| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a board connection device which can appropriately process a terminal that is not used, which is superior in resistance against noise and which can execute a stable operation only by connecting a circuit board. SOLUTION: For connecting the circuit boards 1, 2 and 3, the output buffers 302 and 303 of the circuit board 1 dealing with output signals which are possible to be not used from three state buffers. CPU 320 identifies the circuit board of an opposite party by IDR 307 and IDS 309 and controls the output buffer 302 or 303 of the signal which is not to be used in accordance with the result to an open (high impedance) state. The other end of the signal which is not to be used is grounded on the side of the circuit board 2 or 3. The input signal of the circuit board 1 is grounded on the side of the circuit board 2 or 3.</p> |
