A digital signal that goes high and low at a specific frequency.

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1answer
16 views

Updating of a memory cell / synchronization with a clock

I'm wondering how computers actually work on a gate-level. I can see how a storage mechanism could be built from logic gates (e.g. SR NOR latch). What I'm wondering: how do values in memory cells get ...
0
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2answers
22 views

Source synchronous vs Common clock methodology in Physical design

I understand common clock and source synchronous clock. From this link http://referencedesigner.com/books/si/common-vs-source-sync.php. What i do not understand 1) How is maximum frequency attained ...
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3answers
50 views

Creating a +5V/-4V Clock with a PIC Micro

I'm working on a project to drive a CCD array which needs a particular signal with a high of +5V and a low of -4V, changing fairly rapidly. I'm using a PIC18F4620, which as far as I'm aware, looking ...
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0answers
65 views

Is there a way to fine tune the frequency of a crystal oscillator?

I have a cheap alarm clock at home. I notified that it got about 10 min of delay every two weeks (I have to re-setup time again and again). I tear it down and found out it is driven by a crystal and ...
0
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1answer
30 views

Getting Raspberry Pi or Arduino to control three clock hands separately

I want to make an analog subway countdown clock. The idea is to have an ordinary clock with three hands. These hands will point to the number of minutes before the next, second next, and third next ...
0
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0answers
72 views

Is this achievable with a non arduino microcontroller? [closed]

Good day everyone. I'm assigned to work on this project at school but before I take any further steps I want to check on the feasibility of this make. What my fellow students and I are looking to ...
0
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1answer
31 views

AM437x/AM335x Audio clock generation

For some ADCs and DACs I'm using I need a 24.576MHz clock (96kHz * 256). Obviously I can use a low jitter audio clock generator. However, I have a AM335x processor available that claims to have a low ...
7
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5answers
1k views

How do I drive 14.3Mhz clock input from 10MHz?

I intend to use an IC which requires 14.3MHz clock input, but want to drive it from a stable 10MHz source - derived from GPS. How do I turn the 10MHz clock into the 14.3MHz that the IC requires?
3
votes
2answers
146 views

Choosing crystal, strangely narrow requirements in MCU datasheet?

I am making a prototype using the Atmel ATSAM4S2B microcontroller, but I am having trouble choosing a crystal. I need a 12MHz crystal to use the integrated USB module. The problem is, in the ...
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0answers
44 views

What is the necessity of clock signals? [duplicate]

In many articles on the web clock signals are introduced to be "synchronizer signals" in digital sequential electronic circuits, which can cause various parts of the circuit to operate and do their ...
0
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1answer
50 views

How does a clock cycle delay skip a computer instruction?

This is from the Wikipedia entry on Pirate decryption The signals moving between the smartcard and the receiver can be easily intercepted and analyzed. They can be vulnerable to a "glitch" by ...
0
votes
1answer
60 views

How to Sycnhronize STM32F4 Clock with PC Clock

I'm using 3 STM32F401RE to synchronize their clocks. My desired accuracy is of 1ms and even lesser like 0.1ms. This device is connected to PC via USB port. Question 1 : So I would like to know if I ...
0
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1answer
53 views

Precision timing using arduino and external clock

I'm working on a very time limited project (8 weeks). Basically I need to perform measurements and save to memory. 2 identical boxes, 4 hours and no wireless or wired connection. Each box is ...
0
votes
1answer
30 views

Automatic and manual clock managing. Errors with ring counter but not with 4-bit counter

I'm building an 8 bit computer and I've just developed the clock. I used a NE555 (datasheet) with some other integrated (74 series) to manage it. The operator could stop signal from 555 (with a ...
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1answer
57 views

Arduino based clock with 4 pieces 4" 7 Segment LED Displays

I was going through multiple tutorials on how to create an Arduino clock with 7 segment displays. I planned to build one and purchased 4 large (4 inches) 7 segment 1 digit displays. The displays run ...
3
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1answer
60 views

Dividing a clock in Verilog - is it OK?

Dividing a clock down in Verilog is a basic exercise, and there are loads of answers online about how to do it. What I want to know is whether it is OK to use a clock that has been divided down using ...
0
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1answer
54 views

555 timer digital clock

How would you go about connecting a 555 timer to a circuit with a 16x2 LCD display, which is already connected, to create a digital clock that counts the time? Do you have a sample of how this code ...
0
votes
1answer
56 views

DDRx Memory: Memory Clock vs I/O Bus Clock?

