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Questions tagged [tri-state]

A signalling standard typically used in buses that either drives the wire low, drives the wire high or disconnects from the wire (Hi-impedance, Hi-Z or tri-stated) such that there will not be a driver conflict when the wire is driven by another unit/driver. Two low impedance drivers driving to different levels (High Vs. Low) can potentially damage each other but certainly will corrupt the data on the wire. Allows for shared wires (with coordination).

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Might this tri-state level shifter work?

I just thought of this idea for a one-directional tri-state level shifter that does not need an output-enable pin: The idea is that if the input A driven hard (high or low) then it just behaves as a ...
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Tri-state input [closed]

I'm familiar with tri-state outputs. They can be high, low or high-impedance. Now I read somewhere that tri-state inputs can detect wether they are connected or not. Aren't digital inputs always high-...
Piglet's user avatar
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2 answers
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What is the difference between an N-MOS FET and a tri-state buffer? [closed]

Is an N-MOS FET an equivalent of a tri-state buffer, where the source is the input, the gate is the enable, and the drain is the output?
Sny's user avatar
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2 votes
1 answer
223 views

Tri-state input to three logic states

I'm looking for an IC or small circuit that implements the following truth table: Input Output 1 Output 2 H H L L L H Z H H Is this possible? The purpose is to keep an SPI SS signal pulled high ...
inc's user avatar
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1 vote
2 answers
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Why do we use a MUX rather than tristate buffers to implement a bus?

Consider a small digital system consisting of registers connected to a bus interconnection network. It is well-known that the output to the bus can (functionally) be implemented either with tristate ...
EE18's user avatar
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8 votes
5 answers
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What is the difference between a tristate buffer and a transmission gate?

Functionally, these two "blocks" seem to do the same thing: send input to output if enabled and present high impedance Z on the output if not. However, this answer seems to suggest a ...
EE18's user avatar
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1 vote
2 answers
127 views

Isolate unpowered MCU UART

I'm an EE student working on my first hobby project involving ECAD and currently I have an ESP32-C3 connected to a BM83 Bluetooth audio module via UART. There will be moments when only one MCU is ...
Krille002's user avatar
3 votes
3 answers
215 views

Is there any such thing as a tristable, quadristable, etc. multivibrator?

The title says it all. Is there a discrete circuit that can produce 4 different outputs based on a single tactile switch click? I'd like to do this with either a discrete design or a 74373 since ...
Aaron Butkovich's user avatar
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0 answers
21 views

Tri-State gates in CMOS [duplicate]

How do you build tri-state gates on transistor level? I've tried to come up with some designs -like connecting the output of the gate to the source port of a PMOS transistor with the enabled signal as ...
Amirreza Nadi Chaghadari's user avatar
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1 answer
50 views

Looking for a Quad 3−State Noninverting Buffers in DIP package [closed]

My application is a half-duplex serial communication (2 buffers) and a switch for a 35 to 60mA load (1 buffer). I found On Semi MC74HC126AN (https://rocelec.widen.net/view/pdf/h52tembhav/ONSMS12940-1....
Paul Jurczak's user avatar
5 votes
4 answers
2k views

How can I differentiate between high and high-Z state?

I'm using this MCP73831 device. I want to know how what to expect as a voltage level on the STAT pin when the below chart on page 13 says, STAT = HIGH & STAT = HIGH-Z. When the charging is ...
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0 votes
2 answers
77 views

Treating a high-Z input as both high and low at the same time

Setup (not strictly necessary to answering the problem; supplied for the curious): I have a single logic output pin from a device, logic 0 = 0 V, logic 1 = pulled high to Vcc through a 10 kΩ resistor. ...
Arby Bellie's user avatar
1 vote
2 answers
98 views

How is this capacitance affecting other parts of the circuit?

I'm attempting to drive a matrix of LEDs. Columns. Rows. It flickers too much for my liking, so I tried smoothing the LEDs with capacitors, but I'm getting very odd behaviour. Here is a minimal ...
Sod Almighty's user avatar
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3 votes
1 answer
366 views

Implementing three-state logic

Can we build a three-state logic gate using only transistors (or basic logic gates)? If so, how is it built? I'm trying to build a model for an 8-bit computer in LogiSim, and I'm trying to find out if ...
Rd Basha's user avatar
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1 answer
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Converting 2-line gate driver PWM to 1-line 3-state

I'm a software engineer, not really experienced in the hardware design, looking to confirm if I correctly designing the following piece: I have a FOC motor controller chip (TMC4671) that is only able ...
Max Matveev's user avatar
2 votes
0 answers
99 views

Capacitance/length limitations when daisy-chaining microcontrollers

I'm doing a daisy-chain of microcontrollers, with a half-duplex bidirectional line going from DOUT/DIN ports. I was thinking of doing tristate for the ports, and have a pull-up resistor connected to ...
Azmisov's user avatar
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4 votes
2 answers
3k views

