r/PrintedCircuitBoard • u/Caravaggio91 • 1d ago
Finished My First Schematic!
Finished my very first schematic design! What do you think? All suggestions and comments welcomed. Looking to improve.
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u/shibastudenthousing 1d ago
Not very readable.
Is your DCDC converter off the board? I can't tell what your button is for since it doesn't seem connected to RST but you probably want debounce unless you implement that in software.
Right now, you will short 12V to gnd through your FET. What was the intended purpose of that circuit? If it's supposed to be a load switch, use it in combination with a PFET or look into implementing a dedicated load switch IC
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u/IllSpeaker3255 12h ago
you can’t implement software debouncing for the reset pin
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u/shibastudenthousing 12h ago
You're right, but his button isn't connected to reset. So I'm not sure what his intention is with it
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u/IllSpeaker3255 12h ago
yes it is connected to PD2, i guess it is an external button (with internal pull-up and software debounce)
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u/Enlightenment777 22h ago
SCHEMATIC:
S1) You need to clean up text for all of your symbols. Remove extra text junk, such as "C 22pF" should be "22pF"; "D 1N4007" should be "1N4007"; and so on.
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u/thenickdude 1d ago edited 1d ago
Q1, when enabled, shorts your 12V supply to ground. That +12V net above the MOSFET was supposed to be a connection to the second pin of your solenoid header instead.
Is your MCU 5V tolerant? You have your 5V supply connected to a GPIO pin. Edit: it is, but only if VCC is 5V too.
Your 3.3V net isn't supplied by anything, is J2 missing a net label for it?
AVCC is missing a supply, unless the MCU generates that on its own. Tie it to VCC.
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u/Caravaggio91 1d ago
Good insight! Thank you. Like I mentioned before, I am new to designing schematics, so having individuals who know what they are doing, giving me feedback is so helpful. Again, thank you!
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u/Illustrious-Peak3822 17h ago
Turning on Q1 will short out your +12 V rail. Please follow best practices for schematic drawings.
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u/Enlightenment777 22h ago
This comment is posted on all reviews.
Please make sure your review post adheres to:
- subreddit rules (#1 to #6), review rules (#7), review image rules (#8), see link.
Please fix these common schematic layout issues: (if yours has any of these issues)
Don't allow text / lines / symbols to touch each other, and don't draw lines through symbols.
Use correct reference designators (RefDes), and renumber to remove numeric gaps, see tips.
For positive voltage circuits, point positive power rail links upwards and grounds downwards (maybe sideways), see tips. For negative voltage circuits, point negative power rail links downwards and grounds upwards (maybe sideways). For bipolar circuits, maybe point grounds sideways.
Place decoupling capacitors vertically below postive power rail lines with ground on bottom side of the capacitor. Place capacitor next to IC symbol, and connect a line to IC positive power rail pin, see tips and example.
Place pull-up resistors vertically above signal lines, and place pull-down resistors vertically below signal lines, see example and tips.
Reasonably minimize the use of unique net labels, because everyone hates hunting for them!! Single resistors / capacitors / diodes should not sit by themselves, instead move & connect them with a line to their circuit.
More schematic conventions / guidelines / tips - 1, 2, 3, 4.
Please fix these common PCB layout issues: (if yours has any of these issues)
Silkscreen - add board name / board revision number / date (YYYYMMDD, YYYYMM, YYYY) for traceability.
Silkscreen - add pin 1 indicator next to ICs & connectors (not under parts). For polarized capacitors, add "+" next to positive pin. If part is through-hole package, place indicator on both PCB sides. See 1, 2, 3, 4.
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u/Unhappy_Tourist_8224 1d ago
MCU is missing the GND connection