I have build arduino nano clone (only for desired pins i have made PCB when i connected to the pc it says USB is not recognized am i doing it properly? I shared my schematic and PCB
![Screenshot 2024-08-29 111557|638x500]
![Screenshot 2024-08-29 111557|638x500]
Please provide the schematic diagram.
Please describe how you connect it to the PC; looking at that PCB, I do not see USB so I assume that you use a serial-to-usb adapter (something like https://www.sparkfun.com/products/9716). And that should be detected by your PC.
maybe ch340 drivers are not installed
pls
check
also sometimes it needs specific capacitors/resistors
on the data lines
like on pro micro it needs 22 ohm resistors
check the datasheet
Hi @alajiprasaths. Please try this troubleshooting procedure and then report your results in a reply on this forum thread:
This procedure is not intended to solve the problem. The purpose is to gather more information.
- Disconnect the USB cable of the Arduino board from your computer.
- Open the Windows Device Manager.
- Select View > Devices by type from the Device Manager menus.
- Open the "View" menu.
- If there is a ✓ to the left of the "Show hidden devices" menu item, click on "Show hidden devices" to disable it.
- Take note of the contents of the "Other devices" and "Ports (COM & LPT)" sections of the Device Manager tree.
- Connect the Arduino board to your computer with a USB cable.
- Select Action > Scan for hardware changes" from the Device Manager menus.
Did you see any new device appear in the Device Manager tree after doing this? If so, please tell us where it is located in the tree and what it is named.
You can repeat steps 5-8 multiple times if you are not sure.
Check the polarity of the diode to USB chip pin 1.
I have installed the drivers. Normal Arduino clone is working fine but mine is not detected
but as malfunctioned one. Should I add 12 Mhz osc with it.
i did the each steps and when i connected original arduino Nano my lap recognized it.
but when i connected DIY clone it is not detected.
So that sounds like you have a hardware problem with your PCB. I'm not much of a hardware person but maybe somebody else can point out if you have a mistake in the schematic.
If it was my project, I would check all soldering around the CH340. If you have a scope, check signals.
I concur that the Device Manager result indicates it is a hardware problem. I wanted to check whether it might instead be caused by a driver problem, but I think that would cause a different result in Device Manager.
Yes I think I killed Ch340 
. Any way I don't have extra Ch340. Is there any way to upload code to Atmega directly using another Arduino UNO and I need schematic too.
You can use the UNO as a USB to serial bridge to upload through the ATmega328P's UART pins via the serial bootloader.
I'll describe the circuit connections. Hopefully that will be sufficient. If one of the other helpers wants to produce the requested schematic you are welcome to do so.
| UNO (Arduino pin number) |
Target |
|---|---|
| 0 | PD0 |
| 1 | PD1 |
In addition, you should connect the "RESET" pin on the UNO to GND to disable its ATmega328P so it can't interfere with the communication between the bridge chip on the UNO and the target.
The fact that I am instructing you to connect the pin on the UNO that is marked "RX" to the RXD pin on the ATmega328P and the pin marked "TX" on the UNO to TXD might seem wrong since we must always make RX-TX,TX-RX connections. However, this is actually what is needed to make such connections. The reason is that the markings on the UNO board are referring to the pins on the ATmega328P, but in this use case you are communicating between the UNO's USB to serial bridge chip and the target, and so must make the RX-TX,TX-RX connections between those two chips. The bridge chip has an RX-TX,TX-RX connection to the ATmega328P, so the pin marked "RX" on the board is actually connected to the "TX" pin on the bridge chip, and the pin marked "TX" on the board connected to the "RX" pin on the bridge chip.
Another option would be to use the UNO as an "Arduino as ISP" programmer. This would allow you to upload to the target by selecting Sketch > Upload Using Programmer from the Arduino IDE menus (instead of the normal "Upload").
There is some information about the "Arduino as ISP" programmer here:
https://docs.arduino.cc/built-in-examples/arduino-isp/ArduinoISP/
If you are interested in this approach and want further guidance (the tutorial I linked above is applicable, but is also focused on performing a "Burn Bootloader" operation instead of "Upload Using Programmer"), just let us know.