So what is the verdict now? I found this thread because I was researching the HK4K 144pin, probably for the same reasons as you guys, I want a small scale FPGA which can haz PLL and fast clock delay line taps.
Well, for this price level the clocking resources are pretty good. I mean, it's got a PLL. Nuf said.
Things like FF toggle rate are a bit low (256 MHz max), but VCO frequency is quite decent (533 MHz max). And quite interestingly they have local clock inversion, which I've not seen before on this type of el cheapo fpga. So on the models with 2 PLL's you could generate 4 staggered clocks (0,90,180,270 degrees) at say 500 MHz which is quite nifty. Then with some clock enables you'd clock the FFs at 250 Mhz.
Oh and they have 150 ps step size for the delay adjust. Not super, but again ... for this price level that's damn nice.
As for tools, I just spent some time playing around with it. After I told the licence dude/dudette my favorite color and underwear preferences they favored me with a license.
Short version:Tools are a bit of a mixed bag, but overall definitely positive.
Pending any suckage level updates where applicable.Long version:The icecube2 gui definitely feels a little klunky. Earlier on Mike described it as "
a bunch of random tools held together with sticky tape", but he was being generous. They probably started out with the intention of using sticky tape, only to find out they were all out of tape. So they used hot glue for some parts, but then the glue gun went *ffzzzt* and they had to tack the rest together with silly putty and hope for the best. The internal editor ... has no syntax highlighting. Seriously?
The workflow is not super, but not as bad as was mentioned earlier. For the icestick board I could just download the kit design files and use the project files. Press the magic BUILD EVERYTHING & STUFF button and off we go. Runs everything, including generating the .bin file. The floorplanner is rather limited. It's just about enough to inspect for correct placement but that's about it. No tcl scripting to quickly select your fav resources + do some highlighting. You can drag & drop to fuck up your placement constraints, but not sure yet if I like it.
The BIG WIN for me is that it
does support SystemVerilog for synthesis. Yay! Of course the silly putty gui doesn't support it. That would just be too easy. But they do use synplify pro as backend, and you can also run the gui. You can even run the gui at the same time and do a batch run, something that's not always possible with some of the free licenses. So basically the mission is to use icecube to cobble together a project and then get into synplify pro as quickly as possible. At least there you have a decent environment (oh look, syntax highlighting
). And as said, the free license comes with sysv support.
Integration between synplify & icecube is what you would expect for silly putty. Should you
reeeeaaaally like the icecube gui, you can also enable SystemVerilog for that flow. You'll have to manually edit the project file to change the verilog mode from v2001 to sysv. But basically you'll want to do everything in synplify except for floorplanning. Well, and the pll wizard generator thingy.
And of course simulation just
has to be total shit.
They use Aldec, which means windows only. No biggie, but it would have been nice if they used modelsim. But oh well, can't complain for a free license. Besides, it looks like modelsim is also possible, but I still have to do the simulation library dance...
Anyways, icestick (ICE40HX1K, aka TQFP144 package with 1 PLL) ... only $25 at digikey/mouser. You know you want to!