[En-Nut-Discussion] Nut/Net ARM port

[Henrik Maier]

Hello folks,

There seems to be a considerable interest in Nut/OS for the ARM 
architecture.

And it is readily available for Ethernut 3, based on the AT91R40008 
ARM7TDMI CPU. Ethernut 3 is well speced with lot's of RAM and Flash and 
certainly a good successor of Ethernut 1 and Ethernut 2.

A few people including myself are interested in a small scale ARM7 
Nut/OS incarnation, featuring the Philips LPC or Atmel AT91SAM CPUs with 
memory footprints similar to Ethernut 1/2 designs (32 to 64 KByte RAM, 
128 KByte to 1 MByte of FlashROM).

Q1: The question to me is, how much RAM and Flash would be needed for an 
ARM7 based Nut/OS, featuring similar capabilities/power like Ethernut 1/ 
Ethernut 2 designs.

Q2: And then, what would be a good choice for a NIC? Using the RTL8019AS 
known from Ethernut 1, the LAN91C111 from Ethernut 2, the DM9000E 
introduced by Ethernut3, the Microchip ENC28J60 or the integrated MAC 
from AT91SAMX series.

RTL8019AS pros: Nut/OS driver already available, only needs to be ported 
from AVR to ARM, reasonably cheap NIC
RTL8019AS cons: Access timing can be tricky due to missing IOCHRDY 
signal, 10 MBit only.

LAN91C111 pros: Nut/OS driver available
LAN91C111 cons: ?

ENC28J60 pros: Reasonably cheap NIC
ENC28J60 cons: power consumption, no Nut/OS driver yet available, 10 
MBit only

DM9000E pros: Nut/OS driver available
DM9000E cons: ?

AT91SAMX pros: Integrated NIC, DMA access promises high speed transfers 
according to Atmel's documentation.
AT91SAMX cons: No Nut/OS driver yet available

Q3: As there are more people out there, what would be the best approach 
to share information and collaborate on this topic?


Henrik Maier
www.proconx.com