Custom PCB for Arduino Nano. RXD pin causes no Upload

Hardware Nano Family Classic Nano
1

I have designed a custom PCB to host an Arduino Nano. I soldered the Nano in with no Components in place. The upload to the Nano failed. It had worked before I placed it on the board. I did everything I could find on the web to fix this to no avail. I cut all the traces from the Nano to any other component on the board.

Then I started on a new board. Soldering one pin at a time checking to see if I could upload the program after each pin. When I soldered the RXD Pin to the board. It stopped uploading. When I unsoldered the pin uploading worked again.

Nothing is connected to the RXD pin on the board.

What did I do wrong?

2

so why bother soldering it :wink:

you might think there is nothing connected there but may be there is a short and it goes to ground or something else... without the PCB layout and a picture of your soldering job, it's hard to tell.

3 Likes
3

Good Point about the soldering not needed. I can only plead old habits.

Here is the KiCad layout of that area. Pin 2 is RXD

image001.png1898×1420 113 KB

image002.png1314×1150 13.8 KB

Schematic

And finally PCB as soldered

image003.jpg480×640 76.3 KB

I did check impedance to GND on the board without any thing mounted on the board. No shorts that I could find. No connection to +5V either.

As you can see other pins have been left unsoldered also. (Live and Learn?)

Thanks for your interest and your help.

4

I would solder female header pins to the PCB and male header-pins to the nano, that way the nano is replaceable.

5

is the Nano flush against the PCB ? could you have interferences between the USB connector / associated components and the PCB?

6

Hi,
Is this Nano as in the original Arduino Nano.
OR
A Nano 33 IOT?

What forum section should this post be in?

Can you please;
Post a complete circuit diagram?
Post a complete PCB pattern?
Post some images of your assembled PCB?

Thanks.. Tom.. :grinning: :+1: :coffee: :australia:

7

Did you run the DRC (Design Rules Check) you have traces in areas they should not be, the DRC checks for this. The 5V between pins 5 & 6.

8

Thanks for the input. I did this on the second one. (learn from mistakes)

9

I did run DRCs on the board using the fabrication rules from my PCB supplier. The board did pass the DRCs. But I think your input is a good suggestion. I will reroute the +5V on the revision of this board.

10

Brand new on the forums so it seems I posted this in the wrong place. I am using a Arduino NANO

Apologies.

11

I used pins with a spacer on them. so the Nano is lifted of the PCB surface.

12

I think i said something about it before, but i use female headers on a PCB and male headers on the Nano. I remove the Nano for the upload.
Regardless, i don't see how if there is no connection through a PCB track, there can be any influence on the UART unless there is some kind of short through the soldering agent.

13

I am puzzled also. Back to the meter to check ALL the traces and through holes for a short!
Thanks

14

Thanks.. Tom.... :grinning: :+1: :coffee: :australia:

15

Thread moved as requested (by someone else).

In the future please flag a post in the thread then ask a moderator to take action.

16

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