[chbot] FPGAs again ... Info so far

[Charles Manning]

Hello All

Prompted by various bits of feedback, herewith a roll-up of all the 
information I have been able to glean so far.

#disclaimer. There might be some errors...

Board

The board of interest is the Terasic DE0-Nano which has an Altera Cyclone Iv 
with 22k "logic elements". 32Mbytes of SDRAM, easy to access 3V3 level IO 
pins etc etc.

http://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English&No=593

It is hard to compare effective gate size between architectures, but it is 
worth noting that a 32-bit Nios2 CPU uses approx 700 LEs. ie a small 32-bit 
CPU takes up approx 2.5% of the logic.

It costs USD79 + shipping (USD10-15) = total of around USD90. For genuine 
students there might be a $20 discount, but I'm not prepared to try cheat 
them.

Tools

Free Web Edition versions of tools are available for both Windows and Linux. 
Not 100% sure what level of support there is for Linux, but scratching around 
on the forums show people using Ubuntu, Suse and RedHat.

The tools include the ability to generate FPGA logic images as well as an IDE 
to develop/debug Nios software.

Soft CPUs

The free tools include unhindered use of the Nios2/e (limited stripped version 
of the Nios2 32-bit CPU. This version lacks caches and MMU so will not run 
Linux on the target. It will run ucLinux and various RTOSs though.

The free tools include restricted versions of the more capable Nios2 CPUs 
which do have MMUs anc caches and should be Linux capable. The CPU must 
however be run either tethered to the development host or otherwise only runs 
for a fixed period before halting.

The NIOS is interesting in that it is really easy to add up to 256 custom 
instructions. That means interesting manipulations which might take many 
instructions on a general purpose CPU can be potentially encoded as a single 
instruction.

Other soft CPUs are available from opencores.org and elsewhere and include 
OR1K, LEON (SPARC) and others.

Ordering

I intend to put in an order at the end of the week.

So far boards will be ordered for:

Myself
Timothy
Richard
Volker Kuhlmann
Paul Davey

Delivery should be less than 1 week.

If you want to be added/removed from this list, please contact me on or off 
the list.

Regards

Charles