Hello Diego,
thank for your interest, I'm sorry for my late, I didn't receive the notify through email.
The strange is that the code runs well also in overflow. I didn't touch the linker configuration or some other setting, just created a new project and start using a simple SPI.
The problem, now, is that the issue dissappeared. I worked this week regardless the stack overflow, this morning I would have shared the project with you, so I checked the problem again but now I don't have anythig to show with you, it works properly.
I don't want to waste your time, I will open the topic again as soon as the problems comes out.
Thank you so much.