I have good news: I managed to program the firmware on our QFN32 board. Problem solved!
Summary of the Solution
I believe the issue was related to the reflow temperature. Here’s a detailed explanation:
I manually soldered three boards using a hot air soldering station. The second board was adjusted for the MCU-Link Pro programming connector, and the third was due to the first two lacking the RC circuit on the RESET pin, which I suspected might have damaged the microcontroller. The third board was being detected until yesterday when I decided to take some signal measurements and removed the RESET pin to understand what was happening during programming, using a logic analyzer. After undoing these changes, the microcontroller stopped being detected.
This morning, I replaced the microcontroller on the third board and noticed the prolonged heating time for the microcontroller and PCB. They were exposed to high temperatures for over a minute to solder (using wire solder and paste flux).
To send the board to Alessandro in the same previous condition, I decided to do one last assembly: using solder paste and reflowing it in an oven, as would be done in the SMT process (except for Pick and Place).
After reflow soldering, I reworked the board, assembled the connector and necessary jumpers, and checked resistances and continuity (I took this care with the other boards as well). I tested it, and it worked:
- It is connecting and programming via J-Link Commander (the third board only connected but did not program).
- It also worked in the IDE.
I was worried there might be an issue with this package since it is a new microcontroller. I apologize for the concern, but I needed to reach out to you.
BR,
Rodrigo