I'm not sure why you position things as if it's either KiCAD or breadboards. Whenever I've designed a PCB, I've gone from breadboard, to schematic, to PCB (the last two in KiCAD). The breadboard is a necessary first step to make sure that the circuit works in the real world, not just in theory.
These days, with $5/sq-inch 2 layer boards and cheap prices for 4 or 6 layer boards... This makes 40+ pin microcontrollers and 200+ pin BGAs even are well within the means of a modern Hobbyist today in 2023. But there is no hope for these chips to ever be adequately placed on a breadboard.
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From my experience, breadboards and protoboards are for simpler learning projects. But you rather quickly grow beyond what a breadboard can offer.
Breadboard when you are at breadboarding level. But once you graduate to greater levels of complexity, you can only buy custom pcbs (and possibly 4 or even 6 layers at that). It's literally impossible to breakout a full square ~17x17 pin BGA on 4 layers, let alone dealing with EMI or signal integrity effects.
That's true, I guess my designs are rather more basic than that. I never managed to figure out how to work with these slightly more complicated chips, though I'd like to.
Start with a 32-pin beginner uC like STM32G0, AVR64DD32 (more modern version of AtMega328pb), PIC, or other such chip.
Find a useful sensor to some itch you have: temperature, pressure, weight, time, CO2, accelerometer, whatever is interesting to you. Make a design that reads the sensor and writes it to LEDs (red is bad, green is good), or 7-seg displays, screens or some other visual device.
Order 3 or 4 boards, low temperature lead free solder paste, no clean flux (bullshit, you should clean it off), solder wick, cheap isopropyl alcohol to clean the flux after the fact, a pancake grill, and 3 or 4 copies of all the chips you need.
If you stick with larger surface mount chips like 0805 inches or 2012 (metric), a soldering iron is sufficient for rework. Smaller chips require a hot air gun.
Try to stick with larger chips like SSOP or even SOIC chips. TQFP should be doable with the sloppy then flux+solder wick cleanup method but don't go any smaller as a beginner. SOT-23 is easy.
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Mess up your first attempt. That's fine, you have 2x more tries.
Build it successfully using pancake griddle reflow method (solder paste on the pads, be sloppy if you must. Place enough so all the components stick to the gel-like solder paste in place. Heat to 350F or 138C for low-temp solder paste (you can tell because it liquefies and all the components start floating).
Use a toothpick to push items back into place, turn off heat. When cool, use lots of flux, solder wick + solder iron to fix bridges (should be super easy. If it's not easy, use more flux and try again and/or buy new solder flux+wick. That stuff goes bad every 2 months).
Done. Except you probably made a mistake on your schematic. Fix that, order new parts, try again and be happy the time it finally works.
Keep your flux, wick, and solder paste refreshed (throw out old consumables, buy new every few months) and you should be good to go.
Order a x10 jewelers loupe or x15 or x25 to visually inspect these solder joints. If all looks well, grab your fire extinguisher and turn on your electronics project! Best of luck.
Thanks for this! I've already soldered and designed a lot, I just don't know how to find the microcontrollers' "boilerplate" (eg all the pull-ups and pull-downs it needs to boot, capacitors, stuff like that). It also doesn't help that my C isn't great, but I guess I can write Rust on the STM32 nowadays.
This is about a YouTube video that walks through a reference design for an STM32F1, a beginner friendly chip with very simple startup.
You only need the 100nF capacitors as indicated in the reference documents, but the video also adds a Ferrite Bead + Pi filter (1uF + Ferrite + 1uF), which is considered a good practice to reduce noise... but likely is optional and not needed at a beginner level.
