[Milkymist-devel] segfault simulating milkymist with icarus

[Sébastien Bourdeauducq]

Hi,

On Saturday 28 November 2009 16:33:26 you wrote:
> I've started the implementation of milkymist for the Digilent Spartan3E
> Starter Kit and Digilent Spartan3E Development Kit boards. I've had to
> change some parts of the design and I'm planning to integrate yadmc and
> wb_ddr from das labor to be able to make use of the integrated ddr module
> and the sdram daughter board.

Why don't you use Milkymist's integrated HPDMC controller?
It already supports DDR and can be modified for SDR by simply replacing the DDR 
I/O registers with normal flip-flops and adapting the init sequence in the BIOS.
It should be faster than the other controllers you mention (lower latency and 
higher bandwidth) and directly compatible with the Milkymist peripherals which 
use FML (video out and TMU).

> I've been trying to simulate the system using
> icarus verilog using the milkymist testbenchs but it throws a segfault on
>  my ubuntu 9.10 box. I've tryed with icarus from ubuntu repos (9.1-1
>  karmic) and from icarus website (0.9.1 also). Both of them give the same
>  results. At first I thought it was a problem with my port to xilinx-s3sk,
>  but tried wit ml401 and it was the same... Do you know if it is the same
>  for other people simulating milkymist?

That's a known issue - some wicked constructs in LatticeMico32 crash Icarus 
Verilog and GPL Cver.
The current workaround is either to use an older version of LatticeMico32 (you 
can find them from Lattice Semiconductor's FTP site) or to use a non-free 
simulator, such as Modelsim (there is a free of charge version available from 
Xilinx, though I do not know what it is worth).
The perfect solution would be to fix the bugs/implement the missing features in 
the free simulators.

Sébastien