| 摘要 |
PURPOSE:To reduce the number of elements used in an up-down counter including decoder and, at the same time, to make the up-down switching operations of the counter easier, by constituting the (2XN)-notation up-down counter by combining a binary counter composed of one stage of T-flip flop and an N- notation Jonson counter. CONSTITUTION:A decimal (2X5) up-down counter is constituted of a binary counter composed of a T-flip flop 11 and a quinary counter composed of three D-flip flops 12-14. Clock signals CLOCK to be counted are inputted to the T-terminal of the T-flip flop 11 and each one terminal of three-input AND gates 15 and 16. The output of the binary counter is inputted to the N-notation counter where the output is counted and outputs of both counters are inputted to a decoder and, for example, numerical data of BCD are obtained. Switching between the up-counting and down-counting is performed by the Jonson counter. Therefore, many elements are not required for switching.
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