A multiplexer selects one of two (or more) inputs based on a control input. It then outputs the selected input.
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0answers
52 views
Why I am getting Unexpected EOF? What's wrong?
I am learning VHDL and I am trying to do a simple Generic MUX. It is my code:
GenericMUX.vhd
...
0
votes
2answers
87 views
How to multiplex a two-way data line?
I have a use-case where I need to control 4+ sonar sensors with a pic 628A microcontroller. The pic is also responsible for controlling a GPS and LCD so pins are scarce. The sonar sensors each have a ...
1
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1answer
37 views
Multiplex 125kHz RFID antenna
I'm looking to follow up on a question (asked by another) that wasn't answered to my satisfaction in another question.
RFID Antenna Array
I am successfully using the ID Innovations ID-2 chip to read ...
0
votes
1answer
39 views
8:1 Multiplexer With 5 Parameters of F(A,B,C,D,E) = ABCD +B'CDE+BC'D'
I am trying to create a multiplexer 8:1 with 5 parameters of the function $$F(A,B,C,D,E) = ABCD +B'CDE+BC'D'$$
what I did its to right it as minterms so what I get is:
$$ F = ABCDE + ABCDE' + AB'CDE + ...
0
votes
2answers
88 views
LEDs in the audio path - linearity? [closed]
I'm repairing an ancient stereo multiplex decoder which has diodes in the signal path for mono/stereo switching.
For headroom reasons, I need plenty of Vf on these diodes, which are pulled up by a DC ...
0
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5answers
116 views
Programmable IO
I have three bit input and would like to have a three bit output programmed for the input combinations.
...
2
votes
3answers
111 views
Three Phase Input to Single Phase Output
We have three phase input and the voltages in the three input is not the same always. Sometimes, one or two or three phase will be off. I would like to connect the phase to output which lies within ...
3
votes
1answer
71 views
Generating 19kHz and 38kHz phase-locked sine waves
As a personal project, I'm designing a stereo FM transmitter from scratch. Part of this entails design of a stereo multiplexer.
Using this description, I've worked out how I'm going to implement most ...
1
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2answers
90 views
How does this circuit multiplex an antenna between a transmitter and receiver?
I've built a Softrock RXTX kit (full schematic: pdf gif, see lower-left corner). It has one connector for one antenna used for both receive and transmit, but I don't fully understand (likely due to my ...
3
votes
2answers
97 views
32 bit, 4 way multiplexer
I'm relatively new to electronics and recently decided to design and build a very simple CPU as a personal project. My instruction size is 32 bits and I want to have 32 bit registers so I am going to ...
1
vote
1answer
30 views
Sample and Hold
When we have a data source oscillating at a frequency of say 4KHz , this implies that the Nyquist sampling rate would be at least ...
1
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1answer
66 views
Multiplexing with or without transistors
I'm doing something in where I need to multiplex 6 7-segment displays. About doing it, I found things like this:
And things in where the same thing is done without the transistors, just by ...
1
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1answer
68 views
Concept of Time Division Multiplexing [duplicate]
I have been studying the concept of Time Division Multiplexing, but I have not been able to understand some stuffs, for instance, I have not been able to understand why the sampling rate for audio is ...
2
votes
2answers
142 views
Multiplexing large LED matrix
I have a project which involves building a 64 x 48 (3072) LED matrix driven by a Raspberry PI computer. I am a first-year computer engineering student so I am still inexperienced with shift registers ...
-4
votes
1answer
125 views
Time Division Multiplexing question [closed]
I am new to the concept of Time Division Multiplexing in school, after reading a few books I came over this question.
With the help of sketches explain Time Division Multiplexing (TDM) in terms of ...
1
vote
2answers
80 views
Arduino multiplexing help needed.
Is it possible to use an 8 output demux to switch between seven 16 output demux's in the case that I want to control several LED's with an arduino uno? Is there a better way to do this?
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1answer
34 views
1
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1answer
83 views
Finding the no. of decoders required in cascading
I am trying to solve the following question.
How many 3 to 8 decoders with an enable input are needed to construct
a 6 to 64 line decoder without using any other logic gate.
I have a Digital ...
