Arduino not showing up on Ports list (Mac)

[ep01256]

I know this has been asked a lot but I have searched pretty much everywhere and have not resolved my issue. I think I have bricked my Arduino because all the tests I've done, it hasn't shown up on the ports list. From my research, I'm pretty sure it has to do with the Atmega16u2 not working, stopping the computer from recognizing the device. I've attempted the loop back test (but have to have the Arduino recognized by my computer to do this), reburning the bootloader, and even buying a new bootloader. I have also installed usb drivers on my mac as well.

I am using an Arduino UNO Rev3 which I bought last year and MacOS 11.2.2 Big Sur.

The last sketch I uploaded was a blank sketch. The L LED is solid lit even when I press reset and the TX and RX LEDs are dim but solid.

Please if anyone has any solutions that don't involve modifying the physical board that would be great.

Images:

[J-M-L]

have you tried on a PC?

have you read this? https://www.arduino.cc/en/Hacking/DFUProgramming8U2

• Mac OS X: run the System Profiler application (e.g. by selecting "About This Mac" from the Apple menu and clicking the "More Info..." button); go to the USB sheet and click on the item for the Arduino board. The firmware version is listed as "version" (e.g. 0.01 for rev. 0001).

I suspect you don't see anything there?

that's what I see

[ep01256]

The arduino doesn't even show up anywhere, and yes I have tried on a PC (it didn't show up).
This is what happens on my Mac:

[J-M-L]

If it does not work on PC either you might want to explore DFU for the chip…

I never had to do it so can’t share experience

[ep01256]

It just doesn't show up at all even through the tests I did. I'm going to try using a USB to FTDI board to try to communicate with it.

[ep01256]

Also, does the resistor in between the 16u2 and crystal do anything? On my board it doesn't have it but on others it does.

[J-M-L]

I don’t know enough about that part to help out there

[Dozie]

Download and install the latest FTDI driver

1. Download the driver executable file from FTDI's website here into the Arduino drivers folder on your computer and run it from there.
2. In the dialogue box that opens, extract the executable installation file.
3. On the FTDI CDM Drivers dialogue page, click on Extract.
4. Click on Next in the Device Driver Installation Wizard dialogue page.
5. Thick I accept this aggreement and click Next in the Licence Agreement dialogue page.

Click Finish to complete the installation.

[ep01256]

I have done this before but I can try it again. Also, if you read above, do you know what that resistor is for?

[Dozie]

The board you posted is not an official Arduino board, so the design might be different from the official one.

[ep01256]

I am aware of that, I just wanted to know if it made a difference.

[er_name_not_found]

According to the data sheet that's xtal1 and xtal2.
I believe that on yours the xtal2 is likely configures as PC0 instead of a clocked output so this board has an extra digital pin.
Absolutely 110% a guess and should be taken as such.