Environment Variables - WAGO 750 Series Manual

9.5 Environment Variables

A list of all environment variables set can be viewed using
> printenv
An environment variable can contain values, further environment variables or
U-Boot commands. In the latter case, the environment variable works similar
to a macro which processes the commands one after the other.
The relevant environment variables for the Linux fieldbus coupler boot
process are:
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WAGO-I/O-SYSTEM 750
Linux Fieldbus Coupler
.
ipmode
Defines the type of IP configuration. Possible values are
static IP in the format xxx.xxx.xxx.xxx or a completely static
configuration in the format
<FBK-IP>:<ServerIP>:<GW-IP>:<Netmask>:<Hostname>:<Device>
10.1.1.8:10.1.2:1:10.1.1.254:255.255.255.0:lfbk:eth0
bootargs
Contains further parameters for the kernel, for example the root file system
(root=/dev/mtdblock3)
bootcmd
Contains a macro that creates a kernel command line from ipmode and
bootargs and starts the kernel. This macro is called automatically 3
seconds after starting the Linux fieldbus coupler (stored in the bootdelay
variable).
bootA/bootB
Macros that, depending on the selector switch position of the Linux
fieldbus coupler, are copied to bootcmd when U-Boot is started.
bootdelay
The time the system waits for the abort password to arrrive
ethaddr
MAC address of the Linux fieldbus coupler
Bootloader (U-Boot) • 189
Environment Variables
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bootp dhcp
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