When referring to DDR/DDR2/DDR3/DDR4 memories, I am not able to understand the difference between memory clock and I/O clock. As per: https://en.wikipedia.org/wiki/Double_data_rate DDR-200 - Memory ...
1
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1answer
24 views

Confusion with PIC32MX1XX/2xx datasheet information (clock source for USB)

Maybe there are some experienced "wolves", who could help out to clear out confusion about internal/external clock sources. Particularly, I got lost while reading PIC32 family reference manual, ...
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0answers
57 views

clock frequency too high

I have wired up the clock generator below. However, when I attempt to measure the frequency with an oscilloscope, it is far too high and quite unstable. The measured frequency ranges from 12-50 ...
0
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1answer
51 views

maximum clock frequency for a sequential circuit

This is the all question. I thought that because Tcq>Th we will only count Tcq. If we need to know the minimum clock period, we should calculate the duration from the beginning to the output of ...
0
votes
1answer
47 views

Full-wave rectification for clock signal from wall power

I have built this power supply and clock signal extractor exactly as shown: http://electronics.howstuffworks.com/gadgets/clocks-watches/digital-clock4.htm I have double-checked this and the rest of ...
2
votes
1answer
46 views

Making a positive edge clock pulse with a button?

Is it possible to have an input, say a button, that does one positive edge clock pulse? So I want to press this button once and it does a 0->1->0. I can't think of anyway to do it because it changes ...
0
votes
1answer
109 views

STM32F4 clock behaves very strangely

I can not find a solution for why STM32F427ZIT6 clock changes during operation. I am using external 8 Mhz crystal. Should I rather look for a error in software or hardware? I have a little code, ...
0
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2answers
110 views

STM32F4 clock 60Mhz

I want to set my STM32F446 controller his clockfrequency to 60MHz. I thought I could do it, but without results. I am using an STM32F446 -nucleo board. I used STM32CubeMX to generate my code. After ...
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0answers
88 views

STM32 if-statement timing

I'm working on a porject where I need to communicate with an USB PHY chip. I am using a STM32 microcontoller. (stm32f446ret6, ...
0
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1answer
48 views

Digital Clock - set time x hours ahead?

I have a digital clock made from an electronic kit - it has 3 buttons (1 to set the time, 1 to set alarm, 1 to cancel the alarm). I want to be able to set it so every time it is connected to power ...
1
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1answer
118 views

Need Help In Creating and Debugging a 8Mhz CLK Circuit

I want to create a CLK generator circuit that will work at 8Mhz. I'm following this design (from http://www.electronics-tutorials.ws/oscillator/crystal.html): My crystal is 8Mhz HC49/US, with 20pF ...
3
votes
1answer
70 views

Why is my VHDL clock signal so far off from what I thought it would be?

I'm new to FPGA and VHDL. The following code was supposed to be 5MHz but I'm getting 4.167MHz on my scope. The FPGA board I ...
2
votes
1answer
42 views

In which physical unit is 'clock drift' measured?

I would like to model a clock signal with an drift parameter in my digital simulation. The current implementation handles: frequency / period phase -360.0 .. 360.0 degree duty cycle 0.0 .. 1.0 ...
-1
votes
1answer
92 views

Clock and data vs rx and tx communication

I'm working on a project in which I have to make two pic10f200 microcontrollers communicate via serial communication lines. I know that with Arduino you interconnect the two board's rx and tx lines, ...
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0answers
53 views

Cycles lost on clock domain crossing

I have a MAC (VHDL) connected to the PHY through RGMII (so the clock for this communication is 125 MHz). The MAC outputs every byte at a rate of 200 MHz, so there is some clock domain crossing here. ...
0
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1answer
68 views

frequency divider by 42 with 50% duty cycle

I want to design a clock divider by 42 from flip flops. Is there a way to do that while still gets 50% duty cycle?
0
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2answers
116 views

GPS 1 PPS Aligment Clock Signal Generator

i want to do GPS 1 pps aligment clock signal generator. Clock signal should be at 24.576 Mhz and voltage level Vmax= 3.3 V and Vmin=0 V DC. How can i do that? It is very important to align between GPS ...
0
votes
4answers
130 views

