Hello guys, this is my first publication here and I come to ask for help in my project!!
I use the Atmega328P 32TQFP for some time in my projects, I use it in 3.3V with the internal 8Mhz oscillator, I never had any problems until today, when I'm doing a small production of my projects, I record the bootloader on the chip, I record my program (I use an arduino uno to make these recordings through the icsp) and the chip simply does not start the code when it is turned on.
I rewrote the bootloader and the program a few times and the processes occur without any type of error, but more than 10 cards that I am assembling presented this same problem with Atmega. I then did some tests and found that if I keep the RX pin at a high logic level, the chip starts, and after a few seconds of operation (about 30 seconds) it just starts going crazy and starts turning on and off several outputs, and on some boards the chip started to smoke and sparks. I just never saw this happening before, because I have done several other projects with the Atmega328P and it never happened, including that this project I am having a problem with, is a project that has been tested and evaluated previously, I have other boards of this project working perfectly .
I am attaching a print of the atmega part of my project and the circuit that goes to the RX pin, below I will leave a list of attempts to solve the problem I have already done and have not resulted in anything.
1 - I rewrote the code on the atmega without starting the Serial, however the chip only starts if I keep the RX pin at a high level.
2 - I recorded a simple blink code but it doesn't start either.
3 - I reviewed the Atmega welds on the plates and in none the existence of shorts (I use a microscope to check).
Has anyone experienced this situation or has any clue as to what is happening with my chips?