Arduino nano schematic

Hi
Could someone check my arduino nano schematic, I ordered the PCB board and tried to burn the bootloader but I didn't succeed so I thought that the problem could be from the schematic.
Best regards,,

arduino nano.png

arduino nano.png

Have you built your own version of the Nano ?
Where did you get "the PCB board" from ?

yes I did, I got the schematic from two or three online schematics, because of that I'm not sure about mine.
I ordered it from JLCPCB with SMT assembly service.

arduino nano.png

You ‘did not’ give a net name for the output of the voltage regulator!
Should be +5v.

sorry I'm not expert in such thing.
Could you draw it over my schematic, so I can understand you better.
thanks in advance.

NAME the trace from U4 pins 2, 4 to +5V, that will connect to +5V on U1 and elsewhere.

I don't see a header for ICSP, it would have D11, D12, D13, Reset, +5V, Gnd on it.
How are you trying to load the bootloader? What are you using for a Programmer?
CH340 is not a Programmer.

I soldered the ICSP pins directly from the chip. about the programmer I don’t know I have just followed the followed schematic https://easyeda.com/editor#id=035b38c4d4e343b1942d83b200aedbca
But what do you mean about the U4 and U1!!?

The output of U4 is not named - if you use a multimeter, do you have a connecition from U1 to U4? I would think not. You may need to add a wire there (or from U4 to one of the other traces named +5V).

Where is the equivalent of J3 on the EDA schematic on your board? That is where the Programmer connects.
What do you have for a Programmer?

oh yea I got it. I soldered an additional wire over the board as you mentioned and tried to burn the bootloader again but still the same issue.
But I noticed that the voltage regulated to 4.7~V not like before I add the wire. thank you.

As for the ICSP pins I'm connecting them as the attached picture and I'm sure that they are connected perfectly and without a short with other pins.adding pic

How are we supposed to help when you do not provide the actual schematic? Your pcb clearly has a max232, none shown on any schematic provided and while it is not related to the boot loading failure, the CH340G requires a 12 MHz crystal, not 16 MHz.

Additionally, please post the text of the actual boot loading failure with the verbose flag set. This can provide clues as to the source of the problem.

Another observation. I'm not sure where the 2.5 volts is supposed to go but the output of U4 is going no where. D1 will stop any current from going to C7, C6 or USB1.

While I applaud our effort, I think you put the "cart before the horse" here. There are many subtle requirements to make this type of board function satisfactorily. I suggest you get a better understanding of the circuits operational needs before designing a PCB. In a number of areas, physical layout is very important. Said another way, a circuit board matching its schematic does not mean it will actually work and or work reliably.

You might also consider an alternate approach. Design a board that will accept and "production" nano then add your ancillary components to your board.

"D1 will stop any current from going to C7, C6 or USB1."
Exactly - keeps the 5V from the regulator from backfeeding into a PC when both are connected. I know my Lenovo laptop doesn't like that, it complains of a current surge and shuts down the port.

Check the wiring - gotta be something funny in the Programmer connections.

By the looks of the components on your PCB ‘you have not shown us the correct schematic’ for this PCB.

Is it top secret?

Not showing us the correct schematic makes it impossible for us to give you proper suggestions or answers.

Thank you guys for all of your suggestions.
I’m sorry I just didn’t add the rs232 schematic just because I think that the problem is from the my arduino schematic here are the full schematic and the board design after .

So now what I am supposed to edit regarding to the diode?
I ordered this PCB to test it and correct the designing mistakes to order another perfect one and I appreciate your help.

PCB.png

As for the (12 MHz crystal) is it for both crystals in my schematic?
and could you pick the correct SMD one to be used from Electronic Components Distributor | JLCPCB & EasyEDA Parts Online store - LCSC.COM
and how to connect it?

This seems like a rather advanced project. What is your electronics experience ?
Someone with experience would know that each trace or signal (NET NODE) should have a name (ie GND, +5v etc.)
Is this your first project ?
Did you breadboard the circuit and test it before ordering a PCB ? (to verify the circuit)

When I decided to build my own prototyping board with several pushbuttons and LEDs, a 4 by 4 keypad, a pot, a few spare pins and several 5V, GND and 3.3V pins I just put a socket on the PCB for a Nano. So much simpler.

When I decided to build my own prototyping board with several pushbuttons and LEDs, a 4 by 4 keypad, a pot, a few spare pins and several 5V, GND and 3.3V pins I just put a socket on the PCB for a Nano. So much simpler.

When I needed a quick and dirty programmer for my ATMega328s and ATTiny85s I used a ZIFF socket.
(I know, it's ugly, but it works perfectly all the time which is all I needed.)

A Nano uses an FT232L USB chip and requires a USB driver.
Does the CH340G require a driver and did you install it ?

A Nano uses an FT232L USB chip and requires a USB driver.

I have several "not real Nanos" here that use the CH340 with no problem. I presume that I installed the required driver but that is now lost in the mists of time