A new LinuxDevices.com
article summarizes Andrey Filippov's latest paper on FPGA use
entitled, How to use
Free Software in FPGA Embedded Designs (PDF format). Filippov
recently designed a high-res
network camera utilizing an FPGA and, when Xilinx asked him to write
an article about it, he realized the need to educate others on the Open
Source and Free
Software that's available for use with FPGAs. The
article covers everything from development tools to selection of the
right FPGA for the job. If you're thinking about using an FPGA or CPLD
in your next robot, this article makes a good introduction to the topic.
The "free software" that he used for the FPGA design itself is actually
proprietary Xilinx software that they offer a free version with limited
capailities, or in other words it's "free as in beer", meaning it
doesn't cost anything as opposed to being open source software.
Are there "free as in speech" tools for FPGA development?
We did an article a
while back on Icarus, a
Free (as in speech) Verilog simulation and synthesis tool. You can do
the design in Icarus and there are also GPL'd tools for downloading your
code to chips like the Xilinx via JTAG. But, if memory serves, their is
still one step along the way where you have to use a proprietary Xilinx
tool to place-and-route and generate the configuration bit stream for
the chip (it is, however, a free [as in beer] tool and can run on Linux
under Wine). Hopefully, Xilinx will free the source to this tool or it
will likely be reverse-engineered and freed anyway.
There is a Xilinx
on Linux How-To that might have more details.
And you can probably find other Free (as in speech) CPLD and FPGA
software at the OpenCollector.org site.