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

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42 views

register without clk

I'm designing a small system in VHDL using the datapath and contorller method. Is it okay if I design registers that don't have a clock input (load data on the rising edge of the load signal) as they ...
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2answers
27 views

How to give clock on xilinx spartan 6?

I am trying to run a counter on Digilent Atlys Spartan 6 xc6slx45 development kit, which changes counts on clock edge. I am new user to Verilog, so I don't know how to give clock to my program from ...
3
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2answers
279 views

Clock generation on my PCB

I have not a big background in electronics. I am designing a PCB including a MCU (EFM32) and some ICs. I have seen in lots of circuits that they generally add an external Crystal Clock on the board ...
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1answer
61 views

Solid color display on VGA not working

I'm trying to get VGA working on my Altera DE0 board using Verilog, but haven't had much luck. It has the same pins as a normal VGA interface except red, green, and blue are all 4 bits each. Here is ...
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1answer
103 views

Why use STM32 HSE?

Why do we use an external oscillator for STM32??? Why not just use the microchip oscillator? I am using STM32F2xx it clocks at 120Mhz But, an external oscillator of 12Mhz is latch into the ...
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1answer
31 views

How do data and address strobes cause input to be latched?

Often in digital systems when multiple components communicate with each other they use strobe signals. Among these are data and address strobes. The strobe signal being asserted means that the data or ...
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1answer
91 views

I2C protocol debugging using oscilloscope

We are testing an I2C accelerometer connected to the ATMega32A micro-controller. The accelerometer was working fine. We can write and read the registers using I2C protocol. When connected to the ...
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1answer
47 views

Choosing between internal oscillator and external crystal- ATXMega32E5

We are working with a modern microcontroller ATXMega32E5, from the ATMEL XMega family. Our aim is to use the UART of the controller for effective communication, with the speed of about 9600 or 4800 ...
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1answer
47 views

How come the value in my RAM of DS1307 RTC become zero?

I'm using the 56 bytes of RAM in the DS1307 to store some data. My DS1307 is connected to the PIC18F46K22. But after running a few days, all the data inside the RAM will suddenly become zeros. The ...
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1answer
44 views

Verilog: sampling data in both posedge and negedge of the clock

I have a serial input stream which has left data in posedge of the clock, and right data in negedge of the clock. I would like to synchronize and bring them to the posedge of the same clock. I could ...
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1answer
42 views

Delete or ignore I/O from a schematic block in Lattice?

I am programming with a Lattice ispMACH 4000ZE Pico DevKit and with the software ispLEVER Classic Project Navigator. I want to use in my schematic file the OSCTIMER block from the Lattice library, but ...
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0answers
32 views

Wave generator for a certain clock pattern

Refer to the figure above. How can I generate these clock patterns? What waveform generator should I use? I have used this lately (refer to figure below): And my clock patterns are these:
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1answer
54 views

Assembly XMEGA program creating a longer than expected pin toggle?

I'm trying to do the fastest pin toggle possible on an XMEGA32E5 running at 32MHz. My code is as follows: ...
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1answer
49 views

Cable for transmitting 4MHz 3V3 signal

I am building a device on breadboard where there are 2 ICs: a microcontroller and some auxillary IC, they should communicate via SPI with a 4 MHz clock. Because I don't have enough place on my ...
0
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2answers
61 views

How can an input signal to an FPGA be determined as the clock signal?

How can I determine a seemingly arbitrary signal applied to an FPGA to be the clock signal? Conditions: 1. There is no other clock signal available (as an input to the FPGA) for sampling this input.2. ...
0
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2answers
186 views

Porting SPI code from (Intel) Galileo to Edison - Arduino

I'm currently working to port some Arduino sketches from Intel Galileo that use SPI (using a prototype Arduino Breakout board). I haven't been able to get it to work so far - but I have used an ...
0
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1answer
60 views

Why do we need Frequency Divider for external clock (GPS reference signal) for Frequency Counter?

