| 摘要 |
PURPOSE:To set automatically the device number of each unit just with the series connection of these units by providing a device number recognizing circuit and an address decoding circuit connected to said recognizing circuit on each unit. CONSTITUTION:If a device number setting signal 7, for example, is equal to '0000' with a device number recognizing/address decoding circuit 6, a decoder 8 delivers '0111'. Here NOR circuits 11, 12, 13 and 14 deliver '1', '0', '0' and '0' respectively, and the signal 7 equal to '0000' is sent to the unit at the next stage. When an address signal is equal to '0000', a decoder 9 delivers '0000'. In this case, a NAND circuit 30 delivers '1' as long as the decoder 8 delivers '0111'. The output of '1' serves as a chip selection CS signal and the corresponding unit is selected as long as the CS signal is equal to '1'.
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