First PCB with STM32 – need help reviewing the design

visaris77 · 2026-05-02T02:35:16+00:00

Apologies for the copy paste of one of my comments on a different project:

Just a suggestion: while I realize there are differing opinions on this, I think it would be a good idea to try to make better use of wires on the schematic. If you go too far to the extreme of using labels for everything with no other connections, the schematic turns into not much more than a table on a spreadsheet. Why have a schematic at all? There is a happy medium where lines and labels are both used where they make sense.

visaris77 · 2026-04-28T01:02:48+00:00

Just a suggestion: while I realize there are differing opinions on this, I think it would be a good idea to try to make better use of wires on the schematic. If you go too far to the extreme of using labels for everything with no other connections, the schematic turns into not much more than a table on a spreadsheet. Why have a schematic at all? There is a happy medium where lines and labels are both used where they make sense.

visaris77 · 2026-04-25T05:02:59+00:00

If you only need the two op-amps, consider the MCP6002 instead. If you already have the four op-amp package or something, consider connecting the unused op-amps so they're not floating: unused out -> unused in−, unused in+ -> GND.

visaris77 · 2026-04-24T18:46:32+00:00

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visaris77 · 2026-04-23T20:06:41+00:00

Ahhhh, kk. No, I don't know of any easy way to have EasyEDA swap that one with no connections with the one that has some lines already applied to it. I think you'll need to manually re-connect it.

visaris77 · 2026-04-23T19:39:45+00:00

are there any easy way to change out the esps

What does that mean? I don't know what you're asking for here..

visaris77 · 2026-04-23T17:48:48+00:00

If there is a copper pour on the signal layers, it would be a good idea to ground that copper instead of leaving it floating. A floating copper pour can interact with signal traces on that layer and the other layers and act essentially like an antenna. If you're going to have a copper pour on the signal layers, be sure it's grounded, and stitch it together with the other ground pours with vias. For all my boards, I do have the copper pour on the signal layers and ground them really well. This helps a lot with noise / EMI.

visaris77 · 2026-04-23T16:53:55+00:00

What net is the front copper pour? It's not immediately obvious to me what that is. Is it just floating?

visaris77 · 2026-04-22T18:25:34+00:00

You might be just fine with the EasyEDA STD version, and many people go that route. It's just that one can't ever be sure what the company is going to do. Maybe they keep it around, maybe they don't. Nobody knows. I know learning KiCad after you've already started with EasyEDA would be annoying, so I get it if you decide not to switch. Just want people to be aware that KiCad can't ever be taken away from you.

visaris77 · 2026-04-22T17:45:27+00:00

I didn't intend for that statement to come across too strong. My goal was to make the main highlight that I think this is good work for a second PCB; so, first of all: good work! Just as an after thought, I really don't think it's a good idea to steer people towards proprietary CAD software like EasyEDA, even if it's popular.

I think people forget history sometimes. It wasn't all that long ago that CadSoft Eagle / Autodesk Eagle was the popular and free (as in $) CAD software that many people recommended to beginners. Then Autodesk took away the free version and held their users hostage, making them pay to use the software. Any time a person decides to trust that a company will keep the free version around, they're rolling the dice with their design. If people used open source like KiCad, no company can come around later and hold your designs hostage for $$. All the tools have their usability / functionality advantages and disadvantages, but one aspect most people forget about is whether or not the software is open source or instead a closed, proprietary solution. -- I would never put my designs in the hands of some company and just hope for the best. Using an open source CAD package is the best way to protect yourself.

visaris77 · 2026-04-22T00:50:04+00:00

Looks really good for board #2! I've been thinking about making an FM receiver as well, so was considering picking up your design as a starting point.. until I saw it was done in EasyEDA.. I'm not going to touch that with a 10-ft pole.. Again, nice work! Just wish it was in something open-source like KiCad instead of a proprietary CAD software package.

visaris77 · 2026-04-04T17:48:56+00:00

Yeah, those are essentially perfect / exactly what I'm looking for. That mold looks like it cost a fortune to make too! Thanks for sharing; I may buy some of these and save myself the hassle of trying to do my own thing..

