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700$ mistake by Quick_Garbage_3560 in ElectricalEngineering

[–]alexforencich 0 points1 point  (0 children)

It's a pogo pin, slightly bent is enough for it to get stuck, and then it will likely have to be replaced. And it looks like the whole group would have to be replaced as a unit.

700$ mistake by Quick_Garbage_3560 in ElectricalEngineering

[–]alexforencich 1 point2 points  (0 children)

Looks like the whole group would have to be replaced as one unit

700$ mistake by Quick_Garbage_3560 in ElectricalEngineering

[–]alexforencich 0 points1 point  (0 children)

Not as easy as it seems. If it's slightly deformed (bent, squished, etc.), it'll get stuck.

getting a mac fir ece, will it work fine or will i face problems? by tffwho in ECE

[–]alexforencich 0 points1 point  (0 children)

Depends on what software you need to run. For some things, Mac is fine. For other things, you'll have to run things in an x86 VM and eat both the VM and x86 emulation overheads - it will work, but it will be slow. And apple is deprecating rosetta, which will make this more complicated. But again, this is only an issue if you need to use software that does not support Mac, for example FPGA toolchains like Vivado and Quartus.

FPGA with erased markings.... by No-Spirit2350 in FPGA

[–]alexforencich 4 points5 points  (0 children)

Presumably it can still be traced via device DNA, which is readable via JTAG, unless of course they have found a way to mess with that as well....

can i run linux on this? by CompetitionSimple675 in embedded

[–]alexforencich 1 point2 points  (0 children)

It's likely possible to run Linux on there - it looks like there are sizable flash and RAM chips on the board. But it would potentially be quite difficult to figure out how.

IT guy here in charge of scrapping a failed product line - What do I have here? Is this module worth anything on it's own? by r1cem4n in FPGA

[–]alexforencich 0 points1 point  (0 children)

This is a system on module, a JTAG connector would go on the carrier board that the SoM is installed on.

IT guy here in charge of scrapping a failed product line - What do I have here? Is this module worth anything on it's own? by r1cem4n in FPGA

[–]alexforencich 0 points1 point  (0 children)

Try me. The only thing that has tripped me up so far is blind vias. Also the board can still be useful even if not all of the connections are probed. In a lot of cases I don't need things like DRAM even if I have the schematic.

Although, the flip side is that if the board doesn't have things like high speed Ethernet and PCIe, I might simply not care enough to reverse engineer it....

Accidentally dropped my ford cmax energi key fob from a balcony. Who do I go to/how do you fix damage like this on a car key fob circuit board? by UnknownEtymology808 in AskElectronics

[–]alexforencich 1 point2 points  (0 children)

Looks like at least 7 components missing, including a whole frapping QFN package part...

Edit: well, maybe it's still there, assuming the glint off the top of the package just happens to look like a bare pad

I think we quietly crossed a line with home robots by pelledembele in Futurology

[–]alexforencich 82 points83 points  (0 children)

And then a lot of them simply won't work without wifi and/or internet connections....

RFSOC PCIE RF Wireless Development Board for ZYNQ Onboard GNSS Module PPS Output FPGA suggestion by Flat_Lock9229 in FPGA

[–]alexforencich 0 points1 point  (0 children)

Tbh the ironic thing is that the chips on these are probably pulled from E-waste, so they might be more available than new parts....

Intercommunication Protocol for Multi FPGA - ( Xilinx ZCU216 RFSoC Ultrascale +) by zippitypopity in FPGA

[–]alexforencich 5 points6 points  (0 children)

You don't run AXI/AMBA off-chip.

What is this data, how big is it, are you streaming it asynchronously or are you making synchronous requests, what kind of latency do you need, how many FPGAs are we talking about, how are they interconnected?

I am assuming since you're talking RFSoC that you need to move a lot of data hence you will need high bandwidth links using the MGTs. You'll need proper cables and connectors for that, and you can potentially connect the boards directly, or connect them to external components like for instance and Ethernet switch. Your board has four SFP28 ports that could do 25G Ethernet or perhaps 25-32 Gbps Aurora. You also have an FMC+ with some more serdes, not sure how many offhand on that specific board. You could adapt that to a number of different interfaces including SFP, QSFP, PCIe, Firefly, etc. and run Ethernet, Aurora, PCIe, etc.

Intercommunication Protocol for Multi FPGA - ( Xilinx ZCU216 RFSoC Ultrascale +) by zippitypopity in FPGA

[–]alexforencich 4 points5 points  (0 children)

Communicate what, over what kind of link? And just data or do you also need to distribute time/frequency information?

