[En-Nut-Discussion] Generals Questions About Ethernut

[Harald Kipp]

Hello Andreas,

At 10:13 09.08.2005 +0200, you wrote:
>My first thought was about security. I mentioned SSL-Encryption but with 
>no clue about the perfomance question. So
>does anyone know anything about a Atmega128 performing SSL communication 
>while simultaneously performing other actions (especially doing network 
>related "things" or reading writing ports n stuff) and if not will the 
>AT91R40008 (EN3) be sufficient ????

Good question, as far as the ATmega is involved. In fact Rabbit
Semiconductors is the only implementation of SSL on an 8 bit
machine I've heard of. Rabbit considers AVR being 16 bit machines
and I consider the Rabbit CPUs not being one of the fastest 8 bitters.
Thus, it might be possible.

Any kind of encoding and decoding of data streams is the major driving
force behind porting Nut/OS to the ARM CPU. The 256 kByte RAM on
Ethernut 3 will not add much, but > 10 times the performance of
Ethernut 1/2 will open up new applications, including SSL.

>My second question is about evaluating the Ethernut-solution as a future 
>plattform.
>Are there any infos about the power comsumption of the EN3-Board ?? I'm 
>especially thinking about Power over Ethernet - wich was one of the (many 
>:o) ) main reasons to choose Ethernut in the first way.

Another good question. The estimated power consumption varies
between 57.5 mA and 542.5 mA at 3.3V. Most of it is consumed
by the CPLD and the 100 MBit transmitter. However, for most
applications the CPLD will contain a static design (not clocked).
And using 10 MBit Ethernet will reduce consumption by 60 mA.
Thus, typical applications may require 180 mA peak at 3.3V.
Luckily Ethernut 3 is equipped with a switching power supply,
providing 70% worst case efficiency. Generally speaking,
compared to Ethernut 1 and 2, Ethernut 3 can be a real power
saver.

Harald