Questions tagged [shift-register]

A shift register is a cascade of flip flops, sharing the same clock, in which the output of each flip-flop is connected to the "data" input of the next flip-flop in the chain, resulting in a circuit that shifts by one position the "bit array" stored in it

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Questions on piso shift register and simulating in LTspice

After my previous question, I attempted to simulate an 8-bit "parallel in serial out" shift register in LTspice as follows: The above schematic is not very readable due to its size so below is the ...
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38 views

Help with understanding the mechanism of this parallel to serial shift register

Can the following shift register operation be explained step by step manner?: How does the MUX function? What happens at each clock is a bit confusing for me to interpret. I tried to figure out my ...
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Chaining 25 74HC595 shift registers together

Situation: I am doing a project which requires me to chain 25 74HC595 shift registers together. They ate controlled by an Arduino microcontroller. Question: Will it work when chaining that number ...
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Fuzzy digits when driving with TPIC6B595

I designed a schematic and PCB of a simple Nixie clock and I hope that someone will be able to explain what's happening. The problem is that when I'm driving the cathodes with TPIC6B595 shift ...
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218 views

74HC4094 vs 74HC595

I'm planning a large display board where I'll have to display 150 7 - segment digits. Which shift register is preferred here? 74HC4094 or 74HC595 or something else since I'm planning to chain these ...
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52 views

Detect a sequence inside a bit stream

I was recently in a discussion with my professor in which he told me that 'absolutely in no way would this design work'. I am hoping I could bounce it off you guys. The question asked to design (in ...
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60 views

What circuit will output a short latch pulse when the clock input pauses?

I'm transmitting serial data across a cable to a shift register. I transmit data in discrete packets, where different packets have different bit lengths. The clock frequency is about 20 MHz while ...
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Is there a 16 bit version of the 74HC165 [closed]

Basically 16 bit parallel - in, then shift out, HC family. Or do I need to just chain two 8 bit shift registers together?
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Driving Multiple LEDs with the Help of Shift Register

I am using this Shift Register. My circuit is the same as the Figure 14 in the datasheet. I am trying to understand how the data flows from the MCU Serin, Serout lines and how the LED are driven. ...
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Shift Registers for generating codes

can you explain me in simple words how does a linear feedback shift register work for generating a code? Consider for instance this scheme: If I have understood it correctly, each block is a D Flip ...
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Shift Register Concerns and Not Working

I am learning how to use the IC 74HC595 in my circuit and seeing how to make a simple 8 LED output with 5 buttons for pins 10-14 (which control the LEDs). The LEDs I am using for the circuit run well ...
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Switching between sequence different sequence lengths in pseudorandom number generating

I was reading Use Readily Available Components to Generate Pseudo-Random Binary Sequences and White Noise, by Art Pini, to understand generating pseudorandom numbers. I understand that broadly ...
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Easiest way to get 36 -12V sources? [closed]

I'm using the SN74HC595 to drive 36 LEDs (industrial, with internal current limiting), except the LEDs (which aren't substitutable) are common-anode, so I'm using 36 MOSFETs to handle that, like so: ...
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Partial switching of multiple LEDs using shift registers

I'm working on a hobby project where I have 4 groups of 16 LEDs (with a \$V_f\$ of 2.0V). I'm already past the point of putting the LEDs in parallel, since the entire circuit is powered by an Arduino (...
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72 views

Delay a clock to give time for the input to settle?

I have a numerical keypad that I want to feed into a shift register to display the last three numbers I have pushed. My numeric keypad has ten lines, each of which connects to a common on a button ...
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100 views

Why do we like LFSR and PN-sequence in FPGA?

Everybody has learnt that we like LFSR in FPGAs because of its simplicity, FPGA like structure. PN-sequence generator is build up from LFSRs. (So we would think that this is FPGA-like generator...) ...
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PISO buffer for the MachXO2

I'm trying to design a "double-buffer" structure similar to that used in UARTs (for receiving). In my case, it is for samples from an ADC. I shift them in, and at some point my logic detects a ...
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How to reduce voltage from shift register to ESP32 MISO pin?

In this circuit I have sensors that are rated for a minimum of 6V connected to a 74HC165 which passes its output to the MISO pin of an ESP32. I was hoping a simple divider to convert the 6V from the ...
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73 views

Digital signal appears to improve with length of wire - troubleshooting multiplexed LED display

I’ve created a 5x5 multiplexed LED display that’s behaving very strangely. It appears to have something to do with the data signal from the micro controller to the first shift register which appears ...
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What is the output type of the 74AHC594?

What is the output type of the 74AHC594 IC? I didn't find the answer in this datasheet. There is stated in some datasheets for the 74594 IC from other manufacturers that the output type is buffered. ...
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Do I need to limit the current on the inputs of a parallel load shift register?

I have a Parallel Load Shift register (SN74HC165) When connecting the parallel inputs, do I need to add a resistor to limit the current? And if so, can I use one resistor for all 8 Inputs in total? ...
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44 views

Using serial-input latches from Pi to drive 24V load (LEDs)

TL;DR: LEDs when 'on' are great, however, they're too bright when they should be 'off'. I'm trying to build a custom, large 7-segment LED display driven by a Raspberry Pi. I'm a coder so the bit ...
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1answer
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Need a simple explanation of a left-right shift register

I'm familiar with basic shift registers. I'm having a hard time understanding the one below. I feel like I'm overthinking it due its complicated appearance. Would it be possible to direct me to a way ...
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179 views

Multiplexing common anode 7 segments using only 2 shift register, darlington array, and transistor

I'm trying to multiplex up to 8 digit common anode 7 segment display using only 2 shift registers chained together in series driven by arduino. So it would need only 3 pins (trying to save up pins ...
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28 views

What could be causing an unreliable output for 3 different IS31FL3731 chips

I have a board that uses the Adafruit breakout of the IS31FL3731 to control 81 illuminated switches. I have some code that runs on an Arduino that should turn all the lights on, but only about half ...
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155 views

74HC595 Shift Register Latch Pin

I'm picking up a weird bug with my 74HC595 Shift Register's latch pin (Datasheet). What do I want to do? I'm essentially trying to visualise the shifting of the bits with the clock constantly ...
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Can a 74HC595 independently enable or disable output pin without interrupting other active pins?

