I do not have a demultiplexer available, so I need a substitute. I have a TTL signal and I need to output the signal to output 1, then output 2, then output 3, then output 4 in sequence, meaning that when one of the outputs is high, the other 3 must be low. How do I accomplish this without using a DEMUX?
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Use a 7400 Quad Nand gate, use your microcontroller to set one pin on each of the 4 Nand gates (you'll need to use 4 outputs of the MCU). Into the other input of the Nand, you provide the Inverted data you'd want from that output.
Or provide the 4 control bits (not the data, but the control) using 4-bit shift register or 2 packages of dual D_FF the 7474. You'll need MCU outputs to provide clock and data. You will also have glitches in your de-muxed outputs.
answered Nov 22, 2017 at 3:23