Posted on May 17, 2011 at 13:52OK, found. Big Nerd mistake... I had another interrupt (timered) that desactivated this USART2 instead of USART3. Too much communication lines on this controller !!!

Posted on May 17, 2011 at 13:52I agree that an overrun can cause that kind of an interrupt. But the first thing I do when entering this IT is read SR register (which is 0x80), and only TXE is activated. Secondly, according STM32 ref manual, figure 2...