Re: [Contiki-developers] about interrupt driven reception

[Spiro T. <tri...@gm...>]

Hello Johnny,

* On Tue, Mar 15, 2005 at 05:23:27PM +0100 Johnny Karlsson wrote:

> Has anyone a good idea on how to implement a interrupt driven
> function? My first attempt looks like this:

[snipp]

If I understand your approach correctly, your writing the packet from
the NIC directly in the UIP buffer. This will not work, because you
could overwrite some contents (in the UIP buffer) which are currently
scanned by other functions!

Personally, I'd use a buffering approach: Whenever an interrupt occurs,
get the data from the controller and put it into a buffer. Now, whenever
uIP wants to poll for another buffer, check if there is something in
that receive buffer.

If memory is a problem, you might want to restrict yourself to two
buffers only: The UIP buffer, and a "shadow" buffer which is written by
the interrupt routine. Anyway, make sure you do not write into the wrong
buffer while it is read/written by "the other side", thus, you need
correct synchronization mechanism.

Regards,
   Spiro.

-- 
Spiro R. Trikaliotis
http://www.trikaliotis.net/
http://cbm4win.sf.net/