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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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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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41 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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42 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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24 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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43 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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55 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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2answers
53 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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98 views

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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78 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
62 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
47 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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1answer
40 views

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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58 views

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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78 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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52 views

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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4answers
280 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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1k views

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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111 views

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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341 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
120 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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1answer
107 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
243 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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2k views

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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105 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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2answers
72 views

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
96 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
264 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
107 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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1answer
61 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
103 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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2answers
199 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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1answer
74 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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2answers
87 views

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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1answer
76 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
66 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 ...
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1answer
975 views

How do I implement a sequence generator using a universal shift register?

How can I implement a sequence generator that generates the following sequence 0000 1000 0001 0011 0110 1101 1110 1111 using a universal shift register? The shift register I need to use is the 74LS194 ...
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2answers
129 views

Designing of Serial-in/Serial-out Shift Register using RAM

Design a 1024 bit serial-in/serial-out unidirectional shift register using a 1K × 1 bit RAM with a data input Din, data output Dout and control input READ/WRITE'. You may assume the availability of ...
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77 views

Multiplication implementation in Xilinx VHDL

I've been trying to develop a small multiplication engine using some shift registers on XilinX and some custom made functional blocks. The numbers to multiply is Z and T. The purpose of the engine ...
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93 views

SN74HC595N Seems to misread bits

A prenote; I'm not sure if this falls more into electronics or Arduino, but I think Shift Registers are more so electronic and binary related. I'm using a single SN74HC595N shift register connected ...
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43 views

Propagate data bits with 8 BIT register in ISE SR8RLED

I had some issues propagating the input from the 8 BIT register to the output using the SR8RLED 8 BIT Register in Xilinx ISE. The register has the following parameters: ...
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1answer
373 views

Is my SPI multiplexing design correct?

I want a RPi to act as a SPI master and be able to communicate with 24 SPI slaves. The SPI connection is full-duplex. The SPI slaves are about 50 cm away from the master (SPI runs on wires to an other ...
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2answers
107 views

Bus tapping in Xilinx ISE for 8 bit to 16 bit conversion

I have a processing unit which is controlled by a sequencer/control unit. The agenda of this processing unit is to multiply 2 numbers using 8 BIT registers using the bit shift and add method. Once ...
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4answers
119 views

Shift Register over long distances

I am using a SN74HC165 Shift Register to read the signal from some switches. With the SN74HC165 Integrated Circuit near to the microcontroller the circuit below works perfectly. But physically I have ...
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2answers
172 views

How to 'Shift in Parallel' in a shift register?

I am trying to design a basic calculator that can add, sub, mul and div with Logisim. To store the operands I am going to use shift registers. I have recently learned about them and I understand what ...
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1answer
110 views

8bit shift left register with serial in, serial out implementation in verilog

I took an example from website that describes 8bit serial in serial out shift left register. ...
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2answers
280 views

VHDL 4-bit Shift-and-Add Multiplier Buffer and Out port error

I am working on a creating a 4-bit Shift-and-Add Multiplier. I am getting this warning message - "WARNING:HDLParsers:3555 - "//filer1.egr.msu.edu/samarar1/ece230/Project05/Project05.vhd" Line 220. ...
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1answer
49 views

Does the constant on an LFSR primitive polynomial hold any significance?

For the following internal feedback LFSR defined by the primitive polynomial: $$X^3 + X + 1$$ Does the constant at the end do anything to either its pseudo-random number generation sequence or to its ...
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3answers
210 views

Controlling 13 outputs with a mcp23017 or 74hc595 and two uln2003?

I need to drive 13 20ma (constant) loads with a single microcontroller with only 5 available pins. My first thought was to just use a mcp23017 or some 74hc595's but after reading the datasheets it ...
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44 views

I need a universal shift register with a seperate output clock

I tried the 74595 and the 74299 shift registers. The 74595 has a nice feature which is the separate D flip flop register that feeds the output with a separate clock. but it lacks parallel loading and ...
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1answer
54 views

How a register shifts information to right at positive egde of clock

We have given the following question: Design a 4-bit, shift-right register with D flip flops, and use two of these registers to implement a circuit that detects the sequence (x1,x0)=3,0,2,1 (the ...