13
votes
2answers
41 views
How do I extend the number of analog (input) pins available to me?
I already know how to extend the number of digital pins on an Arduino using a multiplexer.
I want to increase the number of analog input channels that I have. One solution is to add another Arduino ...
0
votes
2answers
74 views
iCMOS analog switches and multiplexers
Does anyone have any experience with Analog Devices iCMOS high voltage analog switches or multiplexers like the ADG1434 or ADG1411?
The specs for iCMOS sound very impressive. But they've been ...
0
votes
3answers
135 views
Connecting more than one serial device to PIC16f877a
In my project i need to interface a gps receiver and a gsm modem to pic16f877a, But there is only one set of UART lines in this Microcontroller. Is it possible to multiplex these two devices using ...
0
votes
1answer
64 views
Getting Strange Readings From a Multiplexer
I'm trying to build a simple gamepad controller to learn more about multiplexers (in this case a SN74LS251. This is how I'm wiring it:
And this is the code I'm using to get the button states:
...
1
vote
1answer
189 views
Learning Multiplexing with LEDs, transistor switching speeds
I am working with some friends trying to multiplex. The issue we run into is we aren't sure if we are hitting a limit on transistor switching speeds.
I am unsure if this is a hardware or software ...
0
votes
1answer
107 views
4 bit mux input/outputs
If i have a 4 input mux with the output being in the form of
S1 AND NOT(s0)
MY truth table therefore looks like the following (remember NOT(S0)).
...
3
votes
2answers
93 views
Is upping the voltage on a multiplexed LED display an appropriate response for dimness?
I have a 10 character x 16 segment display that I'm driving using multiplexing off a PIC. The problem is, however, that with each display only being on 1/10th of the time, the display appears much ...
0
votes
1answer
70 views
multiplexing 16 sensors
I need to read 16 color sensors(TCS3210) one after another. So I am thinking of connecting all the outputs to a single atmega32 i/o pin and selecting a sensor using a demux showing low on the output ...
1
vote
1answer
100 views
Maximum LEDs on a matrix
There are several methods to drive LEDs using a microcontroller. The easiest method is just connecting all LEDs to an own pin on the microcontroller. Say you have \$n\$ pins available, you'll be able ...
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votes
1answer
407 views
Design a 4:1 MUX by three 2:1 MUX or by 2:4 decoder? [closed]
A 4:1 MUX can be built by using three 2:1 MUX. But I've not done it this way: I've used a 2:4 decoder to make a 4:1 MUX. Does it matter?
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2answers
348 views
Multiplexing an 8x8 Matrix - Why Transistors?
I'm trying to understand how to properly multiplex an 8x8 matrix (or any large amount of LEDs)
http://arduino.cc/en/Tutorial/RowColumnScanning
However, I'm getting a bit confused, since I've found ...
0
votes
1answer
143 views
Using Open drain to get +5V
I have a legacy board in my product that has 1 temperature input with 2 rtd temperature probes.
Until the new boards are ready the manufacturer has used a relay already mounted on the board to switch ...
8
votes
2answers
442 views
LED Multiplex Anode-Row Driver
I'm helping build this art installation that amounts to a large 16 x 16 pixel display. I settled on using 16 TI TLC5926 constant current driver chips chained together to give me direct drive to each ...
0
votes
2answers
201 views
Designing a good RF Transmission/Reception system for Embedded System
I want to have 4 sensors transmitting information to a microcontroller ie
4-bit Encoder -> Transmitter >>>>>>>>>>>> Receiver - > Decoder -> MCU
The problem I have is that if I use 4 transmitters and ...
2
votes
2answers
354 views
MUX verilog code
Can anyone explain the difference between the two codes below. Both written in Verilog, Xilinx. If someone can explain how the second one works would much appreciate it.
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2
votes
3answers
170 views
Best way to build a 64-bit output multiplexer
I'm looking to create something to multiplex N 64 bit signals together. The goal of the project is to provide digital switching between a library of old cartridge based video games.
Essentially I ...
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1answer
192 views
Implementing a shifter with only multiplexers
This is my homework question, I would appreciate any hints to help me get started.
