SERIAL COMMUNICATION SYSTEM AND IMAGE FORMING APPARATUS

摘要

PROBLEM TO BE SOLVED: To attain a handshake when transmitting data from a slave unit to a master unit without providing a leased line for the handshake. SOLUTION: The serial communication system includes the master unit and one or more slave units. Each of slave units includes an informing means which changes a signal level of a status signal line connected to slave units to inform that preparations for transmission of a status signal have been made. The master unit includes a detection means for detecting that the signal level of the status signal line has been changed with respect to all slave units. The master unit includes a clock signal generation means which sends a clock signal for transmission of a status signal to a clock signal line in response to the change in signal level of the status signal line with respect to all slave units. COPYRIGHT: (C)2008,JPO&INPIT