Questions tagged [clock-speed]

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

Filter by
Sorted by
Tagged with
0
votes
1answer
112 views

Calculate C and R in a CMOS Crystal Oscillator

I stumbled over this simple solution to drive a crystal oscillator, but I need to connect a 25.17MHz crystal instead of the 10MHz in this schematic. How do I calculate R1 and C for a given frequency f(...
0
votes
1answer
373 views

Codec in 'master mode' require more than one external clock? (MCLK?) to drive I2S system timing to/from MCU slave?

Does an audio codec in 'master mode' require more than the one clock line (MCLK?) to drive and time I2S data sync to MCU or FPGA slave? I understand that the I2S proper consists of three lines - '...
2
votes
3answers
4k views

How to configure Atmel SAM D20 for internal 48MHz clock source?

I try to run a Atmel SAM D20 MCU at 48MHz using the internal oscillator (OCM8M) and the digital frequency locked loop (DFLL48M). All I achieve is a deadlock of the processor, even I use a simple "...
-1
votes
1answer
76 views

What is Symbol Clock Frequency?

I came across the term Symbol Clock Frequency in this Intel programmer reference manual (P131). I could not find what the symbol clock frequency actually is in the manual or online and thought it ...
1
vote
2answers
239 views

High frequency clock from clocked RS latch

We were taught that this circuit is not of much use as when CLK=1, J=1 & K=1, Q toggles at a very high rate. So suppose I want to make a high-frequency clock, can I use this? Of course, the ...
0
votes
1answer
429 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 ...
5
votes
2answers
421 views

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.
2
votes
5answers
115 views

Little change in Verilog module results in high change in power consumption (Synopsys Design Compiler)

I am comparing two Verilog designs: Design (1): A top module that is driven by a clock running at 50MHz, which is the main system clock. Design (2): The same top module as in Design (1) with one ...
1
vote
1answer
58 views

Find critical path and maximum clock frequency in digital circuit

I have this problem: Consider this circuit: Find and describe the critical path. What is the maximum clock frequency? MY ATTEMPT Okay, this is how I see the critical path: DFF -> G1 ->...
1
vote
1answer
59 views

Oscillator slows down when my hand hovers over it

I'm teaching myself VHDL using this MAX II CPLD board. I designed a frequency divider and 4-bit counter in VHDL using the onboard 50MHz oscillator. It seemed to work as the onboard LEDs are flashing ...
1
vote
1answer
100 views

How to synchronize PIC PWM clocks?

I'm considering a design which has multiple PIC-based controllers producing PWM signals at 31 kHz. Sometimes, under a well-defined "handover" condition, some pair of PWM power feeds will be connected ...
7
votes
3answers
29k views

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 ...
4
votes
0answers
120 views

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 ...
1
vote
0answers
30 views

How to pick clock speeds for a CS4270 codec?

I'm in the process of designing a circuit which includes a Cirrus CS4270 codec and a STM32F405 running as a DSP. I'm trying to define my max usable settings, which would be running at Fs = 192kHz. I'...
10
votes
2answers
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 ...
0
votes
1answer
116 views

WAVGAT Pro Mini, no serial output

I ordered some Pro Minis however get some WAVGAT clone thingies. The first problem was it is running too slow (4x slower) when compiling with default "Pro or Pro Mini" board profile. Serial however ...
-3
votes
1answer
46 views

How to compute clock cycle time from given frequency

let's say I have a processor runs at 100MHZ frequency how can I compute from this it's clock time for each cycle? I know that Frequency = 1 / Clock Time but I am having trouble to fully understand how ...
0
votes
1answer
249 views

Asynchronous FIFO in clock domain crossing

Clock domain crossing issue can be solved by using asynchronus FIFO with input frequency f1 is of the source domain and f2 is of the destination frequency. If the data is sent in bursts, depth can be ...
3
votes
0answers
119 views

Increasing system clock frequency on STM32F303 drops I2C clock proportionately - why?

I'm trying to figure out a weird little issue I've discovered while debugging another element of my code. I've got a STM32F303K8 reading and writing to an I2C peripheral. The I2C clock speed is ...
22
votes
4answers
4k views

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 ...
0
votes
1answer
64 views

How to set up clock for the STM32 Nucleo-64 with libopencm3/rtos

I was using this code from github on a blue pill. Now I would like to adapt it for STM32F401 on a Nucleo-64 board. I tried changing the GPIO to A7 and attaching an led (which lit up when I attached it ...
5
votes
3answers
5k views

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 ...
1
vote
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
votes
1answer
79 views

How can I create a long (10 second) pulse from a short active pulse?

So let's say I have an incoming signal: 1 clock cycle from a ~1-100 MHz (50 MHz for this example) clock domain. And I want to drive an output that must be active high for 10 seconds for each time the ...
0
votes
2answers
48 views

Clock Generation from Oscillator

Is there specific standard ways to generate clocks from oscillators? Referring to generating a square-wave clock from a sinusoidal oscillator output. I can think of a few circuits involving diodes as ...
0
votes
1answer
62 views

Sleep vs low frequency

Some processors have a low frequency mode for using in low power mode. For example MSP430 microcontroller can work in both Normal clock frequency 16M Hz Low clock frequency 32 kHz I am wondering if ...
1
vote
2answers
123 views

What is the significance of 111 in clock speed?

