Hello, I'm using a function to send char through the serial port. Sometimes, strange words (i.e ascii code 0x8 <VT>) are sent. I would like to know if some registers could be altered while an interrupt is occured. I'm using some interrupts, timer 0 overflow at each 1 ms. I saved the chars to send through the serial port in a temporary buffer. I verified if the strange word is stored within it and it does. Let me know what to do to make sure that nothing could be altered when an event is present. Regards Christian