A shifter is used to shift a string of 0's and 1's to the left or
right by a fixed number of positions. The ...
6
votes
3answers
1k views
Miniature Traffic Light with Raspberry Pi: Wiring many LEDs
Background:
I am a Civil Engineer specialized in traffic control devices and I have a small hobby project to build a scale model traffic light system. I can manage and control the traffic light ...
1
vote
1answer
173 views
Assigning ports of an n bit multiplexer
I have ONE n-to-1 multiplexer and I'm trying to assign its n input ports from another component which has n output ports. How can I do this?
My code is given below, and the errors.
I've ommitted ...
1
vote
4answers
132 views
How do I multiplex many signals into my sound card?
I'm looking for a recipe that will allow me to...
Hook 24 piezos to a box that will "multiplex" their output into a single signal that I can connect to the microphone input on a PC soundcard.
The ...
1
vote
2answers
96 views
LCD Multiplexing: Segment Off Voltages
I am reverse engineering a LCD (this is a raw bit of glass, i.e. no controller) and trying to understand the signals... there are 16 lines of which 4 are backplanes and 12 are segment lines.
The ...
2
votes
2answers
710 views
What is the minimum number of NOR gates needed to implement a 2-input multiplexer?
In the first chapter of The Elements of Computing Systems, the reader is asked to implement basic logic gates like Not, And, Or, Xor, as well as a 2-input multiplexer and de-multiplexer. The authors ...
0
votes
1answer
89 views
Building an 8 to 4 Encoder from a 8 to 4 Multiplexer?
I have a a 8-to-4 Multiplexer ICs (MM74hC4052N) and I want to use it as a 8-to-4 encoder or 8-to-3 encoder.
Is that possible? If it is, can drop me some hints on how to do that?
At one glance, I ...
2
votes
2answers
129 views
Is it bad design to use logic gates for multiplexing?
I have a PIC18F4550 which uses the same pin for UART RX and SPI data out.
Would it be bad design if I used a GP I/O pin and a logic gate to control the multiplexing of that pin?
When the IO1 pin ...
4
votes
2answers
604 views
7-segment LED display with multiple digits
I was looking at the datasheet for the LTC-4627JR, and it looks like each digit shares a common anode, and each segment shares a common cathode.
My question is given this configuration, I don't ...
6
votes
3answers
727 views
Best way to control 130 - 140 LEDS with Arduino Uno 32/64 bit led drivers?
I am new to electronic prototyping and had a few questions.
I need to control 132 LEDs individually. I want to make 3 rows ( 2 rows of 60 and 1 row of 12) I think i can matrix them but i would still ...
-1
votes
2answers
228 views
How to implement a 2-to-4 mux
Our logical circuit teacher asked us to draw the diagram of inside a 2-to-4 multiplexer and said it's going to be in our final exam. How is this circuit possible? I thought a mux always goes from a ...
0
votes
2answers
245 views
Multiplexer + flipflop all in one?
As you know if you have a 4 bits multiplexer, if you input 0101 the output 5 goes high, but right when you input another thing like 0001, output 5 goes low and output 1 goes high.
I need the ...
0
votes
0answers
421 views
How to Fix Multiplication Circuit using Logisim
I am designing a circuit that multiplies 2 bit 2's complement numbers.
The circuit uses Full Adder to add and Multiplexer to multiply and ALU for arithmetic.
I need feedback on whether the ...
4
votes
1answer
99 views
Can you pass resistance through analog mux?
I have a digital potentiometer that I want to calibrate by sending in my commands and then measuring what the actual resistance is. However, the resistance from the digital pot is (obviously) ...
3
votes
2answers
171 views
Differences between a FET multiplexer and regular digital multiplexer?
I need a MUX 8-1 with a very fast propagation delay; <10ns. I was searching Digikey and found a category of digital muxes called FET multiplexers, and their propagation delay is insanely fast < ...
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2answers
134 views
Mux for ultra low noise pre-amplifier
I am searching for a method for multiplexing 3 DC voltage sources (each ±10V p-p) to my ADC pre-amplifier circuit.
My requirement is that the multiplexer should not inject excessive noise into ...
