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Questions tagged [clock-speed]

Anything related to clock signal frequency (a.k.a. clock speed) issues in digital systems.

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2
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2answers
705 views

interfacing multiple ADC: sharing master clock

My project involves interfacing two analog-digital converters to an STM32F411RE microcontroller. The first ADC is an ADS1191, the second is an ADS1158. Those two ADCs will have to convert signals ...
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2answers
306 views

Can I use a button in place of a clock crystal?

So basically, I'm wanting to finally get into electronics. A little while ago I bought a few MCP3008 chips and analog pressure sensors. I've been wanting to build an compressed air system with it. ...
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2answers
325 views

Bus clock and prescaler of an ADC

According to my text book "A clock pre-scaler is needed for ATD module's internal cock (2 MHz conversion clock) to be configured to within the specified frequency range (500 kHz to 2 MHz) for ...
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3answers
3k views

How to measure Clock frequency of PIC?

I am using PIC micro controller (PIC16F1846) with an external 8MHz crystal attached to the external clock pins (RA6 and RA7). Why is it that when I use my oscilloscope probe to attempt to measure ...
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1answer
1k views

stm32L0 - can I use LSE clock for 1ms tick and use HSI for systick?

I am using STM32L051, our task has two requirements for clock management: Need to be running under 16Mhz or higher frequency (thus we use the MSI/HSI for Systick) for fast task processing. Need a ...
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1answer
174 views

Is there a wire (a bus), albeit a very short one, between the CPU and its level-1 cache?

I was wondering what is the specific connection mechanism between the CPU and its level-1 cache so that in practice level-1 cache access time is reduced to match the CPU clock frequency? Do level-1 ...
2
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2answers
7k views

What is default Clock Frequency for Atmega8

I was upto use the UART of my Atmega8 but when i looked at the formula for UBBR, it asks F_CPU(frequency). I have made my own board and havent connected any external clock so what is the frequency my ...
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2answers
13k views

What generates the clock signal in a fast CPU and how does it work?

Often, for integrated circuits, a quartz crystal is used to generate the clock signal. However, this only reaches speeds in MHz. What component, or what circuit, generates signals up to 5 GHz ...
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0answers
218 views

How can we compare processing times of two designs implemented on different FPGAs? [closed]

How can we compare two different designs that perform same task (e.g. processing a 256x256 image) and both implemented on different FPGAs, in terms of processing time(seconds)? For example one of ...
2
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2answers
5k views

Why does increased voltage increase processor performance

When you increase the voltage into a computer's CPU it increases the clock speed of the processor and can lead to better performance. Why does the increased voltage cause the processor's clock speed ...
4
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1answer
342 views

Pull up resistor in NMOS logic value

For my senior high school project I decided to build a basic CPU from discrete components. I plan on using a 5V logic level and the current design calls for around 2000-3000 N-channel MOSFET ...
0
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1answer
331 views

Zedboard clock cycles analysis

Based on the example in here, I tried a very similar example (but instead of multiplying two matrices I just multiply all the elements in a matrix by 2.0). However, when comparing the results of ...
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4answers
8k views

Generate an 40MHz Clock on an FPGA with 100Mhz clock

I'm trying to generate a 40MHz clock on a 100Mhz FPGA and I find it a kind of struggle using Verilog code. I redirected the clock to a pin to check the 100Mhz functionality: ...
0
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1answer
444 views

How fast cpu clock do you need to control camera?

I'm making a camera system with CMOS image sensor and micro controller. But I don't know yet how fast cpu clock I need. Assuming that I use 5MP cmos image sensor and take just still image with 1fps, ...
0
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1answer
213 views

DDR2 data rate and data bus confusion

I am reading on DDR2 memory from past few days and have got confused with some of the terms involved. I am mainly confused from discrete memory (single DDR2 memory IC) rather than DIMM module which ...
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1answer
168 views

It is better to have a negative clock skew?

Is it better to have a negative clock skew? Why? If we compare it with a positive clock skew, which is better?
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3answers
32k views

How to calculate the time of one single tick on microcontroller

I have been in Embedded system for 8 months. I have worked application part more compare with low level. I have basic questions on systems ticks, How to calculate the system tick of Timer, if I am ...
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2answers
591 views

getting the right frequency on XMEGA

I've wrote a small program that runs on an XMEGA : ...
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3answers
1k views

100 Mhz clock frequency for a 16 Mhz MCU

I would like to ask what will happen if I set, for example, 100 Mhz as a clock frequency for a MCU, which can operate at maximum speed of 16MHz. Why wont it work?
0
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1answer
208 views

Clock : CPU clock vs Pipeline Clock Vs Memory Access Clock

A few days ago, I implemented a multi-cycle unpipelined soft-core on a FPGA. It worked like a charm. The FSM beautifully orchestrated FETCH->DECODE->OPER1->OPER2->OPER3->ALU->MEMORY->REG WB->PC UPDATE-...
2
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3answers
1k views

Reduced clock speed with flip flop

My question is if there is a way to reduce a clock to two thirds of its speed using flip flops because i know a flip flop cuts its speed in half.
3
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2answers
2k views

How to check frequency of MSP430 clock?

I'm working on a project in which an MSP430 is used to provide the timing for some stuff where accurate timing is important (it can be off by 10%, but not by 2x). This is driven by the timer A0 ...
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2answers
599 views

XMega Get Clock Speed

I'm doing some debugging on my project and I need to check if I'm setting my external crystal correctly. I have the ability to print out to a serial monitor via usb, is it possible to retrieve the ...
0
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1answer
222 views

How to select external crystal in atmega162

How to set AVR to select external crystal for clock? A _delay_ms(1000) is producing a quick beep however it should produce 1 sec beep if it is operating on 12Mhz. Could it be done programatically of ...
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1answer
236 views

How to compare processor speeds based on architexture

Is there any rule-of-thumb for comparing processor speed based on architecture? I'm researching single-board computers, and I'm trying to compare ones using ARM processors (e.g. Beaglebone Black, ...
0
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3answers
824 views

Can a CPUs speed be increased by (physically) upgrading the CPU clock?

