Quick Question About Arduino Nano Blowing Up

[bostonman]

I have a Nano that was working fine. It had code on it for a tiny 0.96" display and I removed that display to install an OLED that I think used all different pins. If I remember, the tiny display only needed two A lines, power, and ground. The OLED uses all D lines. I didn't remove the old code before powering the Nano because it needed the new code uploaded.

Anyway, suddenly the laptop is reporting something is wrong with the device connected to the USB (the Nano). I've tried reconnecting several times, different ports, but another Nano works fine indicating this one is blown up.

My question is: are these sensitive and possibly the OLED fed back something to the chip that blew it up?

I'm not looking to repair this, but just wanted an understanding on where I possibly went wrong.

Also, does anyone have a good place to buy Nano boards? I bought these off Aliexpress, but went through work trying to find the cheaper priced ones. Some came in quantities of three, but included USB cables, others showed individual costs but was limited to one, etc.. One that I purchased had an old driver chip that didn't work with modern software. So I'm looking for a good source to not get old versions and not overpay for stuff I don't need like USB cables.

[themadhippy]

Ive used a fair few LG8F328P ( https://hobbycomponents.com/development-boards/1164-lg8f328p-qft32-mini-evb-development-board )  whilst not strictly an arduino they work just the same with a few extra features added.One thing they do lack is direct usb programing,but a suitable usb to serial board is dirt cheap.

[WattsThat]

Not to sound critical here but it’s apparent from your description of the connections you have little to no electronics knowledge. You might have used “A” connections one of the displays but in reality it was digital, not analog levels being output. The only analog a Nano has are inputs.

My money is on a connection error that killed the unit. Or, at least it has something disabled. Did you remove all the external connections, reload Arduino software and reconnect to the clone Nano via USB? Try that first.

Any clone Nano bought from Aliexpress is likely going to have cheap Chinese knock-offs of the original parts used by Arduino. If you want predictable behavior, spend the money and buy real Arduino’s or at least better quality stuff from Sparkfun or Adafruit. Buy from Aliexpress, sure you’ll save money but it’s up to you to figure out what USB interface drivers may be needed and what processor might be on the board you bought. Nothing wrong with most of them, they work, in the end, when you figure out what you have received for your $2.00.

[bostonman]

Not to sound critical here but it’s apparent from your description of the connections you have little to no electronics knowledge.

I won't comment.

The "A" connections simply meant the Nano has Ax and Dx connections, and I used the Ax connections.

Yes, I disconnected everything and tried communicating again, but it still showed a USB not recognized error.

[WattsThat]

Q: My question is: are these sensitive and possibly the OLED fed back something to the chip that blew it up?
A: No. Explanation: User error most likely (aka incorrect wiring)

[EggertEnjoyer123]

I've had this issue before.

Assuming nothing bad electrically happened to the Arduino, you should get another one and then reflash the bootloader. There are instructions on how to reflash the bootloader using another Arduino as the ISP online.

[Ian.M]

An Arduino Nano uses a dedicated USB UART bridge chip (FT232RL on genuine Arduino ones, usually CH340G or similar on clones).  The bridge chip handles all the USB interface stuff automatically, so if you are getting USB errors, that cant be due to corrupt firmware in the ATmega328P, so reflashing the bootloader wont help.  If however it enumerates correctly as a COM port, that can be opened without error, but AVRDUDE fails to program it, reinstalling the Arduino bootloader using an ISP capable programmer may well help.

Its generally a bad idea to rewire an Arduino without updating the firmware *AFTER* removing the old connections and *BEFORE* making the new ones, so the pins are setup as inputs and outputs compatible with the new wiring.  If you don't, there is a chance an Arduino output will conflict with an output on some peripheral device you have just connected, with a risk of damage to the Arduino MCU and/or the peripheral.   If you cant load an appropriate sketch with correct pin usage for your new wiring, because you are only just starting to develop it, then loading a blank sketch will let all pins default to being inputs removing the risk of conflict.

[bostonman]

Its generally a bad idea to rewire an Arduino without updating the firmware *AFTER* removing the old connections and *BEFORE* making the new ones

Something I hadn't considered before seeing this issue and the failure triggered that thought; going forward I'll practice this.

As you alluded to, it seems more an issue with the CH340, but you answered the questioned I sensed was an error on my part: I shouldn't wire it with an old program regardless; unless of course you're just tweaking the code.

If the CH340 chip is bad, I'd have to assume static electricity was the culprit as my work area is about 70% humidity (I'm running a dehumidifier too that doesn't take longer than a three-minute break).

If it's the 328, then it was either incorrect wiring on my part (I didn't check the wiring after discovering the Nano was blown, I just disconnected it and used another Nano), or the OLED fed something back.

Between the time it worked and didn't, all I did was add the OLED wires (kept the 0.96" connected) and then attempted to change the program from using the 0.96" display connected to the Ax lines (is Ax adequate since apparently it makes me sound as if I don't have any electronics knowledge?) to using the Dx lines for the OLED.

Obviously anything is possible, I could have rested it on a piece of wire, static electricity, connected it wrong, who knows, but the lesson is not to swap programs after rewiring it.