RTM-ATCA-SXXX Overview

3.6.1U-boot console tool

The ATCA-S201 employs a staged boot process that begins with U-boot. U-boot is an open source boot loader program that is the first code executed at system reset. As the boot execution commences, its progress may be monitored via the RS232 console port of the Advanced RTM. U-boot supplies several initialization parameters to the Linux kernel that administrators may elect to modify. U-boot employs a countdown timer with a default setting of bootdelay seconds, see table below. If a key is pressed before this time, the auto boot procedure halts and the administrator will see a U-Boot command prompt:

...

Hit any key to stop autoboot: 5 uboot=>

3.6.1.1When is U-boot needed?

Users may never need the U-boot environment. U-boot is included to accommodate atypical system maintenance situations such as:

On site field servicing (must be connected via serial console)

Network boot (rather than flash boot)

Environments without a DHCP server

Flash recovery

3.6.2Essential U-boot user commands

The U-boot console environment includes a rich set of commands that can be listed on the screen using the following command:

uboot=> help

Typically, only a handful of commands are needed to configure a new ATCA-S201. The essential commands are covered in the table below.

Table 8 Essential U-boot configuration commands

U-boot command syntax

description

 

 

printenv

Displays a list of all U-boot environment variables and

 

their current values. See section 3.6.3 for details.

setenv <variable_name>

Used to create or modify a U-boot environment variable.

<new_value>

New variables will be automatically created, existing ones

 

overwritten. When called without a <new value>, it will

 

delete the matching <variable_name> from the U-boot

 

environment if it exists.

saveenv

Used to saves environment variables to flash device,

 

which is loaded upon subsequent system power cycle or

 

reboot.

 

Variable changes that are not saved exist in RAM only,

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Emerson ATCA-S201 manual Boot console tool, Essential U-boot user commands, Boot command syntax Description