[Help with project] FPGA computer

[chilly moon]

Hiya! Been working on a little hobby project, am mostly a software dev, so I wanted to try out the hardware side of things mixed with my development, so I've been messing around with making my own CPU instruction set, and I had the idea to use a FPGA and make something with it. Am pretty new to the schematic/pcb stuff so hoping that people can guide me through this.

[Help with project] FBGA computer

I am already guessing a lot of what I got there is wrong

[stuck current]

It's hard to tell to be honest. The schematic is very hard to read so I can't say for sure

[chilly moon]

I can provide the files if need be

This correct?

[stuck current]

That's not the problem. The schematic itself is layed out not that well so it's hard to see where all the wires go. I was trying to look up a schematic layout video but I can't find it

[chilly moon]

Ah ye, still trying to learn how to properly do that

I am a bit more used to easyeda

[stuck current]

Well this doesn't really have anything to do with the editor tbh

[chilly moon]

fair

[stuck current]

The buck converters for example would be much easier to check if you drew them like this

[chilly moon]

noted

[stuck current]

And you can separate that power section into a hierarchical sheet for example so you have more space on your main page

And it would help a lot of ground symbols would always point downwards and power symbols upwards

[chilly moon]

Ah okay!

[Help with project] FPGA computer

[unreal spear]

Omg @tardy chasm here you can adopt another child 🤭

[chilly moon]

[unreal spear]

Chris loves fpgas verry much xD

[chilly moon]

oooo

I've ordered a dev board atm to try it out first before actually making a pcb XD

https://www.en.alinx.com/Product/FPGA-Development-Boards/Artix-7/AX7035B.html

is the one I ordered

seemed decent enough to try some stuff out on

[crude kite]

Your CFF caps are magnitudes too much capacitance

You are using a USB 3 port symbol when you really only need the basic USB 2 symbol

You have a.. 6 layer board?

I doubt you need that

Avoid routing anything on in1 as it should be a solid ground plane

Drop to 4 layers

Your inductors are certainly too large

Find a package that's smaller for them like XGL4040 or something from coil craft since I doubt you need more than 2A through any of those bucks

I agree with emiel you need to rework the schematic layout for the bucks and their symbols

Power symbols should always point up and ground symbols always point down

[kind latch]

I would suggest watching this https://www.youtube.com/live/ySuUZEjARPY and this https://www.youtube.com/watch?v=X0hd_v8qRiY a couple times through, you'll benefit a LOT from it, and also check out phils lab ;)

[chilly moon]

I see

[celest spire]

How good are normal FBGA's that they can output video for a hobbyist's Computer?

[crude kite]

i mean vga is pretty easy to do

an rp2040 or at least the 2350 can bit bang vga

[celest spire]

So I can control a rp2040 to drive the VGA persay

[crude kite]

https://youtu.be/wX1IPa3Q0LU

[celest spire]

I know that exists, and I know it's cool

[warm field]

https://youtu.be/X0hd_v8qRiY?si=lbJBf_V7om5efZBW

[warm field]

Oh just saw someone already sent this!

[warm field]

The power traces are WAY too thin.

[warm field]

I agree that those inductors you've got on there are WAY bigger than you need. Check this out to learn how to select them: https://www.ti.com/lit/an/snva038b/snva038b.pdf?ts=1769843838937

and like Salmon said, the CFF cap needs to be what the datasheet recommends. 22 uF is WAY too big.

[warm field]

You must observe the proper power supply sequencing; it's not acceptable for them to all come up together. This is not uncommon with parts that have multiple power rails.

Read here for more info (page 23, power supply sequencing: https://www.mouser.com/catalog/specsheets/Lattice_12-03-2025_Ice40.pdf?srsltid=AfmBOorByw7W360JFiBfjZIJFTAdf3Mwh5KY6J_J9zsN36R4j09J9cQ0)

I didn't go deeper because I found the schematic too hard to read.

[tardy chasm]

Layout isnt kosher either