Unable to upload to Arduino Pro Mini

I am (still :) ) trying to build a smartwatch using and Arduino Pro Mini 3.3v 8MHz, Atmega328. I breadboarded the entire thing, got the display, bluetooth, acc/gyro/mag working, etc. (thanks to these forums). I then proceeded to solder the entire thing together. After doing so, I hooked it up to my laptop (Macbook Pro running El Capitan) through a CP2104 UART Friend (https://www.adafruit.com/product/3309). I tried uploading the code (some minor edits), but got errors saying "Programmer not in sync". I got all sorts of avrdude resp codes, such as 0xf3, 0x43, 0x8a. I believe that is what they were, there were a lot of different ones :confused: . I tried undoing the edits, no change. I then tried the Blink example, no different.

The wiring is all exactly the same as when I had it breadboarded. The serial monitor still receives info from the Arduino about the gyro sensor, the bluetooth still shows on my phone. Before I put it all together, the UART Friend would flash rapidly, but now it blinks a few times before the IDE gives an error. The Pro Mini green LED also blinks a few times. I am suspecting that it is a problem with the boot loader, but not sure how to test it. Pins 11, 12, and 13 are hard to access at the moment, which I believe is the pins to use for burning the boatloader. I would like to know before tearing into it to find out ;)

I read that using the "Upload with Programmer" will disable the boot loader, and I think I may have done that at one point, but if I remember right it still worked after that.

If anyone has had these same troubles or has heard of them and knows how to fix it that would be great, thanks!

Is anything connected to reset, pin 0, or pin 1 of the Arduino? Those pins must be clean during the upload process

If you briefly ground reset (the pro mini's don't have a reset button do they? If they do just use that), does the LED blink? If not, the bootloader is gone, reburn bootloader using an ISP programmer.

Does the LED blink just as if you'd grounded reset during the upload process? If not, suspect a problem with the DTR reset circuit.

Do you have the right processor selected? Wrong board/processor will generate similar errors.

Pin 0/1 are clear. Arduino Pro Minis do have a reset button, but using that doesn't help. I have tried different programmers, nothing. The green LED does blink when I press the reset button, so does that mean the boot loader is still good? Pins 11/12/13 are used for and disconnecting is out of the question :\

I have tried uploading the boot loader from and Arduino Micro, but nothing there. I get an error when trying to burn it: avrdude: Device signature = 0xffffff (probably .reduced_core_tiny) (retrying)

I have never used an Arduino Pro Mini before this project, and have only used USB cables before this so I don't have a lot of experience troubleshooting this kind of stuff :confused:

Upload with Programmer only works if you have a Programmer connected to the ICSP pins (11,12,13, Reset, Power, Gnd).

What Programmers have you tried to re-bootload the part?

I tried every programmer, the only one that says something other than "Could not find the usb port" is AVR ISP, the first item on the list. It says "Device Signature is 0xffffff, check wiring or use -F to override check". I have checked the wiring, using the Arduino MiniBootloader example (https://www.arduino.cc/en/Hacking/MiniBootloader)

Now I don't know what to try :/

I have also tried using an Uno for uploading/bootloader, but that is giving the same result :frowning:

OK so I have progress, but not sure in which direction :)

I was able to use my Arduino Uno to successfully burn the boot loader and run the blink sketch. However, the UART friend is still not working. But now I am getting a "resp=0x00" from avrdude, which seems like progress. I made sure the correct serial port is selected, etc.

FINALLY got it working. I forgot that if you "Upload using Programmer" then it erases the boot loader, and I had done that after burning the boot loader to make sure it worked before disconnecting the Uno and connecting UART. I tried re-burning the boot loader, then immediately connecting it to the UART and it seems to be working now! Sorry for the trouble :)