| 摘要 |
<p>PROBLEM TO BE SOLVED: To efficiently use a terminal to which two functions are assigned even during the execution of a program by switching more than one terminals so that they function as a bus or input port at need. SOLUTION: According to a bus/port setting signal B/PSET and a reset signal RST outputted from a CPU while hardware is initialized, a B/P register 3 sets a terminal 5-0 as a bus or port. With a data signal DATA and a bus/port write signal WRBP, the terminal 5-0 is switched to the port or bus during the execution of the program. Further, the terminal 5-0 is switched to the bus or port according to the program. Consequently, the terminal 5-0 having both the functions of the bus and port can be used as either the bus or the port, so respective terminals 5-0 can effectively be utilized.</p> |
