[ell-i-developers] Re: IP/UDP/CoAP status

  • From: Pekka Nikander <pekka.nikander@xxxxxx>
  • To: ell-i-developers@xxxxxxxxxxxxx
  • Date: Sun, 2 Mar 2014 22:58:24 +0200

I implemented pcap support to a mockup test platform, so that when running 
under the emulator the stack is now able to receive real packets from a file 
and send packets to standard output, in pcap format.  I also implemented a very 
simple ICMP echo support.

With this test platform, I have now been able to debug and fix the quite a few 
bugs in the Ethernet, IP and ICMP layers.  The code now replies to ping.  UDP 
and CoAP are still to be tested.  ARP and DHCP remain to be written.  Hence, I 
believe we are in good shape for having working CoAP on Tuesday or Wednesday 
latest.  DHCP most probably quite much later, as it requires timers and other 
state requiring functionality.

While I'm not able to produce real binaries yet (due to some missing stuff 
between ENC28J60 and Ethernet layer), the approximate binary size at the moment 
is 3.5kB.  Hence, I have all the reason believe that the final working version 
with a working ARP/IP/ICMP/UDP/CoAP will take less than 4k.  DHCP most probably 
fits into less than 1k, and therefore the final CoAP-capable runtime is likely 
to fit into 5k.  Hence, in theory at least we should be able to support the 
lowest end Cortex-M0 chips with just 2-4k of RAM and 8k of FLASH, e.g. NXP 
LCP1100XL.  Of course, at the moment we don't have drivers for any NXP 
peripherals, but if we want to go there that is not such a big deal.  At the 
STM side we should be able to use STM32F030, which should cost around 30 cents 
in mass quantities.


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