I am doing a project for which I need to expand the IO pins available on NodeMCU. I plan to use 74HC595 for the same, I have a question regarding that as given below. Is it possible to independently ...
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using multiple shift registers

I am using Atmega128 and 8 shift registers 6D595 the ser_out of each register is connected to the next shift register's ser_in so they form a chain. There is no issue with the hardware it has been ...
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LED cube using 74HC595 and 2N2222

So I'm trying to build an 8x8x8 LED cube according to this Instructables. But I'm using slightly different parts: 74HC595 shift registers instead of 74HC164 2N2222 transistors instead of 2N3904 I'm ...
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Shift Register Alternatives

Ben Eater's 8-Bit Computer project calls for 8 "4-bit D-type register". Is it ok to use the CMOS version, the CD4076BMTE4?http://bg-electronics.de/datenblaetter/Schaltkreise/CD4076B.pdf I have heard ...
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Does a FIFO data buffer need to have the data be registered?

I'm trying to implement a 64 bit FIFO Data Buffer in Verilog. My design allows for data to be written at 4 bytes or 1 byte at a time, and I'm simply using two multiplexers with control signals for ...
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TLC5940 SOUT/SIN signal broken after 4th daisy-chained IC

I have a PCB with 5 TLC5940's daisy-chained. The first 4 work fine, but the fifth doesn't work. The LEDs connected to that one just go on at full brightness and that's it. When I measure the SOUT to ...
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Maximum Switching Speed Chained 74HC595

I'm planning to use a set of daisy chained 74HC595s to control a set of 108 mosfets, 3 of them are geographically in the same area (couple of mm apart) and for the sake of modularity should each use ...
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47 views

Raspbery Pi GPIO + 7400 on a keyboard matrix. Source or sink?

I want to run a large switch matrix from a Raspberry Pi GPIO with the usual diode setup. I'm planning to chain some 74HC595 shift registers for the rows and read the columns from the Raspberry Pi GPIO....
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HVGND v.s. GND for HV509

When using a high voltage IC like the HV509, are there any design constraints with regard to the HVGND (pin27) and the logic GND (pin15). By design constraints I mean any isolation from the main ...
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207 views

Transistor count of a shift register

Static RAM requires, as I understand it, six transistors per bit. How many transistors per bit are required for a shift register, of the simple serial in serial out variety? Is it likewise six ...
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170 views

Cascade shift registers driven by single-cycle microcontroller

I'm trying to make a unit in which 4 digits can be updated in a small amount of time from a single-cycle microcontroller (preferably all digits updated within 5uS) My circuit is setup in the ...
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191 views

What's the difference between a hardware register and a shift register?

There are two different wikipedia articles but they don't articulate the difference very clearly. Is the main difference that the shift registry uses a clock?
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Do i need a LED driver to drive 32 mosfets? [closed]

Im trying to use two 16 channel LED drivers to drive 32 mosfets, im not understanding the datasheet about current sinking, maximum voltages etc. Are they meant to drive the LEDs by themselves? ...
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451 views

Shift register using dff verilog

I want to create a shift register using d-flip-flop as basic structural element, code: dff: ...
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2answers
115 views

Shift register led display not working?

I am very new to circuitry and have attempted to make a circuit (only using IC's) which displays 0's and 1's from the shift register as LED's either on or off, and through the use of a 555 timer shift ...
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1answer
69 views

Vertical Farm Automation

I am building a system to automate a vertical farm (specifically watering, lighting, and drying) and am having trouble choosing between a wired or wireless system architecture. The farm is arranged ...
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Can the serial input of a parallel input/serial output shift register be used as an additional input?

Can the serial input of a parallel input/serial output shift register, such as the 74LS165N, be used as an additional input as it were a 9 input shift register? If it works, I think the input would ...
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Maximum Clock Input Frequency Datasheet Confusion

I was looking for an 8-bit parallel to serial shift register to use in a project I am making. Initially, I thought that the 4021 would work perfectly for what I need, however, after looking at the ...
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PN sequence verifier

I have a AD9253 ADC connected to an FPGA. I want to verify the design, so I use the ADC in PN sequence short mode. (See p.28 in the datasheet.) Here is a table (...
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Magnetism and my breadboard

So today I assembled a little circuit to test my new shift registers (74HC595). I took three breadboards and connected them as shown on the drawing here. It is supposed to work as a user ...
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944 views

16 bit DAC microcontroller

I'm currently working on a audio project where I need to play a 16 bit depth signal with a speaker. Right now I'm using an atmega328 for prototyping, two 8 bit shift registers (controlled by the MCU) ...
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Finite State Machine FSM

I understand how to make state diagram and make combinational logic (gates) to get a boolean equation for the next state bits and the output bit, but what is the function of ROM here ?
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Why is my shift register circuit not working?

I would like to capture the state of some push buttons with a shift register (CD4014B). I am trying to troubleshoot and identify if the problem I'm having is hardware or software. Printing the byte ...
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Multiplexing vs shift registers (input)

I'm going to use a microcontroller to read 80 digital inputs (push button switches). I'm wondering (just to understand, I don't have any critical time constraint) if it would take less time using ...

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