topic Re: How can i change the IP in run time in ColdFire/68K Microcontrollers and Processors

How can i change the IP in run time

faustino — Fri, 07 Aug 2009 07:48:05 GMT

Hi all

I am using M52233 demo board with Coldfire lite stack and the web server, but I want to know how can I change the ip adress in run time. For example, if I write into the LCD the IP adress and use that adress without have to restar the micro.

thanks and excusme for my bad english.

Re: How can i change the IP in run time

PaoloRenzo — Sat, 08 Aug 2009 01:56:30 GMT

Why resetting is not an option? Have you considered software reset? Using CF registers, a software reset is different from a hardware reset, you firmware can handle both events indepently at start-up

Re: How can i change the IP in run time

MCF52233 — Tue, 11 Aug 2009 11:41:51 GMT

Hi,

definately reset is good option becoz consider a scenario where communicarion is going on

with microcontroller n suddenly u change d IP but arp entries are associated with the previous

IP address. When u reset then there is communication drop n arp entries get changed.

Re: How can i change the IP in run time

mjbcswitzerland — Tue, 11 Aug 2009 18:50:56 GMT

On-the-fly IP changes are used quite often in the uTasker project so generally it should not be a real difficulty. When the new IP settings are committed, the ARP table is flushed and so there is an orderly change.

Regards

Mark

www.uTasker.com
- OS, TCP/IP stack, USB, device drivers and simulator for M521X, M521XX, M5221X, M5222X, M5223X, M5225X. One package does them all - "Embedding it better..."

Re: How can i change the IP in run time

bkatt — Wed, 12 Aug 2009 20:01:34 GMT

faustino wrote:

I am using M52233 demo board with Coldfire lite stack and the web server, but I want to know how can I change the ip adress in run time.

Just follow what the Niche code already does in set_ipaddr() (NRMENUS.C) or dhc_setip() (DHCPCLNT.C). The DHCPCLNT.C code is a little smarter about setting the mask, default gateway, and broadcast addresses.

There's a warning about "setip will kill all current net connections!" but it is overstated. Changing the IP will make any connected TCP sockets unreachable. You may want to take action to close them before the change.

The local ARP table is not affected by this change, as it tracks IP addresses of other hosts. Those other hosts may have copies of your previous IP address in their ARP tables, which will eventually expire.