Never really thought about it until recently, but it looks like the number 111 appears very frequently in clock speeds and such: the first example that comes to my mind is one of the handheld game ...
6
votes
5answers
1k views

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 ...
3
votes
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 ...
0
votes
1answer
270 views

How to query APB1 clock frequency?

I'm trying to query the current value of the APB1 clock frequency to input into a USART configuration. Ideally, I could just query whatever the USART2 clock source is on an STM32F302xx, in case I ...
0
votes
1answer
101 views

Micro controller clock speed requirement for delay measurement

I am trying to measure the absolute time between two 1Hz clocks (GPS PPS events) to within 50 nanoseconds. I do not necessarily care which clock occurs first, I am only looking for the delta T between ...
0
votes
3answers
444 views

Simplest shift register test circuit - clock

I'm looking for the simplest way to test the operation of a 74HC595 shift register without complex circuitry. Currently (on a breadboard) I have a 47K SIP resistor in a pull-up fashion connected to ...
-1
votes
1answer
196 views

SPI clock selection

Using STM32l476 controller. Master is running at 30 MHz and slave is running 15 MHz. In SPImaster, clock should be system clock/2. In slave, clock should be system clock/4. Question: My ...
2
votes
2answers
798 views

How to use 1PPS to Synchronize ESP32 Clocks and Peripherals

I've read a few posts (example) about what the 1PPS signal is and how it can be used at a high-level, but I'm still not sure how to actually implement it on a PCB schematic to sync up with my ...
4
votes
5answers
2k views

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 ...
0
votes
1answer
372 views

ATtiny13A cannot be programmed anymore with Arduino as ISP at 500 Hz

My ATtiny13A fuses are set to use the internal 128 kHz clock without clock divided by 8. I found online an ArduinoISP sketch that allows me to program it with that clock speed. But then I uploaded ...
0
votes
4answers
96 views

Could we theoretically massively increase number of parallel computations (for some problems) by getting rid of cpu clocking?

CPU clocking involves making sure that each operation or part of an operation takes exactly a certain amount of time (the machine cycle time). One way to increase the efficiency of a cpu is by ...
0
votes
1answer
109 views

Have I bricked my ATMEGA3328p by setting

I was playing around with setting the "system clock prescalar" (CLKPR). I'm now in a situation where I can see that the clock is 244.9KHz, using my logic analyser and the "Clock output on PORTB0" ...
0
votes
1answer
289 views

What are the advantages of a wider bus in comparison to those of a higher clock frequency? [closed]

The aim is to increase data transfer rate. I understand each may have some drawbacks and advantages. Frankly I'm not knowledgeable enough to know of many so I'd like some input from others. I know ...
2
votes
3answers
914 views

(TDC) Time to Digital Converter for (TOF) Time of Flight Applications. 66.6Picosecond sample

Hello. My question is in regards to dynamic range of short time period TDC's. or alternative solutions to a time to digital application. if further information is required, please ask. Notes ...
0
votes
1answer
410 views

Slow clock speed with Atmega328P AVR microcontroller on breadboard

I have a small breadboard with an Atmega328p 28 pin microcontroller with a 16 MHz crystal and two 20 pF capacitors on it (similar to this demo: https://www.arduino.cc/en/Tutorial/ArduinoToBreadboard). ...
0
votes
2answers
387 views

Overclocking an image sensor for higher FPS

What happens if I overclock an image sensor? For instance the OV7670 (datasheet) which has a rated maximum system clock input (XCLK) of 24 MHz and maximum pixel clock (PCLK) of again 24 MHz. The ...
7
votes
4answers
656 views

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-...
0
votes
2answers
325 views

ATmega 32 Clock Frequency Issue

I'm currently using ATmega32 device with external clock speed of 16 MHz . the problem when i use a delay of for example 16,000 ms in the software, it actually delays only a 1000 ms in actual world. I ...
3
votes
1answer
144 views

Quartz Clock Accuracy

Do the vibrations of aircraft engines (or any engine, for that matter) dilute the accuracy of a quartz clock? I haven't done any kind of research or hypothesis testing, though I believe that the ...
3
votes
2answers
1k views

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 ...
1
vote
1answer
163 views

LCD SPI clock frequency with STM32L0 MCU

I'm designing a PCB that includes LCD Display NHD-C12832A1Z-FSW-FBW-3V3 (datasheet) connected to the STM32L071KZU6 microcontroller (datasheet). I'm afraid that the SPI interface of the LCD will not ...
5
votes
4answers
2k views

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 ...
6
votes
5answers
4k views

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 ...
2
votes
4answers
403 views

Maximum Clock Frequency

As an assignment for the HDL course I'm taking, I've to design an FIR Filter. The module consists of two a small combinational circuit which can be used to reset the module, another combinational part ...