Questions tagged [clock-speed]
Anything related to clock signal frequency (a.k.a. clock speed) issues in digital systems.
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Why do Arduinos ship w/ 16MHz crystal instead of 20MHz?
Why do Arduino boards ship w/ 16MHz crystal instead of 20MHz? They are spec'ed for operating at 20MHz, after all.
I guess there are a few advantages to running more slowly (lower power consumption, ...
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How can you achieve decent clock accuracy in microcontrollers (e.g., max 1 second drift in a year)? How do digital watch manufacturers accomplish it?
I am learning with microcontrollers (mostly PIC16/18 and AVR) for some time, making various experimental projects. One of things that I found surprisingly challenging is maintaining decent clock ...
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How is 255 Tbit/s processed in optical fiber communication?
I have never understood how the new record breaking data transfer speeds are achieved in terms of converting from/to electrical and optical signals.
Suppose we have 255 Tbits of data and we want to ...
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How to communicate faster than the system clock
I was reading about the new (ish) Thunderbolt 3 today, and was very impressed by the specced speed of 40Gbps. Then I looked at Intel's latest i9 processor speed... about 4.2GHz max. How can a system ...
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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?...
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How do I set the clock speed fuses on an ATtiny85 when using an Arduino as a programmer?
I'm following this tutorial, programming the ATtiny85 with an Arduino, using it to play some tones (through a piezo speaker). I'm struggling with getting the tones at the right pitch (I'm creating the ...
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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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"Overclocking" an AVR
In AVR datasheets under the Electrical Characteristics section you will typically find a graph like this (this one is from the ATMega328):
I've seen designs that seem to "work" but operate outside ...
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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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HSI and MSI - Applications of two Internal RC OSC in Microcontroller
In a ST microcontroller I'm using there are two OSC's that can be routed to exactly the same hardware and I'm wondering when you would use each one.
Link to part documentation
STM32L496ZG
Excerpt ...
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How does the current processor technology with low clock rates (<10 GHz) deals with mmWave (>10 GHz) technology used in 5G?
What I mean is that most abundant computing processors in market have the clock frequencies in the range of 2-4 GHz and from wikipedia:
As of 2012, the CPU-Z record for the highest CPU clock rate is ...
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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. ...
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How do I calculate needed pixel clock frequency?
If I want to have a resolution of X * Y pixels, updating in frequency f. How do I calculate the pixel clock speed?
Example:
1280 x 1024 @ 85Hz usually have a pixel clock of 157.5 MHz, but how do I ...
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Does anyone know of a microcontroller/DSP with no clock speeds or any oscillators in excess of 1.705 MHz?
I am planning on making a simple electronic device which I might eventually try to market if it works out O.K. Before taking the plunge and trying to mass produce it, I would first try to sell a few ...
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Can faster processors/clocks execute more code?
I am writing a program to run on an ATmega 328 which runs at 16Mhz (its an Arduino Duemilanove if you know them, it's an AVR chip).
I have an interrupt process running every 100 microseconds. It's ...
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Is a 10GHz clock required to drive a 10Gb serial pin?
I am reading about the 10Gb/s Ethernet PHY for Altera FPGAs (datasheet here). I was impressed to know that, at the hardware level, the 10Gb/s is done serially.
Naively, I would think to do 10Gb/s ...
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What does an MCU need to be capable of USB 3.0 communication?
USB 3.0 has been around for quite some time, since it was released in 2008. But you don't see any simple microcontrollers with an internal peripheral that can do USB 3.0.
The Atmega32u4, a simple ...
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Exotic semiconductors for fast digital ASIC
I am researching exotic semiconductors for a digital ASIC with a few million logic gates which should run as fast as possible within a $30 million budget. (Specifically, I need to do a single fully-...
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Does a baudrate in serial communication (USB or RS232) need to be exact?
In serial communication, does the baudrate mean we have to use the exact clock speed or is it a range of speeds that we can use?
and if it's an exact value, how exact should it be ?
for example, can ...
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What determines the maximum clock rate for a CPU?
What factors determine the maximum CPU clock rate? A 6502, for instance, clocks in the megahertz range, while an Intel x64 chip typically clocks in the gigahertz range.
All things being equal, if the ...
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Ways to observe clock signal of an STM32 MCU
Is there a nice way to be able to observe the clock signal in an oscilloscope to validate my settings for clock speed? After setting it to 168 MHz with PLL for an STM32F407VGT6 MCU let's say.
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pic32 maximum external frequency while running from internal 8MHz RC oscillator
I am completely new to PICs and I have never worked with a part as complex as this. In particular, I'm wondering if it is possible to generate a reference clock (REFCLKO in the datasheet) at 11.2896 ...
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Why are DIMMs not equipped with a heat sink like a CPU?
I know that a DIMM is composed of a set of chips that contain control logic managing the decode and prefetching memory operations. According to a product specification, I found that newer RAM works at ...
