Electronics > FPGA
XC7S15-1FTGB196C Unobtainium
nctnico:
--- Quote from: gnuarm on December 13, 2022, 06:27:52 am ---
--- Quote from: nctnico on December 13, 2022, 12:32:02 am ---
--- Quote from: gnuarm on December 12, 2022, 11:26:22 pm ---They have talked more than once about their ability to throw their weight around to get what they need. I can't even get samples.
--- End quote ---
Good luck with that. I've heard that story more than once but have not seen any parts appear out of thin air. The assembler I'm using also does a lot of work for a major supplier of electric distribution parts. It doesn't help. Heck, not even the major car manufacturers can get parts. All you do while waiting for Xilinx parts to appear is fooling around and wasting time wishing life is better. If you want to move products out of the door in this new world, then you need to adapt and get work done. The sooner you realise that, the sooner you can make money.
And no, EMC testing is not an issue where it comes to replacing a part that has zero incluence on EMC behaviour.
--- End quote ---
That's absurd. It's not the part that emits any real EMI, it's the board. To change the FPGA is a major redo of the board layout, likely with different power supplies as well. It would be up to me to certify that nothing significant changed, and there's no way I'm doing that. If they don't want to retest, that's their problem since it's in their product anyway.
But just to be clear, I won't have a choice. If they say no Gowin parts, I pick something else. So this discussion is of no value.
--- Quote ---A quick test at most and off you go. Unless ofcourse your layout guy is grossly incompetent.
--- End quote ---
I don't know what to say to you. That's not how EMI works.
--- Quote ---On top of that, a product that has been designed with replacing parts in mind at some point is much easier to modify later on compared to a design that is tightly knit together.
--- End quote ---
Tightly knit??? That's of no value in this discussion since you know nothing of the design.
--- End quote ---
Sorry, but these are really poor arguments. An FPGA is sitting somewhere on a circuit board. Typically surrounded by other compoments that deal with I/O and outside world signals. If you leave room on the board to use a different component, it is not much of a problem to switch to a different component. This is PCB design 101 and I have done that in several occasions. However, if you pack the components together so they are tightly knit together, you'll lose any flexibility to alter the design.
Where it comes to EMI: Typically you'll have at least a 4 layer board with a solid ground plane + power planes if you use an FPGA. Each signal to and from the FPGA can have an extremely small loop area because the return path (ground or power plane) is right under the trace. So unless you set the drive strength to maximum and/ or route traces over splits in a plane and/or have high speed signals going into external cables, it is safe to say that a different FPGA won't affect EMI in any way. One of the reasons FPGAs have adjustable drive strengths is to help reduce potential EMI issues. I'm not saying not to re-test but the re-test can be a very quick (and thus cheap) measurement. Nothing to sweat about there. From my experience you really need to screw up the PCB design of a board to make the board itself radiate too much. Where it comes to EMC compliance, wiring is way more problematic.
Power supplies is also straightforward. The FPGA you are after is not a super high-end device so currents are low. If you keep the power supplies close to the FPGA, you can replace these if necessary but likely you can keep the same ones set to slightly different voltages. Bonus points for designing the power supply solution with some flexibility in mind.
--- Quote ---You aren't making sense. Maybe you have not read the many reports of spying on networks by Huawei equipment?
--- End quote ---
This is borderline thin-foil hat conspiracy theorism. Explain how you'd go about spying through a low end FPGA in a random design? At some point you just have to be realistic about the actual risks.
gnuarm:
--- Quote from: nctnico on December 21, 2022, 07:53:49 pm ---
--- Quote from: gnuarm on December 13, 2022, 06:27:52 am ---
--- Quote from: nctnico on December 13, 2022, 12:32:02 am ---
--- Quote from: gnuarm on December 12, 2022, 11:26:22 pm ---They have talked more than once about their ability to throw their weight around to get what they need. I can't even get samples.
