader for the pITX-iMX8M is based on a mainline u-boot version (e.g. v2020.04) and a branch in
NXP’s uboot-imx.git repository (e.g. imx_v2020.04_5.4.24_2.1.0) hosted at codeaurora.org.
7.2. Bootloader Quickstart
The PITX-iMX8M board comes with U-Boot preinstalled on the eMMC device. Follow the steps below to gain access
to the bootloader command line (CLI) on your host PC.
 Connect your host machine to the modules serial connector J19 using a flat ribbon DB9 adapter cable.
 Set the i.MX8M boot mode using the Boot Select DIP Switch SW1[1:2] to [Off:On] to select internal boot mode.
 Start a suitable terminal program on your host and attach it to the port connected with the board’s serial
interface. Configure the serial line using 115200 baud, 8 data bits, 1 stop bit, no parity.
 Connect power supply to the pITX-iMX8M and power up.
 When boot messages appear, press any key to stop automatic boot sequence.
After power on, bootloader boot messages will appear as shown below. There is a 3 second boot delay counter that
will try to boot linux OS automatically after expiration. Pressing any key will stop the boot delay counter and enter
the bootloader CLI.