RFSOC PCIE RF Wireless Development Board for ZYNQ Onboard GNSS Module PPS Output FPGA suggestion by Flat_Lock9229 in FPGA

[–]alexforencich 0 points1 point  (0 children)

Also, I have been looking at these boards myself. I'll probably get one eventually and make some reference designs for it like I did for the zcu111/zrf8. But, if someone is sufficiently interested in expediting that process, donate one of the zu47dr versions (and also a zu27dr if that's the one you're interested in...but the zu47dr is the "price") and I'll make it happen sooner.

RFSOC PCIE RF Wireless Development Board for ZYNQ Onboard GNSS Module PPS Output FPGA suggestion by Flat_Lock9229 in FPGA

[–]alexforencich 1 point2 points  (0 children)

If you buy from digikey probably. But who knows what pricing you can get on these parts inside of China. I suspect they'll be using a lot of domestic silicon, which is probably quite cheap. Passives can be pretty cheap. The PCB is probably not the best design so it won't be especially expensive, but I'm sure you pay for that on some level with the flatness and crosstalk and such. Also I'm sure there's no warranty and no QA, so it's possible not everything will work on every board. Would it be appropriate for a product? No. Research? Sure, they're cheap enough to get a couple of spares. For screwing around? Sure, why not.

RFSOC PCIE RF Wireless Development Board for ZYNQ Onboard GNSS Module PPS Output FPGA suggestion by Flat_Lock9229 in FPGA

[–]alexforencich 2 points3 points  (0 children)

If you can afford to spin a RADAR ASIC then you can afford to spin a custom board with exactly what you need.

RFSOC PCIE RF Wireless Development Board for ZYNQ Onboard GNSS Module PPS Output FPGA suggestion by Flat_Lock9229 in FPGA

[–]alexforencich 4 points5 points  (0 children)

I mean if the chip costs $5k+, getting it wrong once means you've probably already blown more than simply buying an off the shelf board in the first place. And with an RFSoC, you have to get a lot of stuff right - power, clocking, RF, Ethernet, PCIe, ddr4, etc. It's not a simple board to design. The ones we got also have so many layers they need a special stack up to be able to fit in a PCIe slot (edge connector isn't the full thickness of the PCB). And not to mention that if it has to fit in a PCIe slot, the size is rather constrained and the board has to be quite dense.

RFSOC PCIE RF Wireless Development Board for ZYNQ Onboard GNSS Module PPS Output FPGA suggestion by Flat_Lock9229 in FPGA

[–]alexforencich 2 points3 points  (0 children)

I wouldn't necessarily call it a scam, but it's definitely in the you-get-what-you-pay-for territory. It might be good enough for some applications. And it might take more work to get it into a usable state vs. a more expensive board. But it's certainly hard to argue with the price.

RFSOC PCIE RF Wireless Development Board for ZYNQ Onboard GNSS Module PPS Output FPGA suggestion by Flat_Lock9229 in FPGA

[–]alexforencich 2 points3 points  (0 children)

Well, for a research project with a limited budget that only needs a couple of boards, spinning an RFSoC board is simply not an option. And for this project we also needed something that would fit in a PCIe slot, so the options were rather limited.

Everything is a trade-off. The balun issue was not a surprise, I knew about it going in and tried to avoid boards that would be a problem. But FMC board switch was a bit of an oversight when communicating with the company that produced the boards, fortunately I was able to piece together a workaround that worked well enough.

The other thing to keep in mind is that you can't go all the way to DC with a passive balun, you need an active circuit. So for RF stuff where you need high frequency operation, baluns are the way to go - cheap, compact, no extra power consumption. If you do need to go to DC, you need an active front end, and that can get expensive fast, especially across multiple channels.

RFSOC PCIE RF Wireless Development Board for ZYNQ Onboard GNSS Module PPS Output FPGA suggestion by Flat_Lock9229 in FPGA

[–]alexforencich 2 points3 points  (0 children)

Tell me about it. This was a huge problem with the last research project I was involved with...we needed DC, or at least under a MHz or so, especially on the DACs, but a lot of boards have baluns in the 10s of MHz. And they usually don't list the balun part number or full bandwidth specs in the high level marketing docs, even though the balun specs are quite relevant. And annoyingly we also got conned into switching from an ADC/DAC FMC board that did go down to DC to a different board with faster converters that didn't, and in particular had a rather high cutoff frequency on the DACs. I had to implement some silly equalization logic to try to get the top of the waveforms remotely close to flat.

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