How to generate edge-triggered pulse

First, a bit of background: I am just a hobbyist with electronics and have very little formal education in the area. I understand most terminology, but generally require a schematic for me to be able ...
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3answers
197 views

Understanding Test Parameters on Datasheet (CL pF)

On Page 7 of the datasheet for M74HC590 It uses a CL (pF) At the bottom of Page 8 is the test circuit which shows where the CL(pF) goes, in regards to a circuit diagram, but I don't understand that ...
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0answers
68 views

Nixie Tube Clock Kit Issues

I recently purchased the Lena kit from Nixiekits.eu http://nixiekits.eu/Laura+Lars.htm The manual: http://nixiekits.eu/Downloads/USB_Nixie_Clocks_Aufbauanleitung.pdf After putting it together ...
4
votes
2answers
399 views

How to generate high frequency clock with high stability from a microcontroller?

I am using TivaC launchpad TM4C123G microcontroller, to generate a clock of 40 MHZ but I tested it on the oscilloscope and it doesn't look like a square wave it's more like a sinusoidal here is a ...
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0answers
63 views

I get error in vivado when I try to use source clock of generated one

I want to have two clocks in my project. One that sends output to a VGA and runs at 25 Mhz and another which runs my mandelbrot set calculation at a higher frequency. Here is the code I have. ...
0
votes
1answer
134 views

Output 48MHz system clock on a GPIO pin other than MCO pin on STM32F030

I want to output the max 48MHz clock signal of STM32F030 to drive another subcircuit. The problem is the chip STM32F030F4P6 (TSSOP-20 package) I prefer to use a GPIO because the MCU doesn't have the ...
4
votes
2answers
735 views

Can I produce a square wave(basically a clock) from a USB port on my Laptop? If yes how?

Can I produce a square wave(basically a clock) from a USB port on my Laptop? If yes how ? Briefly explaining, I am using ad9834 in a project and this chip needs a clock of any frequency ranging ...
0
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2answers
82 views

10 USB Hub ICs from 1 Crystal Oscillator?

I am designing a PCB with 10 individual USB hub ICs onboard. They all require a clock input and I am wondering if it is possible to drive all the clocks from a single crystal oscillator? The hub IC ...
0
votes
1answer
99 views

Strange ADC sampling frequency / clock frequency on STM32F401 board

I use a timer to trigger ADC sampling on STM32F401, and the interrupt service routine of ADC will toggle a GPIO pin so that I can measure the ADC sampling frequency using an oscilloscope (which should ...
0
votes
1answer
61 views

How to set SD card clock frequency between 100 kHz - 400 kHz

I am interfacing a 32 GB microSD card with PIC32MX795F512L. I am following the examples provided in Lucio de Jasio's book. As the author has described that to set a 250 kHz, they are ...
2
votes
0answers
40 views

Does sequential clock gating useful? [closed]

I know there is clock gating method that xor-ing the input and output of FF, and use that signal as clock enable. (figure 1, i'll call it xor-ing from now) I'm now studying sequential clock gating. I ...
1
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3answers
137 views

How to delay a “not gate oscillator” to make it run at a desired frequency?

I want to blink an led(0.75 seconds on and 0.75 seconds off) repeatedly. I was thinking of using an idea from a book called "But How Do It Know" by J. Clark Scott. A part of the book tries to explain ...
3
votes
1answer
132 views

Xilinx clocking wizard - How to connect clkfb_in and clkfb_out

I created a VHDL design which needs a 50 MHz clock input. The Spartan-6 I'm working on gives me a 100 MHz clock signal, so I used the Xilinx Clocking Wizard to get a 50 MHz clock. When I choose "No ...
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2answers
132 views

if else statements

I am trying to understand how if else statements and clock work. My application accepts chars as input (), and for each char the application should go into the if else statement. Here the code: ...
2
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1answer
26 views

LPC1110 confusion about default system clock and uart baud rate

I'm trying to get acquainted with ARMs on example of LPC1110 device. And there is some confusion about selecting baud rate for UART. I suppose it is running at ...
6
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0answers
792 views

Why is there a need of external clock even though MCUs can provide timing? [duplicate]

Why is there a need sometimes for an external crystal, even though the MCU have an internal oscillator? To give you an example, the Atmega328P used in Arduino Uno has an internal 8Mhz internal ...