So i have had my Arduino pro mini connected to a breadboard to test sketches and wiring schematics.
I then soldered all wires in place and attempted to reconnect to upload and create the actual program i need. After reconnecting, I can no longer upload any sketches. I spent 4 hours trouble shooting, and still no luck... So i'd like to know if i've bricked my arduino, or if there's something i've missed...
Info:
Arduino Pro Mini Clone - ATMEGA328P - 3.3v 8MHz
FT232RL FTDI Adapter
Arduino IDE v1.8.13
FTDI Driver v2.12.28
Errors:
avrdude: stk500_getsync(): not in sync: resp=0x**??**
Almost every time i attempt to upload a sketch, the last 2 digits (where the ?? are above) will change... i've received 00, 20, 30, 0a, 1c... and a few more... never consistent.
Completed Troubleshooting:
Successfully conducted loopback test with FTDI adapter on its own. No issues with it at all.
Changed FTDI driver to 2.12.16 and 2.08.24
Changed baud rate from 9600 to 57600
Updated all libraries and boards
Complete removal of IDE and reinstall
Tried different timing of manually pressing reset button
Confirmed Board, Processor and Port are all correct, dozens of times.
Desoldered EVERYTHING i had put onto the Pro Mini and cleaned with acetone dipped cotton bud
Checked and double checked wiring from FTDI to the Pro Mini
Tested multiple example and blank sketches
Attempted to burn bootloader (still receive time-out and not in sync errors)
Searched pretty much every thread i can find on the issue, only to see a million responses about checking the port and burning a bootloader...
Notes:
Like i said at the start... i had everything working perfectly fine.. i've no doubt in my settings, FTDI, or connection between FTDI and Arduino as it all worked, nothing changed. I simply soldered the wires i had after testing schematics, and now it doesn't work, even after desoldering everything.
Also, only some red LEDs light up on the arduino when plugged in. Nothing flashes when attempting to upload a sketch, and nothing changes when pressing the reset button.
Have i bricked the Arduino? Is it super sensitive to heat (i was soldering about 7 pins quickly without a break)?
Any new information would be greatly appreciated... i'm banging my head against a wall at this point!
Unless you were soldering those pins with a blow torch. that's not the issue.
The problem with errors like that is it tells you basically nothing about what might be going on, other than that it's very unlikely to be a driver problem.
Nano vs Nano (old bootloader)? (around 2 yerars ago the official store started shipping nanos with a new bootloader that ran at 115200 baud instead of 57600; had you just now updated the IDE from a pre-new-bootloader version, the nano option that used to work would no longer work, because now Nano assumes the new bootloader unless told otherwise..
Oh - is anything connected to Arduino pin's 0 or 1 (RX/TX)? Those are used to upload sketches. Reset too. Could you have left a solder bridge between 0 and 1. or between a one of those and Vcc, Gnd, or similar?
Does the light blink when you press reset (or briefly connect ground to reset, I forget whether nanos have a button)
Wrong port selected? Wrong board selected? Circuit board sawn in half and the part with the microcontroller thrown away? (all of those will give that error message). Helping people with this error is no fun, and since we're not being paid for this, we don't like doing it. It is guaranteed not to be interesting for the person helping, and the list of what could cause it is a mile long.
Thanks a lot for your time to reply... understand that this is a really crappy error, and appreciate your time regardless.
The thing that is shitting me the most, is it was working perfectly fine before i soldered everything. I was able to upload code with no dramas.
I guess i can list a few things now to try and cross off the list.
It's a Pro Mini, not the Nano. Not sure what bootloader is present, but apparently is some chinese version (since it is a clone), that automatically sets the clock i think (i'm brand new to this so struggle to understand that).
Pressing the reset button on the pro mini does nothing at all
Nothing was ever connected to pin 0/1. There are also no solder bridges, however there is a little bit of flux on the board that is bridging... didn't think that was conductive though.
Just received an Arduino Uno today to use as 'Arduino as ISP' to flash a new bootloader, or anything for that matter. Still the same errors.
I tried Nick Gammons sketch (https://www.gammon.com.au/forum/?id=11635). I was able to upload the correct sketch to my Uno, but there are no helpful instructions from that point. After playing around, I had no luck with being able to flash a new bootloader. I would love more info/in depth guide on this however, as apparently this method bypasses any AVRDude crap.
Tried a 22uF capacitor between GND-RST of the Uno while having it connected to the pro mini... made no difference.
Tried 2 computers, 3 devices for programming (Uno, FT232 FTDI, USB ASP/ISP), 1 Pro Mini (2nd one should arrive in 2 weeks). So the fault has to lie with the Pro Mini itself.
Just to reiterate... I had programmed the Mini with the FTDI before soldering everything. I only have 1 port, so it isn't wrong... no other settings of mine changed (board, processor, baud rate, com port, etc...) from when it was working and now not working.
When i get my new Pro Mini, ill try that... then the old one again with the same settings and just confirm its the actual Mini that is damaged.
I guess what i can do in the mean time is desolder all header pins, clean it really well and remove all solder paste etc, check all SMD components, and try programming without completing any soldering...
For anyone who's interested...
My issue turned out to be both the new Arduino Uno and the Solder Flux on the board.
I didn't know flux was that conductive... enough to short out pins on the Arduino. After desoldering every header pin on my Pro Mini and cleaning it thoroughly, I resoldered 6 headers without flux and plugged it all in....
The Uno started giving me signature errors for which I still have not figured out...
I then tried my UsbAsp and after some tinkering with the drivers on my Linux system, I was FINALLY able to successfully load a sketch to my Pro Mini.