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Hobbyist-friendly FPGA?

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cyberfish:
Hello,

I have been using a Xilinx FPGA in my designs for a while (Spartan-3AN 50K). It works fine, but I'm running out of LUTs as my designs get more complex, and would like to switch to larger FPGAs. The problem is, large FPGAs from Xilinx and Altera are only available in BGA. I can solder TQFP's pretty easily. The biggest TQFP chip Xilinx has is the Spartan-3 200K. It's an older generation, and is really not that big. The Spartan-3A/AN only has 50K gates version in TQFP-144.

As a result, I have been looking at Lattice FPGAs. They have fairly high end chips in QFP. Does anyone have experience with them? How do they compare to Xilinx/Altera both in terms of silicon and tools? Cost is secondary as I'm not mass producing these projects.

Thanks!

mikeselectricstuff:
I've used the very low-end Lattice (EC)  parts - software is fine - much of it will look VERY familar to a Xilinx ISE user.
It's free but need to renew license every 6 months which is annoying (done instantly over web though so no big deal).

Looks like there aren't yet any Chinese knock-offs of the Lattice JTAG cable, but ISTR they were planning to use the  FTDT FT2232H as a JTAG interface - may be worth looking at what their ISPVM pogramming SW currently supports.

One nice thing which I'm not sure Xilinx supports, is that when using a SPI config prom, you can program it via the JTAG port so no need to swap programming cables around. Lattice also have parts with onboard config memory.   

allanw:
What about using FPGA module/breakout boards?

cyberfish:

--- Quote ---I've used the very low-end Lattice (EC)  parts - software is fine - much of it will look VERY familar to a Xilinx ISE user.
--- End quote ---
That is good news! The software is the part I worry the most (besides the fact that Digikey doesn't have Lattice chips...).

I'm not sure why there are no clones yet. They even publish the schematics! (http://www.latticesemi.com/documents/an8082.pdf?jsessionid=f03028227870e7cbf51418235d214c593d63). And unlike Xilinx/Altera, there's no CPLD on there with proprietary logic.

I really like how they open up a lot of things. The programming cable schematics and (more importantly) LatticeMico32 soft core (with GCC support!!).

Definitely giving them a try on my next project.


--- Quote ---One nice thing which I'm not sure Xilinx supports, is that when using a SPI config prom, you can program it via the JTAG port so no need to swap programming cables around. Lattice also have parts with onboard config memory.
--- End quote ---
Yeap Xilinx supports configuring SPI prom indirectly, too. There's only one series from Xilinx that has non-volatile memory - the Spartan-3AN, but it's basically just an SPI flash chip and the FPGA in the same package, with some software magic.


--- Quote ---What about using FPGA module/breakout boards?
--- End quote ---
I'm somewhat against breakout boards, because I like my designs to be smaller. Sometimes that's necessary, sometimes just nice. And also because I couldn't find any reasonable one. Sparkfun has Altera and Xilinx breakout boards for TQFP chips... but I can solder those myself, too.

mikeselectricstuff:

--- Quote from: cyberfish on April 06, 2011, 01:59:06 am ---
--- Quote ---I've used the very low-end Lattice (EC)  parts - software is fine - much of it will look VERY familar to a Xilinx ISE user.
--- End quote ---
That is good news! The software is the part I worry the most (besides the fact that Digikey doesn't have Lattice chips...).

--- End quote ---
Mouser and Farnell do, although they are expensive. If you're buying for production talk to a franchised distributor for the magic 'supported pricing' which can be half that of broadline distributors. Smaller FPGA companies like Lattice are desperate to get design wins from the big two, so if you tell them you're migrating from a Xilinx part they will be helpful.

--- Quote ---
I'm not sure why there are no clones yet. They even publish the schematics!

--- End quote ---
Lower demand I suspect

--- Quote ---And unlike Xilinx/Altera, there's no CPLD on there with proprietary logic.

--- End quote ---
Don't know  about Altera but the Xilinx software programs/updates the CPLD automatically.

--- Quote ---I really like how they open up a lot of things. The programming cable schematics and (more importantly) LatticeMico32 soft core (with GCC support!!).

--- End quote ---
Someone has even used this core on  a Xilinx project..!


--- Quote ---What about using FPGA module/breakout boards?
--- End quote ---
I'm somewhat against breakout boards, because I like my designs to be smaller. Sometimes that's necessary, sometimes just nice. And also because I couldn't find any reasonable one. Sparkfun has Altera and Xilinx breakout boards for TQFP chips... but I can solder those myself, too.
[/quote]
Enterpoint do some higher-end FPGA breakouts

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