Transmission gate vs Tristate Buffer

I am wondering about the practical difference between transmission gates and tristate buffers. As far as I can tell, they both do the same thing. They effectively disconnect themselves from part of ...
DrZ214's user avatar
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1 vote
1 answer
2k views

System Verilog Mux Implementation using tri-state buffers

I found a verilog implementation of a mux using tri-state buffers in the document UMD Lab Tutorial on Verilog (I'm not a student, graduated 2 years ago :)) ...
nebuchadnezzar_II's user avatar
0 votes
1 answer
126 views

Bi-directional Three State IO and microprocessor gpio

I want to use an MP5010B Electronic Fuse IC. I will enable or disable it by using the Enable/Fault pin which is billed as a bi-directional three state IO. I will enable or disable this pin using a ...
gmlux's user avatar
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3 answers
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A transistor and a diode instead of a tri-state buffer

I was wondering if it is possible to replace the tri-state buffer with a transistor and a diode as shown in the image. In this case a zero will be the same as high impedance. I don't understand why we ...
Ctvpd's user avatar
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2 answers
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PIC16F18446 Tristate output pins controlled by the value of another pin

In many 74xx chips the high impedance state of pins is controlled by a OE pin. I want a similar functionality for my PIC device. I understand that I could use code to flip the config bits to make the ...
johnlon's user avatar
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2 votes
1 answer
767 views

Bus contention when addressing tristate buffers by decoder output

I'm currently redesigning the signal propagation algorithm of a circuit simulator I'm developing as a hobby project (https://www.antarescircuit.io). In the new design, I'm trying to detect when ...
flandreas's user avatar
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0 answers
246 views

"Working" tri-state MOSFET Push-Pull leakage

I have been working for a while on this design, where there are 9 push-pulls that should drive a charliplexed LED array. Therefore the circuit must be able to provide three states, namely: HIGH(12V), ...
Smart_Celery's user avatar
1 vote
1 answer
285 views

Why does an oscillator want a capacitor between Output and Tri-State?

I'm looking at the datasheet for an oscillator: ECS-3225MVQ-500-CN-TR https://www.mouser.se/datasheet/2/122/ECS_3225MVQ-1825332.pdf As you can see, if Tri-State is not connected(NC) or pulled high (...
euraad's user avatar
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0 votes
1 answer
355 views

Tri-state push-pull configuration GPIO protection

I am designing a sort of "driver" for a high voltage Charlieplexed LED array, since normal GPIOS can't handle 12V. For that, I need to be able to use tri-state logic, which means LOW, HIGH, ...
Smart_Celery's user avatar
0 votes
1 answer
170 views

Will these optocoupler configuration work to tri-state high voltage GPIOS?

I am trying to control an array of LEDs that require a very high voltage due to the high impedance of the connections (there is no option to change that). Since the charlieplex configuration makes use ...
Smart_Celery's user avatar
0 votes
1 answer
155 views

How can I control a "high" voltage charlieplexed LED array?

Context I want to design a system that allows me to control different LED arrays that I have, which can be either conventional multiplexed arrays (MP) or charlieplexed arrays (CP), by just plugging ...
Smart_Celery's user avatar
1 vote
2 answers
74 views

can connecting a tristate buffer output to 0 or 1 make problem?

in this circuit the control line is connected to GND so the output is Z. is there any problem to connect the output line to 1 or 0? if the control line turns to 1, what happen to the circuit? what is ...
sadegh yeganeh zadeh's user avatar
-2 votes
1 answer
134 views

Is tristate buffer power consumption high?

I have 2 questions about tristate buffer. Is there any problem with using many tristate buffers in circuit design? is tristate buffer power consumption very high? Is it a good solution to replace a ...
sadegh yeganeh zadeh's user avatar
1 vote
1 answer
386 views

How to use tri-state buffers to make AND and OR logic gates? I can use an inverter

It's for an assignment where I have to make AND/OR gates using tri-state buffers and NOT gates. Is there any way I can do that without using any other gates?
Ahmed_isstilllearning's user avatar
1 vote
1 answer
155 views

Can a resistor mitigate a maximum input voltage limitation?

I have a microcontroller running at 5v and outputting a digital signal. This signal can be high, low or high-impedance (tristated). This signal goes to an input pin on a target chip (the type of which ...
Sod Almighty's user avatar
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0 votes
0 answers
179 views

using RC delay to trigger output enable pin of tri-state gate

The attached image is a circuit using a rc-delayed (reset) signal to control a tristate gate (U855C). After MPU_RESET is asserted, C852 starts charging. Gate U855D is always enabled. When the ...
matianfu's user avatar
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1 vote
0 answers
61 views

A bus routing puzzle, does it ring a bell?

I am breaking my head over a puzzling bus routing puzzle, and I wonder if this sort of problem rings a bell. I have 4 memory cell ports, let's call them EE, OE, EO, and OO, that are being mapped to 4 ...
Gunther Schadow's user avatar
1 vote
1 answer
261 views

Do UART pins on the Beagle Bone Black require tri-state buffers?