Our senior project is to build a precision frequency counter which is using GPS signal as a reference. I looked up somebody else project online and found that I have to divide reference signal ...
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0answers
41 views

Feed Raspberry Pi camera module with external clock signal

I want to frame synchronize multiple Raspberry Pi camera modules - I guess I can do this by feeding all the modules with a single external clock signal. The thing is being discussed in this post. The ...
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1answer
120 views

Custom built 16x32 (40) LED Matrix controlled by Arduino

I am planning to build a clock / thermometer / info display. I have ordered 10 pieces of 8x8 LED matrixes from ebay (http://www.ebay.co.uk/itm/331064583297). As this is not a pre-built one I have got ...
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2answers
48 views

Building a first State Machine circuit - Technical Help

I just learned how to synthesize a diagram of a finite state machine into a diagram of a logical circuit composed of D flip flops, a clock and logical gates. However, I don't really have much ...
0
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1answer
127 views

50 MHz FPGA (Cyclone IV @ DE0-Nano) and 60 MHz input from FT2232H

I want to read data from FT2232H used in an FT245 style synchronous FIFO mode (http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT2232H.pdf p.27) with DE0-Nano FPGA board: ...
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0answers
37 views

Pipeline Processor Calculation

My assignment deals with calculations of pipelined CPU and single cycle CPU clock rates. The following data is given, about the time each operation takes to execute: ...
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3answers
61 views

Interpreting Crystal Deviations

I am investigating the accuracy of a crystal mounted on a MCU. The API provided by the MCU manufacturer has a TimeGet48 function that returns a 48-bit number ...
2
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1answer
88 views

Clock Ringing/Noise

I'm trying to make a simple 32.768kHz clock circuit. On the datasheet for a crystal that I found, it included the following circuit: simulate this circuit – Schematic created using ...
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1answer
37 views

Clock / timer activated 2 second voltage timer for wiper motor project

Ok, I need a 12 volt voltage timer using clock or timer for a wiper motor. I am working on a project in my garage. Simply put, I am wanting to use a wiper motor that will open and close a spring held ...
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1answer
132 views

counter that MSB toggles every 2 seconds [duplicate]

I want a counter that the Most significant bit toggles every 2 seconds, and gets values 0 and 1.So for example it will have 0 for 2 seconds and after 1 for another 2 seconds etc.. I need it like that ...
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0answers
94 views

Atmega32 can't verify after setting correct fuses for external crystal. HELP

I am having trouble with some Atmega32A's purchased off from eBay. The MCU's does not seem to be fake as they are functioning properly. I am experiencig the following problem: I want to use external ...
5
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2answers
322 views

How do IC's know when there is a downward or upward transition of a clock pulse?

Title pretty much says it all. But how do most IC's, micro-controllers, etc. know when a clock cycle starts a downward or upward transition from the clock source?
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1answer
70 views

CPU and clock rate

As I understand it, CPUs generate electrical pulses using a quartz crystal. The rate the pulses are generated (taking into account various multipliers) give the processing speed which all components ...
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1answer
54 views

Do I need to reset a DDR's DLL when I change clock frequencies?

I have a system that boots at one frequency and then the main PLL is reloaded to continue boot at a higher frequency. When this is done, the DDR is put in to self refresh. After the main PLL locks, ...
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0answers
47 views

How to convert square output of Si5351 to sawtooth when working at 28.8 MHz

I'm going to build a clock generator around the Si5351A chip. The configured output frequency will be 28.8 MHz. The output of the chip can only be a square wave. I've seen some schematics on the web ...
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1answer
250 views

Genlock two OV5642 camera modules on Arduino with ArduCam

I need to shoot stereo video or stills at about 10 FPS possibly in perfect sync. My plan is to set up a 3D stereo rig (2 standalone units - each consisting of Arduino UNO + ArduCam shield + OV5642 ...
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1answer
37 views

Controlling the frequency of oscillation of SI530 VCXO

I am thinking of using the SI530 VCXO as a means to generate clock signal at frequency of 1.4 GHz. But in the datasheet I do not pin which controls the frequency of oscillation. Can someone help! ...
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0answers
42 views

