Monday, October 4, 2010

Lattice FPGA -- They are beginning to get OSS

After a quite a bit of comparative evaluation I chose the Lattice XP2 FPGA and the Brevia demo board for a bit of hardware hacking. (In short, I wanted a non-volatile FPGA or large CPLD, and found that the XP2 and MachXO seemed better than the Altera and Xilinx offerings).

And I'm happy to say that unlike my prior complaints about Cypress, I do think that Lattice "gets it" around open source hardware.

Al is not perfect, but they seem to be moving rapidly in the right direction.

First off, they recently obsoleted their old GUI and released their "Diamond" GUI for both Windows and Linux. Its a little crunchy still on Linux. However, this is a major, probably very expensive, initiative and Lattice should be commended for letting Linux be part of it! While they officially only support Red Hat, check out this output coming from the "compiler":

Warning: You are running on an unsupported platform
'synplify_pro' only supports Red Hat Enterprise Linux 4.0 and above
current platform: Ubuntu 10.04.1 LTS

That's right! I managed to get it up on Ubuntu 64 bit (I'll provide a little HOW TO in my next post).

Secondly, they priced the board extremely well at $29.

Third, they provide a lot of free libraries (called "designs" or "IP" in the hardware world) so long as you only use them on Lattice parts. Personally, I can live with that. After all Lattice is in the business of selling chips. And you know if I decide to switch chips, I can implement the underlying library myself and still have benefited from using Lattice's library to get me prototyping my application code faster...

Fourth, the GUI/compiler is free (well, its a 1 year free license so I guess someday they could take that away) and command line accessible.

Fifth, the USB programmer uses libusb, so you don't even need to install a special driver. This makes it a lot easier to run on different linux distros.

This is a great first step!!! Its perfect for OSS hackers and students.

... but there is stuff Lattice needs to work on.

First, my biggest gripe is that the Brevia board ships with a parallel port programmer. But who has parallel ports anymore? And by the way, purchasing a USB->parallel converter WILL NOT work. Those converters do not translate all parallel signals. Lattice FAEs claim some converters work, but will not endorse a particular one so we are left guessing.

In fact I was unable to get the parallel port programmer to work.

Second, the USB programmer purchased separately costs $150!!! This is an evil bait-and-switch. Honestly I haven't priced components out, but in this market I'd bet that USB components are cheaper than parallel because its all about volume. So what is going on here!!?

However its standard JTAG so other programmers should also work...

Third, the ispVM device programming tool was poorly ported to Linux. In particular, you actually specify the old 8088 parallel port number 0x378 (or whatever) to identify the parallel port, not the device name (and again I never got it to work with the parallel programmer).

Fourth, they only offer RPMs. Lattice, even if you don't want to support every distro, its traditional to just jam your program in a big gzipped tarball archive so we can pull it down and install it by hand by coping it to /usr/local or something along those lines.

And finally, Diamond is still a little rough around the edges. For example, sometimes the editor stops working and I have to close and reopen my project. Even worse, I managed to get my project into an inconsistent state where some generated files thought that certain clock resources existed but I had removed them. The easiest way out of that was to create a new project :-(, and copy my source code over.

However Diamond is very new. I expect very good things.

All in all its a great start! Thanks Lattice!

Disclosure: I am in no way affiliated with Lattice, other than having bought their $29 Brevia board...

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