I don't know much about CPU operation, but I'm learning. I read somewhere that making a CPU work faster is as simple as increasing the clock speed (one method among many), and that the real limiting ...
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2answers
2k views

64bit vs 32bit processor execution equivalence [closed]

I'm not sure if I am in the good site but here's my question : I was questionning myself, what would be comparable(execution speed) between a 32bit and 64bit processor. Like what would be the ...
2
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1answer
5k views

Ethernet: Why is the link status “down” when there is a speed mismatch?

For any networking (ethernet) equipment, the link status (layer 1) is down when there is a speed mismatch between two ethernet interfaces (say: one is 10 Mbit and another is 100 Mbit). Is it ...
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1answer
4k 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: ...
3
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2answers
617 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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2answers
2k views

Why long pipelines are preferred over high CPU clock?

Why modern CPU vendors prefers increasing the maximum length of the pipeline over increasing the clock? Accordingly my understanding, increasing either increases the number of gate switches and so ...
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4answers
476 views

Best way of confirming system clock of controller

I would like to know the tricks or hints which could be used to find the system clock of 8 bit micro controllers. What are the cool ways in which we could find the system clock and can be verified ...
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1answer
2k 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 ...
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2answers
110 views

giving a lower clock rate to circuit in system generator [closed]

I want to give a lower clock rate to my circuit in System Generator. Can any one help me in this manner?
2
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1answer
7k views

Arduino clock speed prescalers at start without fuses

I know it's possible to change the clock prescaler at runtime. But is there a way to set the prescaler that is used at boot on an ATMega328? I'm aware of the fuses, but those are pretty permanent. I ...
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2answers
2k views

Microcontroller requirements for TFT display

I want to know if I can drive this 320x240 TFT display: http://www.buydisplay.com/download/manual/ER-TFT032-2_Datasheet.pdf Which has this controller built-in with 168KB dedicated RAM: http://www....
1
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1answer
636 views

How the delay locked loop (DLL) align the clock?

The delay locked loop is used for align the clock in integrated circuits. In the IC there are no of flip flops and other devices. I want to know that how the DLL align the no of clocks going to ...
3
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5answers
10k views

How to check PIC system clock speed MCU?

The entire project depends on this, so I just want to make sure I have it right. I'm using a 20MHz external resonator and putting that through the PLL in hopes of getting an F_SYS = 120MHz. Without ...
1
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1answer
151 views

Error in dsPIC33 Family Reference Manual Oscillator?

I'm using an external 20MHz (categorized as high-speed or HS range) resonator and using PLL, but I'm not able to clock the device up anywhere near the max cpu speed advertised. How are you ever ...
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1answer
1k views

minimum clock cycles needed?

The instruction call Rn,sub is a two word instruction.Assuming that PC is incremented during the fetch cycle of the first word of the instruction,its resister transfer operation is ...
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2answers
3k views

Output Data Rate for this gyroscope is way lower than the clock rate?

I was planning on using an L3G4200D gyroscope in a project to align manufacturing rollers. I've been looking at the datasheet and it says that the clock rate is 10 MHz but it also has something about ...
6
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1answer
2k views

Is CPU/GPGPU heat dissipation quadratic in clock frequency?

In the following article on overclocking a Pentium from 1GHz to 5GHz using liquid nitrogen: The 5GHz Project, there is an assertion that "Heat dissipation rises exponentially during extreme ...
9
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1answer
7k views

Maximum clock frequency of microprocessors

Recently, I have heard that AMD has released the new Vishera series of FX processors which run at 5 GHZ. My question is whether there is any upper bound of clock rate of a processor? That is can we ...
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4answers
10k views

Making a clock spin faster

I'm pretty new to electronics and hope that this is the right place to post this. I want to take a battery powered analogue clock and make the hour and minutes hands spin faster. I want to make it ...
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2answers
297 views

Pipeline question

I'm having trouble with this question. Assume a 5-stage pipeline and a 200 picosecond clock time. what is the time required to execute one instruction? assuming the pipe is kept full, how ...
2
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1answer
468 views

LCD displaying only cursor but not characters after clock change

I am using a 20x4 LCD on PortC of an ATmega32. I have disabled JTAG and I am using the LCD library by Newbiehack.com. Until recently everything (characters included) was displaying fine. Then I ...
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2answers
7k views

AVR interrupt service routine not executing as fast as expected (instruction overhead?)

I'm developing a small logic analyzer with 7 inputs. My target device is an ATmega168 with a 20MHz clock rate. To detect logic changes I use pin change interrupts. ...
15
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2answers
8k views

How can a CPU dynamically change its clock frequency?

My Intel CPU changes clock speed depending on the usage, but how does it decide what clock speed to run at? Is the clock speed determined by the OS software using an algorithm, or is it hardware based?...
2
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1answer
917 views

Determine suitable clock speed?

I want to learn about good techniques on how to choose the suitable clock speed for the microcontroller for a project. For example i want to create a device with a pic16f877 microcontroller that ...
2
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1answer
351 views

Limitation of baud due to propagation of voltage over distance

I need to make sure I have my facts straight here; the math works but I may be missing something: In a 100BaseTX network over Cat-5 copper, each party has a circuit (one twisted pair) on which they ...