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Getting Started With Linux on the LPC3250 OEM Board Page 32

4.4 Use DHCP

If you don’t want to or are able to assign a static IP address to the target board you can instead use

dynamically assigned IP addresses by using the DHCP protocol. Please note that a DHCP server must

be available on your network.

In the u-boot you need to exchange the

tftpboot

command for the

dhcp

command to load the

images using DHCP. For the Linux kernel you need to set the

argument to

dhcp

instead of using a

static IP address.

1. Boot into the u-boot console and change the ipaddr variable to dhcp.

uboot> setenv ipaddr dhcp

2. Change the

loadkernel_tftp

and

loadrootfs_tftp

variables.

uboot> setenv loadkernel_tftp dhcp $(loadaddr) uImage

uboot> setenv loadrootfs_tftp dhcp $(loadaddr) rootfs.jffs2

3. Update the

loadkernel

and

loadrootfs

variables.

uboot> setenv loadkernel $(loadkernel_tftp)

uboot> setenv loadrootfs $(loadrootfs_tftp)

uboot> saveenv

4. Boot Linux.

uboot> run bootcmd

4.5 Known Problems

4.5.1 Unable to Access USB Memory Stick

For some USB memory sticks you might need to specify which partition to use, not only which device

to use when invoking the

fatload

command. If this is the case for your memory stick and you are

using the default variables in the u-boot environment you need to update two variables;

loadkernel_usb

and

loadrootfs_usb

In the example below the

loadkernel_usb

and the

loadrootfs_usb

variables are updated to

specify partition 0 on device 0. Please note how the backslash character needs to be used before the

semicolon when updating a variable.

uboot> setenv loadkernel_usb usb start\;fatload usb 0:0 $(loadaddr)

uImage\; usb stop

uboot> setenv loadrootfs_usb usb start\;fatload usb 0:0 $(loadaddr)

rootfs.jffs2\; usb stop

uboot> saveenv

You also need to make sure to update the

loadkernel

and

loadrootfs

variables.

uboot> setenv loadkernel $(loadkernel_usb)

uboot> setenv loadrootfs $(loadrootfs_usb)

uboot> saveenv