Electronics > FPGA
Being Stuck with Efinix
gnuarm:
I'm redesigning a rather small board because the FPGA was EOL 8 years ago and I just can't build them anymore. I wanted to use a Gowin part, but the customer who does business with the US government said "no" to the Chinese company.
The Trion T13 should do the job, but it's a bit hard to tell because of the use of logic cells for routing. The T13 is way oversized from the 3 klut part the design was squeezed into, so it should work fine.
But... I don't like the packaging. The packaging choices are F256 on 0.8 mm centers and F169 on 0.65 mm centers. So bad and worse from my perspective. Both packages are upward compatible with the T20, and not downward compatible at all, so more reason to go with the T13 and not the T8.
Any advice on routing a 0.8 mm BGA? I seem to recall this being discussed and someone had laid out a board for JLCPCB and managed to make it work with their design rules, but I'm thinking they got it to work, but the via pads were shrunk or chopped or something. Anyone remember that thread?
I also really don't like the fact that they make you pay to try out the tools. I know, you aren't buying the software, you are buying some hardware, but what's the diff? It's goofy and that makes me wonder about them.
Anyone using their parts? Do they support VHDL well? Do they have their own tools or is it a mainline HDL supplier?
asmi:
--- Quote from: gnuarm on January 05, 2023, 04:07:51 am ---Any advice on routing a 0.8 mm BGA? I seem to recall this being discussed and someone had laid out a board for JLCPCB and managed to make it work with their design rules, but I'm thinking they got it to work, but the via pads were shrunk or chopped or something. Anyone remember that thread?
--- End quote ---
No need for any threads, one just need to look at their published capabilities. 0.8 mm pitch BGAs are absolutely not a problem, even with 0.1 mm trace/spacing (their limit is 0.09 mm) you can easily fit a trace between their standard 0.2/0.45 mm vias at 0.8 mm pitch (they have a premium option of 0.2/0.4 mm via if you absolutely require it), not to mention between pads.
If you want a specific example, look at the project in my signature - DDR2 memory module has a pitch of 0.8 mm, it was manufactured by JLCPCB 3 years ago and as you can see there are no manufacturing problems whatsoever.
woofy:
--- Quote from: gnuarm on January 05, 2023, 04:07:51 am ---The Trion T13 should do the job, but it's a bit hard to tell because of the use of logic cells for routing.
--- End quote ---
Some time ago I ran a custom cpu out on the Xyloni module (Digikey 2134-XYLONI-ND) with a small program to increment a counter, output to the leds, delay and repeat.
It uses 753 LE's and runs at 47MHz. For comparison, the ice40 HX8k using yosys/nextpnr uses 618 LC's and runs at 80MHz.
The C2 speed grade on the Xyloni board is the slowest one. The C3/C4 grades available on the 144 pin QFP may equal the HX, but I never tried them.
gnuarm:
--- Quote from: woofy on January 05, 2023, 10:39:59 am ---
--- Quote from: gnuarm on January 05, 2023, 04:07:51 am ---The Trion T13 should do the job, but it's a bit hard to tell because of the use of logic cells for routing.
--- End quote ---
Some time ago I ran a custom cpu out on the Xyloni module (Digikey 2134-XYLONI-ND) with a small program to increment a counter, output to the leds, delay and repeat.
It uses 753 LE's and runs at 47MHz. For comparison, the ice40 HX8k using yosys/nextpnr uses 618 LC's and runs at 80MHz.
The C2 speed grade on the Xyloni board is the slowest one. The C3/C4 grades available on the 144 pin QFP may equal the HX, but I never tried them.
--- End quote ---
When you say the Efinix used 753 LEs, does that include the ones used for routing? My understanding is they don't have dedicated routing, right? Or am I mixing this up with another brand?
The iCE40 parts are not so efficient for density. They provide bare minimums in many ways. Like no multipliers, 8 bit only memory and the bare minimum in the logic cells. So I'm not surprised they use more logic elements.
I ran Efinix up the customer flag pole. I'm not sure anyone is going to salute that either. Looking one more time at Digikey I found a Xilinx Spartan 7 part in a 196 BGA (1.0 mm) that had a bit of inventory with claimed more arriving in April. Mouser has inventory on a Lattice ECP5 part in a 256 pin BGA (0.8 mm). Both will require a separate flash memory. I think the Lattice part will accept an SPI flash. I don't know if Xilinx has relaxed their interfaces. Many years ago, it would only work with special Xilinx compatible flash parts.
In theory, I could push the responsibility for configuration back to the host motherboard. Someone else would have to write that code. But I'd have to set up my test fixtures to do the same thing. I plan to design a new test fixture for this, that would test eight UUTs at once. I'd like to use the same FPGA for both the new board and the test fixture.
asmi:
--- Quote from: gnuarm on January 06, 2023, 10:55:26 am --- I don't know if Xilinx has relaxed their interfaces. Many years ago, it would only work with special Xilinx compatible flash parts.
--- End quote ---
Oh man, you've got to look at a calendar and realize that it's 2023 now, not 2003 anymore :palm:
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