used the second is counted as the first mark bit of the idle the first character received after an idle period is an address character the idle line periods detected by the receiver are illustrated with one and two stop bits it is recommended to transmit an idle period of 11 bit instead of 10 bit the precise idle period generates an efficient address character identifier the first character of a blocks of frames can be identified as an address the time frame of frames within a block of information 39 s should not exceed the idle period detect time of 10 bits the idle line multiprocessor protocol is illustrated in fig4 each character contains an extra bit that represents an address indicator the first character in a block of data frames carries an address bit that is set this indicates that the character is an address the programming example of a serial uart communication protocol using the features of the 8 bit timer counter should follow these conditions the carry signal of the timer counter module is selected for the interrupt source instead of p0 1 source the according vector contains the address of the transmit receive interrupt routine the first instructions separate the program flow.