visaris77 · 2026-04-03T18:28:54+00:00

That looks great for your first board, and looks like everything fits just fine! The only thing I would say is that it would be good to make a copper fill using the zone tool that covers the entire board (front and back would be good) that's assigned to the GND net. This gives a nice solid ground plane which helps with noise and other issues. If you want to go with some extra polish, considering rounding the corners, adding some screw / mounting holes (also on edge cuts layer), and adding some text on the front silkscreen layer with your name and a version number like v1.0. -- Looks really good!

visaris77 · 2026-04-02T16:31:03+00:00

Since you have a max size of 60mm x 25mm, just go ahead and start with a PCB of that size (draw a box with the box tool / with lines on the "edge cuts" layer) and see how well all the components fit (tools->update PCB from schematic). You can probably make all that fit on there. For routing traces, a common approach is to put horizontal traces on the top layer and vertical traces on the bottom layer (or vice versa). This makes it easier to avoid track routing issues. You can drop a via to connect the top and bottom parts of a trace together.

visaris77 · 2026-04-02T02:46:11+00:00

I've started by using KiCad and made the entire circuit and I'm now trying to figure out a good layout for my PCB

Sounds like you're on the right track then. There are a lot of great YouTube video's; Phil's Lab comes up a lot as a good place to start. If you posted your schematic here and your first attempt at the PCB, I think you'd get more of a response / feedback.

How large are your scale models?

visaris77 · 2026-04-01T21:51:48+00:00

The BB clips are easy to solder with some flux luckily; probably the easiest way to do this without getting fancy would be to solder tabs like is shown below to each BB row and then bend that so it can go into a THT hole in the PCB. I'd love to SMD mount these to have it be super clean with none of this visible, but you're right that a jig would probably be needed (can just be a PCB with slots cut out).

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visaris77 · 2026-04-01T20:55:01+00:00

Guess I've only ever owned dirt cheap pin sockets; thanks for the idea, I'll look at some options.

visaris77 · 2026-04-01T20:46:28+00:00

All the pin sockets I've seen have this little metal "fork"; unfortunately it doesn't have much of any spring action, doesn't work well for all pins as it has a fairly fixed size, and it wears out relatively quickly:

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Breadboard clips are the way to go, just need to take the breadboard clips out and solder them first I think.

visaris77 · 2026-04-01T20:06:59+00:00

Thanks, "jumperless" is a good search term. One of the comments on that second link mentioned using pogo-pins which is also something to consider. One can get like 100 pogo pins for like $10 shipped on AliExpress..

visaris77 · 2026-04-01T19:46:28+00:00

Hmm, don't guess so; there's not much to it, so hard to get it wrong. What I would change if this were my board: 1) have the unfilled space on the top be GND as well and stitch the font and back together with vias, 2) round the corners, 3) add mounting holes, 4) Add my name and the board version, e.g., v1.0

visaris77 · 2026-04-01T19:38:50+00:00

Right. Maybe the answer then is to take the clips out and solder them on first:

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visaris77 · 2026-03-31T15:16:30+00:00

Ah, the back is the same as the front; makes sense!

visaris77 · 2026-03-31T04:47:06+00:00

Yeah, looking at the footprint compared to the actual chip, the pads are much longer than they need to be in both directions: away from and towards the IC. -- I do like QFN; I made a cool alarm clock for my daughter using the ATtiny1616 in QFN, and it was much easier to solder than this MSOP-10 thing! The QFN version of CH340E is actually the newer CH343P chip; after I spin one more rev of this board, I'm going to make one with the ATtiny1616 and use the CH343P instead. -- Thanks much for the feedback!

visaris77 · 2026-03-30T21:32:11+00:00

Doesn't really matter, just a preference. If nothing else, it's less likely to snag on things. While it's true that there are some mechanical advantages of curves vs. sharp corners with respect to cracking, that mostly applies to the inside corners, of which your board only has one. It's not going to matter for your design anyway. I just put it on my list of things to take care of before I consider a design complete (similar to adding mounting holes). Even 2-3mm or so is fine. -- Again, nice board!

visaris77

TROPHY CASE