[En-Nut-Discussion] network throughput gain (nicrtl output)

[Harald Kipp]

At 13:32 01.12.2003 +1100, you wrote:
>Quoting Damian Slee <damian at commtech.com.au>:
>
> > Hi all,
> > our engineer here has found this Atmel ARM91
> > AT91FR40162-CI
> > >From memory;
> > 1MB flash
> > 16bit thumb instructions I think.
> > 256K RAM
> > 75MIPS
> > 32 IO
> > 8 chipselects for memory mapped stuff.
> > BGA package though.
> >
> > www.digikey.com has it listed for ~US$15.  Our local supplier in Western
> > Australia ~US$17.50 for MOQ 83 or whatever minimum pack size is.
> >
> > If we could find a stable GCC binary tool chain, certainly would be 
> having a
> > play some time in the new year.

I have some positive experience with the EB40A Kit
from Atmel. It comes with several commercial demos
and some freeware too. I liked WinIDEA.


>arm-elf tool chains are easy to build, but I wouldn't' discount the 
>mega128 just
>yet:
>-Dont' forget to debug any arm core you need some sort of jtag interface, 
>that
>alone will set you back $2200 USD.
>-Connecting any kind of peripherial will require some sort of level 
>transaltion
>if it's 5V (on 32 + 24 lines)
>-Anything you do connect will need to be fast enough, other wise you put 
>so many
>waitstates on the bus the ARM is waiting half the time
>-I think the 75 Mips quoted are with ARM instructions, with thumb, you will
>loose about 50%
>
>I'm saying all this from experience we have both ARM and MEGA128 based 
>designs,
>and there are heaps of cases where MEGA128 is a lot better suited.

As long as you don't need realtime boundary scan,
a simple JTAG interface (about 100 US$ or less) will
do.

The AT91R40008 seems to be a good choice. It got 256k internal
RAM (full speed 32 byte access), which should be sufficient
for Nut/OS. The external flash will only be used for
booting and perhaps some kind of file system.

The bad thing about this chip is: No DMA and almost no
integrated peripherals...not even SPI!

Harald