How to do a loopback test on a Nano

[S_Bartfast]

I am trying to upload a sketch to a new Arduino Nano but aren't having any luck.

I already have one Nano which works fine and a Uno that also works, however I have an additional Nano that I can't seem to get to take a sketch.

I've tried many things to get this failing Nano to upload and one of the pages I was following suggests doing a "loop-back" test.

I'm trying to follow these instructions but aren't getting any responce: https://support.arduino.cc/hc/en-us/articles/360020366520-How-to-do-a-loopback-test

Unfortunately when I attempt to do this I don't get any response from either of my Nanos). I do however get the expected response from the Uno, so I'm thinking I'm doing something wrong on the Nanos given that even the Nano that works fine doesn't seem to give anything back.

One thing I'm uncertain about is that there are two "RST" pins, both of which are next to "GND" pins. However I've tried shorting both sets of pins to no avail.

Can anyone explain how to do this loop-back test on a Nano, preferably with pictures/diagrams?

Thanks.

[UKHeliBob]

there are two "RST" pins, both of which are next to "GND" pins

That is not like any Nano that I have here. Can you please provide a link to where you got it ?

[pert]

This is a standard Nano pinout:

@S_Bartfast please tell us which Nano you have. Is it the:

• Classic Nano
• Nano Every
• Nano 33 IoT
• Nano 33 BLE

If it's the classic, we'll also need to know which USB chip your Nano has. This is the largest chip on the bottom of the board. Official Nanos and clones use the FTDI FT232R chip. Chinese derivative boards use the WCH CH340.

It's not possible to do a loopback test with the derivative boards.

[lesept]

Hi
In the French section of the forum, there is a tutorial on how to troubleshoot this problem ("my code won't upload"). If you can read French, just do it, otherwise use a online translation website such as Deepl, and see if you find the solution.