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Increase Microcontroller frequency and Speed
I am in process of upgrading the micro-controller of our project from Renesas M16C to RX63N. In our current M16C project we use 16HMz crystal. If in the new micro-controller Rx63N if I use the ...
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Relationship between I2C drawn energy / power consumption and data rate
Referring to just what the I2C lines draw, am I wrong thinking that the higher the clock frequency the shorter the time there will be (the same amount of) current flowing through the pullups and thus ...
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STM32F4 : Floating point instructions too slow
I'm working on an audio application on the Nucleo F411RE and I've noticed that my processing was too slow, making the application skip some samples.
Looking at my disassembly I figured given the ...
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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 ...
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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 ...
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Nanosecond interrupt accuracy on a 64MHz microprocessor
I am currently designing a PCB with a 64MHz nRF52832 bluetooth MCU. I have an interrupt connected to this MCU which needs to be detected with 1-3 nanosecond accuracy.
Unfortunately, the 64MHz MCU has ...
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Is there a small (6-pin) DIP I can use to generate multi-MHz squarewave clocks with an external crystal?
I'm building a circuit that I'd like to run at 8 MHz to begin with, but I want to be able to try it out at 10, 12, 16, 20, and, maybe, 25 MHz. I know that many microcontrollers have the ability to ...
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Is a 4/3 clock divider possible?
I have seen designs for digital clock dividers, which can divide a clock frequency by 1.5, 2.5, etc.
But is it possible to create digital logic which divides a clock by 4/3?
For example, if I have a ...
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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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How do I know if my microcontroller clock frequency is fast enough?
I've been using ARM microcontrollers from NXP in commercial products with great success for the last 2 years.
In most of my projects I don't use the PLL to increase the oscillator frequency because ...
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PIC problem: Touching the crystal capacitor makes the system slows down
I am experiencing a very unusual problem (at least for me). When I touch with my fingers, or the oscilloscope probes, on the crystal or it's capacitors, the PIC runs slower...and A LOT slower then it ...
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Clock skew? Good or bad?
So, I've been reading up on clock skew. I came across the fact that clock skew can be incredibly useful, in the sense that positive skew can be used to speed up the circuit by increasing the clock's ...
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ATTiny85 clock speed problem
Using an ATTiny85 and an Arduino loader I created a simple device for turning on an exhaust fan based on a light sensor. The ATTiny85 turns on the fan after activating a warning light and sounding an ...
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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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ATmega - Why is the prescaler factory defaulted to 8?
Why do ATmega (e.g. 328P or 644P) have CKDIV8 (or CLKPS = 0011) factory programmed along with a default internal 8 MHz ...
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What kind of use cases require a 2GHz, 4GHz, 6GHz, 30GHz or 100GHz oscilloscope? [closed]
I have been thinking of buying some oscilloscope for the work I do with Arduino. In my case it would be partly because of some usefulness and partly because it would give me a chance to learn an ...
user64167
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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....
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Is Transmission Line Reflection Frequency Dependent?
I'm currently sending high speed serial over a coax cable. I've got an oscilloscope hooked up (on the load end) trying to watch the clock pulse signal. I've got a 10 ft coax cable with a 12.5 Mhz ...
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Can't run PIC24EP128MC206 at rated speed
I got a PIC24EP128MC206 because of its rated speed of 70 MIPS. (For whatever reason, it is rated in MIPS, while most other PIC24s are rated in MHz.)
Since my understanding is that one instruction on ...
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RPi GPIO speed issue in bare metal
After reading the excellent article on bare metal by David Welch (https://github.com/dwelch67/raspberrypi/tree/master/baremetal), a friend and I are trying to implement a simple GPIO toggle. It's ...
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What is my AHB1 clock rate?
I am working with an ARM Cortex M3 chip (reference manual available here). I'm trying to get the baud rate of my USART communications right. Reading pages 613 onwards, I understand that the value I ...
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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 ...
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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 ...
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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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Why do micro controllers run @ 100's MHz whilst CPUs run @ GHz? [closed]
Whoopie - I've got a Raspberry Pi. When doing stuff it runs @ 1.2GHz and there are Uber overclockers out there who have boosted them to 1.5GHz (with phase change coolers). Today, the cheapest CPU on ...
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Capacitive load - Matching Right Crystal and Caps for oscillator circuit - DS1302 RTC - cut and trim
CL = (C1 * C2) / (C1 + C2) + Cstray
I have a 12.5pf crystal. DS1302 is happy with 6pf.
what is trim capacitors to make him happy using 12.5pf?
12.5-6=6.5pf
(6.5*6.5) / (6.5+6.5) + cstray= 3.25pf + ...
user83582
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Why ATMega328 can't run SPI at full clock speed
Two part question:
In the datasheet on page 168, the best SCK frequency one get get on SPI is \$\dfrac{f_{osc}}{2}\$, why can't this be \$f_{osc}\$?
Also from the datasheet: "When the SPI
is ...
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