| 摘要 |
PROBLEM TO BE SOLVED: To prevent malfunction caused when a device responding to an extension address and a device not responding to the extension address are included. SOLUTION: A serial communication part 42 of a controller 22 reports the address of a communication object device of devices connected to a communication line 24 through the communication line 24 prior to transmission and receiving of data through the communication line 24. A clock generation part 44 outputs a clock signal to a clock signal line 26 while the serial communication part 42 is performing notification of address or serial communication. A buffer control part 46 determines whether the communication object is an extension address-responding device 38A or not, switches a three-state buffer 28 to a state for outputting the clock signal from the clock signal line 26 to a clock signal line 30 when the communication object is an extension address non-responding device 38B, and switches the three-state buffer 28 to a state for interrupting the clock signal from the clock signal line 26 when the communication object is the extension address-responding device 38A. COPYRIGHT: (C)2008,JPO&INPIT
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