The project I am working on uses a Beagle Bone Black (BBB) rev C, we are powering it externally through a cape according to the System Reference Manual's instructions. The System Reference Manual ...
tzengia's user avatar
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0 votes
4 answers
3k views

How is high impedance state physically different from a logic low state?

I have read this question and the answers that follow on the electrical stack exchange but I still face a difficulty in understanding the practical difference between high-Z state and 0 state. It is ...
Shashank V M's user avatar
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1 vote
2 answers
834 views

Tri State Buffer and Boolean Algebra

The basic operators of the boolean algebra are AND, OR, NOT. The modern digital circuits are based on this mathematical concept (Shannon's thesis, 1938). I am wondering whether the Tri-State Buffer ...
u4783731's user avatar
0 votes
1 answer
1k views

Assigning a value to a tri data type variable in Verilog

Suppose there is a 'tri' data type variable A declared in a module m in verilog. A is connected to the output of another module n which is instantiated twice inside m, in both the instances. In one ...
Sai Krishna Garlapati's user avatar
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2 answers
492 views

What makes a input GPIO pin so sensitive?

I know that an input pin has a high impedance, but how a high impedance makes such pin be so sensitive? According to https://forum.arduino.cc/index.php?topic=454553.0 -- #4 mentioned If the input ...
mannok's user avatar
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9 votes
5 answers
1k views

Does ISA bus (or PC/XT bus) have some means of arbitration to resolve bus contention?

My understanding of ISA bus is that the CPU places an address on the bus and any expansion card is free to respond to that address by taking control of the data bus. I presume that tri-state buffers ...
Chris_F's user avatar
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0 votes
0 answers
131 views

Avoiding shorts when switching between bus lines with a mechanical switch

I've designed a circuit to choose between two 8-bit digital buses. I'm taking advantage of the fact that the 74AC540/541 chips have tristate outputs, so can enter into high impedance state to allow ...
Sean's user avatar
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1 vote
4 answers
3k views

Why am I getting an error when setting the TRIS registers with PIC?

I am new to PIC programming, and I am trying to blink an LED using the PIC10F206. It has 4 I/O pins. I understand I must declare them as inputs or outputs, but the IDE I am using (MPLAB) keeps giving ...
Sal M's user avatar
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2 votes
2 answers
230 views

Is this circuit from a textbook wrong?

(This is not a homework question.) While reading "Digital Computer Electronics" by Albert P. Malvino, I found this circuit on page 121, figure 8-22(a). It claims to be an example of a discrete TTL ...
Sod Almighty's user avatar
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1 vote
2 answers
531 views

Tri State/Floating Signal Detection

I'm working on a project for automotive environment in which I need to read signals from the power mirrors switch in a microcontroller. The power mirrors switch controls the mirror's moving directions ...
Roga's user avatar
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-1 votes
3 answers
1k views

How is the enable pin implemented in tri state logic?

I watched Ben Eater video on Youtube giving an introduction to tri state logic (https://m.youtube.com/watch?v=faAjse109Q8&t=98s). He first presents a circuit made of two transistors (see picture) ...
Winston's user avatar
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3 votes
4 answers
677 views

Is it possible to make a tri-state bidirectional buffer without any tri-state buffers?

I'm currently making a computer in an application called Smart Logic Simulator. It does not have any tri-state buffers and therefore I cannot make a bus (based off the DM74LS245 chip.) Is there a way ...
enthusiasticGeek's user avatar
0 votes
2 answers
248 views

Choosing the best approach for data selection in a datapath

For a university project, I have to design and construct a very simple CPU including the ALU. In order to select between different data lines that go into the ALU(32-bit data line), I have thought of ...
Abishek0398's user avatar
0 votes
1 answer
310 views

Logic levels on tri-state buffer,

i am working on some CPLD-controlled SPI devices that will be daisy-chained together. I will be using 74VHCT126AFTTR tri-state buffers to disconnect the SPI and Slave Select lines on the device from ...
Christoph Tönnis's user avatar
8 votes
5 answers
4k views

Reasons for having MCU pin-states default to pull-up/down out of reset

On many MCUs, pin-states default to tri-stated (a.k.a. analog inputs) when the MCU resets so as to not affect the circuits they are connected to until software configures the pins. The tri-stated ...
TRISAbits's user avatar
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1 vote
1 answer
408 views

Question about bi-directional pin from Roth reference

I now am studying the tri-state buffer from the reference "Fundamental of Logic Design", 6th edition, By: C. H. Roth and L. L. Kinney. I found that circuit of a bi-directional pin as application of ...
Osama El-Ghonimy's user avatar
0 votes
2 answers
170 views

Can a Tri-State buffer be used with AC signals?

I'm trying to switch an analog audio line from its given channel to analog ground when a specific line goes low (in this case, the DACs charge pump goes low when it shuts down). Would a tri-state ...
t3ddftw's user avatar
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