Solve Multiplexing Conundrum with LS153 Circuit

  • Thread starter Mirek2010
  • Start date
In summary, the circuit does not generate outputs because it does not have a balun core. The device could be active but not generating outputs because it does not have the correct flip-flop.
  • #1
Mirek2010
6
0
TL;DR Summary
Stuck with simple LS153 multiplexer circuit
Hello,

I am hoping that you could help me understand why my simple circuit is not generating any outputs.
I used LS153 to design a circuit giving two outputs (4 to 1 conversion) on SIMETRIX.
The circuit when 'run' gets the required inputs (as I see them as a square waveform graphs) but the device is not generating outputs.
Would you be able to spare a moment to offer some clues as to what might be missing?
The inputs generated are as per the below table:

Outputs F1 and F2 will be true for AB and C states as listed:

A​
B​
C​
F1​
F2​
0​
0​
0​
1​
0​
0​
0​
1​
0​
1​
0​
1​
0​
0​
1​
0​
1​
1​
0​
0​
1​
0​
0​
0​
1​
1​
0​
1​
0​
0​
1​
1​
0​
0​
0​
1​
1​
1​
1​
1​

Thank you all for any clues,

circuit.png
 

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  • LS153_CIRCUIT_SIMETRIX.pdf
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  • #2
Address bit A is always the complement of address bit B. So only 2 of the 4 inputs are being sampled, namely states '01' = 1, and '10' = 2. Inputs '00' = 0 and '11' = 3 are never selected.

That explains why F1 output does not change.

But it does not explain why the changing state of Not(C) does not appear on F2.
 
  • #3
Thank you Baluncore, I narrowed the range of inputs just to get some response from the device on SIMETRIX.
I also created various 'single set of inputs' scenarios, and all did not produce any outputs.
What concerns me here is that the SIMETRIX does not even allow me to put a 'digital probe' on the output lines: I can probe any input lines but cannot probe output lines; it seems that the device is inactive but with all the various configurations of inputs, it remains inactive...there has to be a way to resurrect it...I hope
 
  • #4
Either look for an LED indicator to connect to the output,
or, maybe it needs something to think about.

Make an RS flip-flop from two cross-connected 74LS00 NAND gates.
The outputs of your Mux go to the RS inputs.
You can then probe the Mux outputs.
 
  • #5
If V1 and V2 are the same frequency there could be a problem. Try sketching a timing diagram. (yeah, using pencil and paper)
 
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Likes sophiecentaur

1. What is multiplexing and why is it important?

Multiplexing is the process of combining multiple signals or data streams into one signal for transmission over a shared medium. It is important because it allows for more efficient use of resources and enables multiple devices to share a single communication channel.

2. What is the LS153 circuit and how does it help solve the multiplexing conundrum?

The LS153 circuit is a type of integrated circuit that is designed to act as a multiplexer. It has two 4-input multiplexers in one package, allowing for the selection of up to 8 different input signals. This helps solve the multiplexing conundrum by providing a simple and efficient way to combine multiple signals into one.

3. How does the LS153 circuit work?

The LS153 circuit works by using control signals to select which input signal is transmitted to the output. The control signals are binary, meaning they can have a value of either 0 or 1, and are used to activate one of the multiplexers within the circuit. The selected input signal is then transmitted to the output, while the other input signals are ignored.

4. What are some common applications of the LS153 circuit?

The LS153 circuit is commonly used in electronic devices that require multiplexing, such as communication systems, data transmission systems, and digital displays. It is also used in computer memory systems and control systems for selecting between different input signals.

5. Are there any limitations or drawbacks to using the LS153 circuit?

One limitation of the LS153 circuit is that it can only select between 8 different input signals. If more than 8 signals need to be multiplexed, multiple LS153 circuits can be cascaded together. Additionally, the LS153 circuit may introduce some delay or distortion to the input signals, which can affect the overall performance of the system.

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