Hello ALL! It would be very nice to get some help for the next question. I'm using a f12x µC. There are two active Uart's. I put a command on the Uart0 every 500ms. This command is transparent for this Uart and is sent to the UART1. The code for this function is: char xdata parsStr0[256]; void SendStringUart1( U16 command ) { ********** sprintf(parsStr0,"$%u",command); ********** } in this case I have a wrong parsStr0 every 5-10sec. After I've added a space in the sprintf ****** sprintf(parsStr0," $%u",command); ****** function I've not this problem anymore. Can somebody, please, explain me this strange behaviouar. With big respect, A.