--- End quote ---
Good luck with that. I've heard that story more than once but have not seen any parts appear out of thin air. The assembler I'm using also does a lot of work for a major supplier of electric distribution parts. It doesn't help. Heck, not even the major car manufacturers can get parts. All you do while waiting for Xilinx parts to appear is fooling around and wasting time wishing life is better. If you want to move products out of the door in this new world, then you need to adapt and get work done. The sooner you realise that, the sooner you can make money.
And no, EMC testing is not an issue where it comes to replacing a part that has zero incluence on EMC behaviour.
--- End quote ---
That's absurd. It's not the part that emits any real EMI, it's the board. To change the FPGA is a major redo of the board layout, likely with different power supplies as well. It would be up to me to certify that nothing significant changed, and there's no way I'm doing that. If they don't want to retest, that's their problem since it's in their product anyway.
But just to be clear, I won't have a choice. If they say no Gowin parts, I pick something else. So this discussion is of no value.
--- Quote ---A quick test at most and off you go. Unless ofcourse your layout guy is grossly incompetent.
--- End quote ---
I don't know what to say to you. That's not how EMI works.
--- Quote ---On top of that, a product that has been designed with replacing parts in mind at some point is much easier to modify later on compared to a design that is tightly knit together.
--- End quote ---
Tightly knit??? That's of no value in this discussion since you know nothing of the design.
--- End quote ---
Sorry, but these are really poor arguments. An FPGA is sitting somewhere on a circuit board. Typically surrounded by other compoments that deal with I/O and outside world signals. If you leave room on the board to use a different component, it is not much of a problem to switch to a different component. This is PCB design 101 and I have done that in several occasions. However, if you pack the components together so they are tightly knit together, you'll lose any flexibility to alter the design.
--- End quote ---
You know nothing of the design, yet you insist that you can tell me how to make it work with multiple different parts.
Why are you like this?
I'm pretty sure I've explained that I can't replace the FPGA without the customer requiring retesting at several levels. In fact, that's exactly what we are doing now. Replacing the FPGA and a CODEC chip. This now requires the board to be recertified. YOUR experiences with YOUR customers is irrelevant to the matter.
--- Quote ---Where it comes to EMI: Typically you'll have at least a 4 layer board with a solid ground plane + power planes if you use an FPGA. Each signal to and from the FPGA can have an extremely small loop area because the return path (ground or power plane) is right under the trace. So unless you set the drive strength to maximum and/ or route traces over splits in a plane and/or have high speed signals going into external cables, it is safe to say that a different FPGA won't affect EMI in any way. One of the reasons FPGAs have adjustable drive strengths is to help reduce potential EMI issues. I'm not saying not to re-test but the re-test can be a very quick (and thus cheap) measurement. Nothing to sweat about there. From my experience you really need to screw up the PCB design of a board to make the board itself radiate too much. Where it comes to EMC compliance, wiring is way more problematic.
--- End quote ---
You are an engineer and seem to be only capable of thinking like an engineer. The issues involved are simply that the traces on the board have changed. NO ONE, including YOU, can say for certain that small changes in the routing won't alter the emissions enough to no longer be in compliance.
--- Quote ---Power supplies is also straightforward. The FPGA you are after is not a super high-end device so currents are low. If you keep the power supplies close to the FPGA, you can replace these if necessary but likely you can keep the same ones set to slightly different voltages. Bonus points for designing the power supply solution with some flexibility in mind.
--- Quote ---You aren't making sense. Maybe you have not read the many reports of spying on networks by Huawei equipment?
--- End quote ---
This is borderline thin-foil hat conspiracy theorism. Explain how you'd go about spying through a low end FPGA in a random design? At some point you just have to be realistic about the actual risks.
--- End quote ---
Again, this is something you know nothing about. There are experts in the field who know what can, and has been done in devices from China.
Why do you keep talking as if you know things, that you clearly don't?
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