| 摘要 |
PURPOSE:To guarantee normal operation without giving external disturbance to other device even if a board is inserted with a hot line by mounting a multiplexer and a temporary storage device on a board, switching the multiplexer according to the memory content of the temporary storage device and transmitting a data. CONSTITUTION:In inserting the board to a hot line connector, power is applied but the memory content of the temporary storage device 2 is not guaranteed. Thus, an input data from input signal lines SHWo-SHWn to the multiplexer 1 is outputted in error in this state and this output is inputted to one switching gate 4 via a flip-flop 3 for retiming. A switching control register 5 in this case is reset by a reset circuit 7 so as to inhibit the other input to the switching gate 4, which is closed. Then the switching control register 5 is set by a program from a gate control circuit 6 interpreting the software order and then the switching gate 4 is opened so as to output a data at normal use. |
