Schematic Info

[User5717]

On the schematic for the Arty S7-50 there is a VCC1V8 going to VCCAUX as shown below.

 

What is the purpose of VCCAUX? Some documentation I've read on the board label it as 1.8V power supply for auxiliary circuits as shown below.

 

Does auxiliary circuitry imply internal to the FPGA?

Is this voltage to VCCAUX needed for the FPGA functionality?

Can this pin be used via a 3.3V or 1.0V supply?

 

This is my first time designing a custom PCB which is why I am wondering if these voltages are necessary.

Thank you! 

[zygot]

55 minutes ago, User5717 said:

This is my first time designing a custom PCB which is why I am wondering if these voltages are necessary.

Tip: Don't solicit random responses to questions about PCB design questions if you are new at this, and hoping that someone answers questions that you haven't thought of. Also don't copy someone else's designs. Do read any literature that you can get a hold of regarding board design considerations from device vendors. There's plenty available and you should not restrict your search to one vendors. Do you homework before starting a PCB design not after trying to bring up new boards that are having problems. The first topic on your list would be power supplies.

Edited June 28, 2021 by zygot

[User5717]

13 minutes ago, zygot said:

Tip: Don't solicit random responses to questions about PCB design questions if you are new at this, and hoping that someone answers questions that you haven't thought of. Also don't copy someone else's designs. Do read any literature that you can get a hold of regarding board design considerations from device vendors. There's plenty available and you should not restrict your search to one vendors. Do you homework before starting a PCB design not after trying to bring up new boards that are having problems. The first topic on your list would be power supplies.

Thank you for your "tip", let me clarify. I am not copying designs, I pasted an image to show as reference.. The question is simply regarding the VCCAUX on the schematic and what purpose it serves for the FPGA.

I did not ask specific questions regarding PCBs. Please consider questions rather than comments first. 

[zygot]

My intention was not to offend you, but to steer you in the right direction. The proper place to get an answer to your question(s) is from FPGA vendor documentation... not here. But feel free to take your chances if my advice doesn't appeal to you. No one should feel obligated to abide my comments, nor feel offended by them. You asked a question, I replied with my best answer, to the extent that I understood your question, which was pretty open-ended and non-specific. Nothing in my previous reply implies anything negative about you personally. I really don't understand why you are miffed at the response.

1 hour ago, User5717 said:

Please consider questions rather than comments first.

What questions are you looking for? Perhaps reading the vendor material will generate more specific questions.

What specific part of my previous reply do you think is in error? No other questions come to mind.

 

Edited June 28, 2021 by zygot

[JColvin]

Hi @User5717,

I don't have a whole lot to add outside of that it's an auxiliary supply voltage.

As @zygot mentioned though the vendor documentation on Vccaux will be the most helpful to you in this regard; specifically DS189, UG483, and this Xilinx Answer Record I found after a bit of searching.

To answer your specific question though, you cannot use that pin with a 1.0V or 3.3V supply, as per the Xilinx documentation.

Thanks,
JColvin