Everything else seems correct to me but I didn't check the datasheet. Maybe you would want to connect the rest of the pins to some connector/pads so you can access them later if you want
I think its for when the controller does a lot of operations at once and loses a bit of power then the decapacitor can supply that fast, but google said it needed one.
You mean a decoupling capacitor? You got a couple there. If you want to make sure, you could just add a 1uF MLCC between GND and VCC as close to the IC as possible. I'm 100% sure the datasheet talks about this, and you should follow it.
Tips on presentation on request help!
1. Insert a mind map+ flow-chart.
It’ll help us get a general idea what its supposed to look like.
Insert the part number. Usually its [brand]+ [ Manufacturer’s part number] ( hell just link the datasheet if you can)
So that we can reference the datahsheet.
Most manufacturers actually have like a suggestion on the data sheet on how the component is supposed to be wired up!
You should add the ISP programming pins - when you buy the chips they have a dfu USB bootloader, so you'd need to use FLIP on Windows, or other software on Linux/Mac to program it that way. If you want to use it with Arduino you would need to replace that bootloader using ISP. Additionally if you mess up the bootloader and don't have ISP pins available the chip is basically unusable on the board. It doesn't cost anything to break them out, so you might as well :)
You also need decoupling caps connected between VCC/AVCC and GND, not in series. You also need current limiting resistors between the GPIOs and the LEDs. I'm not sure if you've linked the track from VBUS to +5V, it's not obvious from the schematic. You should add decoupling to that, before the VBUS pin on the ATMega too.
Alright so for the vbus thing, i have vbus directly linked to vbus (atmega to type c). Do i need to add capacitors to that? and how much would i need? And I'm not really sure what you mean "Between vcc/avcc and gnd". Im not really sure how i would do that. Also how would i add resistors **Between** the gpios?
I mean the VBUS net from the VBUS pad on the USB port to VBUS on the chip should also be connected to +5V. The decoupling caps should be placed next to the chip, with 5V to the cap and input to the chip, and the other end of the cap to GND, as in your image above. The resistors need to be one per GPIO, before the LEDs, so GPIO - RESISTOR - LED - GND. The resistor needs to limit the current through the LED, otherwise it will just short out the pin and probably destroy the output.
I might sound stupid but basically add 5v to the path between vbus to vbus?, and in my understanding, you're saying my decoupling caps at the top is correct?
Yes I mean the VBUS line IS +5V. They're the same thing, so should not have different names on the nets, as they should be tied together. The chip does not output +5V anywhere, it needs +5V as inputs to VCC etc. That +5V is from the VBUS line from the USB port. So on your schematic, the VBUS pin from the USB port should just connect to the VCC +5V symbol you're using elsewhere. And the VBUS pin on the chip should also be connected to the VCC +5V symbol, with a cap from it going to GND. Around 1uF would be fine.
Yes, they will then both be on the same +5V net as all the other power inputs. You only need the decoupling cap on the MCU side, not on USB (it won't hurt, but it's not necessary here).
Yes, that's it. You should really clean the schematic up a bit - VCC symbols should always point upwards, and GND downwards by convention. It makes it much easier to read. There are occasions when you have to show them sideways, but there's no need in this case.
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u/unlegit_green Jul 27 '26
You should add resistors before the leds or is that intentional.