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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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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72 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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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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47 views

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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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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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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54 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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187 views

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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45 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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30 views

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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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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79 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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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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126 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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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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67 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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135 views

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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620 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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842 views

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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1answer
216 views

74HC595 with no latch pin

If I use the 74HC595 output shift register, and I don't use the latch pin, would it still work as shift register, like the 74HC164, that doesn't have that pin at all? The shift register is going to be ...
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152 views

9X9 RGB Led matrix, design suggestion

I need to drive 80 RGB leds (so 240 individual leds), physically and conceptually aligned as an 8x8 matrix + an additional vertical line and an additional horizontal line. I'd like to drive the ...
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1answer
676 views

Measuring individual cell voltages in a series cells Battery

I'm making a 600V battery, and I'm trying to design a Battery Monitoring system, that measures (and keeps log of) each cell's voltage turn by turn, in a series configuration of 162 lithium cells. 162 ...
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What are the differences between shift register ICs?

I'm learning Arduino and one thing that caught my attention was the use of Shift Registers to expand the number of digital pins. I've seen many tutorials that use 74HC595 Shift Register, but my local ...
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117 views

Using LED display

This is my current circuit. It's a 2 person colour guessing game. The first person will choose the colour code the other player has to try and guess using the registers on the left and then set the ...
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Atmega88p with shift register 74hc595

I need to use a shift register to control multiple leds, but I need to control each one individually. The idea would be to send a buffer with the data, however I need to have several active leds and ...
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1answer
139 views

PISO shift register to USB

I have ~26 parallel inputs that I would like serialize and send to a computer over USB. I decided to chain together 4 LS165 parallel-in serial-out shift registers, but I don't know how I would send ...
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1answer
402 views

How to make shift register logisim

How would i make a 4 bit shift register with d flip flops so that only 1 led is active at once. So for example if a button was pushed the first led would light up and the other 3 would be off. If the ...
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1answer
147 views

Why is serial output from shift register offset from others?

I was debugging my circuit that uses TI SN74HC595 shift registers, which I daisy chained. I transfer data to she first shift register using an Arduino, and SPI library as it is faster than bit-banging....
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100 views

CD4015BE with carry?

My question is about the CD4015BE that i would really want to use in one of my projects, but i can't figure out how to make a carry out for the second register. In the datasheet they mention that it ...
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1answer
129 views

Dim a LED array through PWM on power supply or output enable?

I have an 8-LED array driven by an 8-channel source driver (TD62783AP) controlled from an 8-bit shift register (74HC4094). When it comes to dimming the LEDs using PWM, I came up with two solutions, ...
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283 views

Is it a good idea to refresh a display (8x8 LED matrix in this case) inside an interrupt handler?

Let's say I have an Arduino connected to a 8x8 LED matrix. In my case, the LED matrix is driven using two 74HC595 shift ...
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89 views

8-bit shift register Master Reset button not working

I'm using the 74HC595. The datasheet can be found here. Everything works, just the only problem is the Master Reset button is not working. Pressing it to LOW doesn't do anything. I measured the ...
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Shift register Tri-State and ULN2803A

I was planning to use the SN74HC595 shift register in association with the ULN2803A and MIC2981 to switch on and off some loads based on the data of the shift register. What happens if I disable the ...
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100 views

Partially daisy chain shift registers

Let's imagine a strip of 30 LED, each of those controlled by daisy chained shift registers and a micro controller. I would need 4x 8-Bit shift registers like the SN74HC595, and the last 2 outputs ...
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1answer
68 views

controlling some RGB LED modules with HD74HC254P and 74HC595N ICs

I got some LED modules dismantled from old festival screen. It would be nice to get them working, but I can't find any info about them, neither I have any idea how to controll them. AFAIK they are ...