Small Design Help - Page 1
Forum section: electronics / projects

author: xD90o1
author_rank: Newbie
timestamp: April 26, 2018, 01:05:46 pm
content: Hello. I'm still a bit new in making my designs but I already know how to do so. I want to ask you guys for some improvements and some errors I should correct in my design so that if I finally had the board manufactured and all the components assembled, it won't end up as a fail. I may or may not sell one of these designs of mine (bonus points to those who can guess which one I will) because of some things I can't really explain lolInside the zip files in my attachments are the pdf of my schematic and 3D view images of what the board will look like.

author: Benta
author_rank: Super Contributor
timestamp: April 26, 2018, 01:25:29 pm
content: I don't open ZIP files. Just post the PDFs.

author: xD90o1
author_rank: Newbie
timestamp: April 26, 2018, 01:28:58 pm
content: Quote from: Benta on April 26, 2018, 01:25:29 pmApologies. Here are the PDFs out of their zipped folders

author: Rerouter
author_rank: Super Contributor
timestamp: April 26, 2018, 01:33:29 pm
content: At a glance, my first point would be, for any pads that will have larger wires soldered to them, staple them with a grid of via's to the other side inside the pad, it will make it much harder to tear the pads off (In my experience I have had boards snap before pads tore when I do this)Your using Kicad, for future products, I would suggest setting the paper size bigger, spacing out things nicer and using net names so its easier to know what the function of each trace is as you route it, but thats just procedural recommendations. (your schematic is kinda hard to read due to how cluttered it is)Your crystal wires look kinda long, and routed around other less important stuff, If you can try and group that up nice and tight so no digital logic crosses your crystal.No external pullup on your reset pin in a high noise enviroment is kinda asking for trouble.For your motor drivers, consider what happens when your microcontroller is in a reset state, e.g. programming, all pins become inputs with pullups, if this causes unwanted behaviour you may want to add pulldowns to pins that must stay low.The other recommendation I would add is make clear what your input voltage range is right next to the supply wires, It will prevent dumb errors,

author: xD90o1
author_rank: Newbie
timestamp: April 28, 2018, 01:22:14 pm
content: Thanks for the recommendations. I'll have it improved sometime

author: Sarcarean
author_rank: Contributor
timestamp: April 28, 2018, 10:52:56 pm
content: It might be your rendering, but are your via's too small? I would think that a lot of the traces expected to move more current would have much wider vias to compensate for the loss in conductive area.And for your oscillator, I would keep it on the same side of the IC without using a via to go under the board. In my experience, the most problems I have had with designs like this is the clock placement. You want to keep it as close to pin 5 and 6 as possible. And also, I see you do not have any caps either. This is a crystal? I would expect to see 18pF to 20pF.

author: xD90o1
author_rank: Newbie
timestamp: April 29, 2018, 04:25:13 am
content: Quote from: Sarcarean on April 28, 2018, 10:52:56 pmFrom what I found in other flight controllers, The Naze32, SP F3, as well as some other F4 ones, they put their osci under the board but just well near the osc in and osc out pins of the MCU so I'm safe to say that I'm on the green with me putting my osci under the board too. But maybe on my F7 design, I'll have to put it on the same side with the MCU and near the osc in and out pins of it. I might also have to use dual IMU in my F7 design somewhere on the lines of using an MPU-6000 and an ICM-20689 or maybe an MPU-6500 and ICM-20608 duo