|Subject:||Re: [lwip-users] Delelop TCP/IP Stack for Microcontroller|
|Date:||Fri, 23 Nov 2012 12:52:53 +0530|
I've got lwIP working on another microcontroller of that family. I am not at liberty to publish any of the low-level code for the driver, but I can give you some hints. (One day it would be nice to re-write the code so that it could be published, but it is not easy to find the time for such work.)On 14/11/2012 11:22, Thirumalesha N wrote:
I'm new to lwip TCP/IP stack, I'm trying to implement udp
protocol for MPC5566 Microcontroller based controller card, I want
exhibit communication between controller card and PC(Running GUI based
application (UDP protocol implemented)).
I'm trying to develop TCP(UDP)/IP protocol for controller..how
do I proceed...?
The driver itself was heavily inspired by the Coldfire FEC example for lwIP. The MPC's FEC has a lot of functionality - it can do things like scatter-gather DMA so that you can have the IP header and the packet contents in different buffers in memory, or send out the different parts of a lwIP pbuf chain without doing any copying and concatenation in the program. However, it is also possible to ignore this - my driver code does the concatenation and copying so that the FEC code is as simple as possible. It is less efficient, but a lot easier to get working.
One thing to watch out for is that the FEC has it's own DMA engine that does not snoop the processor's cache (unlike the normal eDMA engine on the chip). That means you have to make sure caches are flushed around accesses to ram that the FEC accesses, or make sure that those memory areas are non-cached.
Hope that helps!
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