Hi everyone,
Could someone correct my errors on the standalone shemat?
This has an atmega 64A and an atmega16U2.
thank you in advance 
What is H1 and why does UCAP lead there? Where are your processor supply bypass capacitors? Why 18pF caps on one crystal, and 22pF on the other? Wouldn't the BOM be cleaner with just four of the same value? I have to check, but don't you need an RC on the POR circuits?
Does the Mega64A do anything besides flash some LEDs? It's not connected to anything else.
Where are your processor supply bypass capacitors?
What and where do I put it ??
I have followed shemat on the internet and I have not seen??
H1: male pin 15x2
I corrected some thing so that you understand.
atmega64A will generate vga signal.
I am going to put the connectors afterwards
Image : 1 hosted at ImgBB — ImgBB
Why 18pF caps on one crystal, and 22pF on the other?
I correct immediately
(that's a stupid mistake)
Each and Every pin named VCC and AVCC needs a 0.1uF cap from the pin to Gnd.
If you ever plan to do any analogRead() then also put a 0.1uF cap from ARef to Gnd. DO NOT connect ARef to 5V.
Reset pins need a 10K pullup to 5V, you seem to have them connected to Gnd.
How do you plan to install a bootloader, set the fuses, and load code into the chips?
Reset pins need a 10K pullup to 5V, you seem to have them connected to Gnd.
Stupid error, i correct
If you ever plan to do any analogRead() then also put a 0.1uF cap from ARef to Gnd.
I did not know, i correct
0.1uF at each pin or for all pins
(0.1uF, Is it low ?? what is it for)
0.1uF at each pin or for all pins
(0.1uF, Is it low ?? what is it for)
You have a great deal to learn, so don't expect your efforts to be successful. Why are you doing this?
At the very least, study a bunch of professionally designed circuits using those chips. Pololu, Adafruit and Sparkfun post schematics of their products, and every single component is there for a good reason.
Much better: buy a development board that has the parts you actually need.
Each VCC and AVCC pin. They are like little energy reserves to the chip for when the internal transistors change state. They can react quickly, while the big 1uF and 10uF caps on the power supply lines help with any large current surges.
Read this
"You go kid !"
FYI, sloppy schematic capture work. You shouldn't have traces running across in front of a chip.
Also, you have no business designing a circuit without reading the datasheet.
You have a clipboard (preferably physical) but if not then virtual list of all the pins.
You said the miss-wire of the RESET was a "stupid mistake". Be that as it may (though I don't believe it) it is a clear
indication of a complete absents of a design process..
Although this is an exageration but it's like landing an airliner with the gear up and saying "stupid mistake !"
It would never happen because they have prelanding checklists .
You have a checklist of each pin and wire them one by one
from the checklist instead of just going crazy and wiring it all up in a mess.
Get your act together and post a schematic that looks well thought out and professional.
FYI, you may not be aware of it, but you are allowed to substitute node labels for actual traces so it reads:
"To U2-34 [signal name]"
"From U1-15 [signal name] "
It can help you clean up a cluttered schematic.
hugoleboot:
H1: male pin 15x2
That was not what I meant, what is it. I can see that it's a connector. What does it connect to electrically? Normally UCAP goes through a cap to ground.
The only signals on that connector are TXD,RXD,D+, & D-, so I'm guessing it's a COMM
cable.(to what I don't know)
Les seuls signaux sur ce connecteur sont TXD, RXD, D + et D-, donc je suppose que c'est un
câble COMM . (À ce que je ne sais pas)
That's right
it seems to me that I corrected all the errors with the datasheet and the documents of CrossRoads, I attach the shemat
Are there any errors (is it possible)? :o
image : Schematic-ATmega-core-project-2021-01-25-19-15-39 hosted at ImgBB — ImgBB
Please, click More, Modify, and use the Attachments and other options below the message box to Attach your drawing.
10k seems like a very high value for a led.
raschemmel:
10k seems like a very high value for a led.
Yes, 1K would be more than enough
I think you should reconsider how the schematic is drawn.
The power & ground lines make it hard to follow what is going on.
Redrawing the Power & Gnd sections, and adding a couple of +5 and Gnd symbols makes it a lot easier.
Converting your drawing makes it easy to see that the Reset buttons aren't connected to Gnd; and that +5 is missing in multiple places.
Using an arrangement like this cleans things up quite a bit, and makes adding the LEDs and current limit resistors much easier.
raschemmel:
10k seems like a very high value for a led.
In fact, I make a commercial product with a 3mm "power on" LED. Running from 12V and using 10k, it's almost too bright even though it also has to shine through a housing lens.
Actually, the "pilot" LEDs on many (most) Arduino boards and other modules are annoyingly bright.
They are presumably included on the proposition that these are only "experimental" modules and the "newbie" will want to know they are correctly connected to the power, but beyond that they are just a nuisance. 