| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To allow a communication system to detect idle state of a communication line in software manner at serial communication among a plurality of communication systems. <P>SOLUTION: An edge detector detects a rising edge of received data and holds the fact. When reception of 1 bite data is completed (time t1), a reception interruption process resets a rising edge detection state at the edge detector, and sets a timer to be a prescribed determination time T. Then, a timer interruption process at time t3 determines presence of rising edge during the determination time T, and determines to be busy as the rising edge is detected. The reception interruption process similar to that of time t1 is performed at reception completion of next 1 bite data (time t4) again, and timer interruption process is performed at time t5 after the determination time T has passed. Since no rising edge is detected at that time, it is determined to be in idle state. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
