[Milkymist-devel] MilkyMist for Altera, development environment

[Sébastien Bourdeauducq]

Hello,

On Thursday 18 February 2010 21:46:29 Gerard Braad wrote:
> Great to see 0.3 being released! As the
> demonstration shows at the end, developers are needed. I will provide
> help where possible to great an open source SoC

Thanks :)

I will post a list of things to be done in the next days.

> I would also like to start an effort to make MilkyMist work on Altera.

The difficult part with making ports that go beyond the "microcontroller with 
on-chip RAM" point is the off-chip SDRAM - not the FPGA manufacturer. Someone 
has already been successful running a basic SDRAM-less system based on 
Milkymist on the Altera DE2, without much effort.

Milkymist *requires* 32-bit DDR SDRAM to work, which most boards don't 
provide. Adapting it to other memories requires many modifications to the 
source code (and it would be a mess and a waste of time for me to maintain 
them all in the same code base).

> Has someone also undertaken any effort to use the Spartan-3E starter kit?

It has 16-bit DDR SDRAM, making a real port quite difficult.

> I have seen the Avnet Spartan3A port, but it is not officially
> maintained anymore (as fork)... motivation for this drop?

Lack of time to maintain several ports, especially ones that are not in the 
main scope of the project. The Spartan 3A board is way too resource-limited to 
render nice visuals. The port I did was merely an education and demonstration 
tool. It's best to keep this port as a fork, as it is more targeted as a 
general-purpose microprocessor system rather than a performance-driven design 
for fast graphics processing.

Sébastien