Frequency locked loop for input jitter rejection

I have an application where I want to multiply from a xtal oscillator at 32KHz to a system clock of 40MHz. A standard PLL isn't going to do the job, because the 32KHz jitter is measured in ns. Since ...
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1answer
58 views

Which Clock Would Run Faster [closed]

I have two identical clocks: one is plugged into 120 VAC @ 60 Hz. The other is running on a 12 volt battery. Which would run faster, and more importantly, WHY? Based on my understanding of a quartz ...
0
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1answer
42 views

How to calculate the oscillator capacitor value for a switched capacitor (MAX7405)?

I would like to use an 8-order LPF switched capacitor: MAX7405 datasheet The cut-off frequency can be set by simply connecting an external oscillator capacitor, Cosc. I would like to design a 50Hz ...
0
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1answer
90 views

Exact (accurate) and cheapest Second Signal Generator circuit

Sorry, this is my first question. I want to create a watch (clock) with needles, but I want to create a circuit to generate the second signal (not labview, not software). I need to know the IC's ...
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1answer
151 views

Is 'IF' statement necessary for the clock process?

I'm used to writing the following process that will react on the rising edge of the CLK (script 1): ...
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1answer
71 views

MPU accessing busy memory

I didn't know whether to place this question here or on stackoverflow, but I finally decided to post it here. I want to build a simple system that would be able to work with basic peripherals (UART, ...
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1answer
88 views

How can we find the clock frequency (SCK) set by master from slave in SPI

How can we (in software, no probing using CRO) know what clock frequency the Master applies from slave (assuming I have no prior information of this). In general I program the Div_Reg register and I ...
2
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3answers
58 views

Anyone have specific examples of how IEEE 1588 is most commonly used in industry?

I've run into the concept of IEEE 1588 synchronization over Ethernet several times, and am curious what its most common uses are and the details of why it is required. For example, I read that cell ...
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1answer
99 views

Improper functioning of Timer1 in pic18

I'm using pic18f controller and i am supposed to get a delay of 1 sec.I'm using an external crystal of 16mhz and this is the configuration bits that i have used in it.I have configured the timer1 and ...
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0answers
49 views

Parallel Write On External Clock on STM32

I am using 8 GPIO pins on an STM32F407 for a parallel write to an external device (FT232H). The parallel write is synchronous, ie. I have to synchronize my data to a clock provided. According to the ...
0
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1answer
47 views

For two clocked components in series, how do you ensure that the output of the first is captured by the second?

I'm working through the open Nand to Tetris course offered by Nissan and Schoken. I've just finished chapter 5, where we construct a 16-bit computer using a hardware description language and an ...
0
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2answers
65 views

What is the jitter of an asynchronous FIFO?

I have an asynchronous FIFO (in a Stratix V FPGA) with two asynchronous read and write clocks of the same frequency of 100 MHz. As I understand, asynchronous FIFOs have a two-register ...
1
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1answer
207 views

How to design a two-stage synchronizer with a clock divider in Verilog?

I have a very fast clock called CLOCK_50 which I would like to slow down through the use of a clock divider. The output is ...
0
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1answer
129 views

Why does `RCC_GetClocksFreq` return different results than I expect?

I have a STM32F427 MCU with a 8MHz HSE crystal. I am setting up the clock as follows: ...
5
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4answers
685 views

What is a ripple clock?

I am reading Chapter 12. Recommended Design Practices from the Quartus II Handbook Version 13.1 Volume 1: Design and Synthesis which states (p. 8): Ripple counters use cascaded registers, in which ...
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0answers
156 views

STM32 Timer Internal Clock Source

As I understand, the internal timer clock source on the STM32(F4) microcontrollers can be either APB1 or APB2. However, I can't find which timers get which clock. I already found ST AN4013, which ...
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1answer
70 views

Testing camera framerate variability by filming clock time

I would like to test the framerate variation from nominal value in a range of consumer video cameras. For this I intend to film some sort of high frequency clock and compare the displayed clock time ...