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Questions tagged [clock]

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

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Verifying if HSE is used by MCU as system clock without probing

I have a PCB where I use an 8 MHz quartz resonator as this MCU's external system clock source. In STM32CubeIDE the setting is as follows: The program runs fine in MCU, but I cannot be sure if HSE is ...
cm64's user avatar
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1 answer
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TI LMK04828 , two questions, bipolar or sine wave modes, LVCMOS/LVTTL or sine wave

I am using an external clock source to drive the clocks on an embedded system. This is done by seating an add-on board and then plugging in something that looks like an RF SMA into said add-on board. ...
Ksenia Semenova's user avatar
1 vote
0 answers
27 views

SDRAM Clock routing. Top Layer vs Sandwiched between GND/Power Planes. What's is better for EMC?

Planning a new design, were I finally removing a termination resistor on SDRAM_CLK line. Planning to increase the clock speed to 200MHz as well. Previously it looked like a straight forward decision ...
MMG's user avatar
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What does the standard deviation of TIE measurement tell me about my clock signal jitter?

When we take a Time Interval Error (TIE) measurement of a clock signal, we are presented with two measurement outputs, the mean error and the standard deviation. When I measured the TIE of a 32....
tronhawk's user avatar
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2 votes
1 answer
57 views

Clarification on getting 1 Hz from a 32.768 kHz input using 74HC4060BQ-Q100

I'm working on a project where I need to divide a 32.768 kHz signal down to 1 Hz. I initially thought I needed a Q14 output from a counter, similar to the CD4060 circuit where Q14 is passed to a D ...
Sean O'Sullivan's user avatar
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1 answer
46 views

555 IC - Role of Resistor in Capacitor Discharge (Astable mode)

I can't grasp the role of resistor Ra in this circuit. I know that when the output from the SR latch is low, the transistor doesn't allow the capacitor to discharge. And when the output is high, ...
João Amaral's user avatar
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1 answer
55 views

Problem initializing PLL as clock NUCLEO-H563ZI

I am trying to initialize the clock with PLL as system clock. The code I used is the following ...
gagan chopra's user avatar
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2 answers
54 views

How do clock signal generators prevent race conditions?

With full understanding that wikipedia is not a completely reliable source, this wikipedia article explains that a clock signal prevents race conditions by making components update at the same time. ...
Stressed 's user avatar
1 vote
2 answers
72 views

Designing a particular clock cycle series with glue logic/CMOS/TTL for serial data without a uP

I am looking to design an interface for serial data that runs for 31 cycles (not 32, I know), but with uneven cycles to transmit serial data. Each cycle is 8 clock pulses (at 7MHz). For the first 20 ...
paraparabolic's user avatar
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1 answer
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Lattice MachXO3LF FPGA Internal Clock Accuracy

On the data sheet for the Lattice MachXO3 FPGA family, it shows that the internal oscillator has varying nominal frequencies with +/- 5% accuracy. Does this apply to its entire temperature range ...
user373900's user avatar
1 vote
1 answer
43 views

Trying to figure out rise/fall times for different load conditions

I have a device that requires a certain rise/fall time for its input clock. It specs a .7ns rise and fall time with a 20% to 80% measurement at a Cin=6pf. I should note that the spec rise/fall time ...
Matty's user avatar
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1 answer
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Trying to make an digital clock circuit however can't make it work as intended [closed]

As a project, my professor gave the class to make an digital clock circuit (no microprocessors allowed!). I have used a 555 timer, 6 SN74LS90N and 6 SN74LS47N IC and 6 5161BS 7-seg for the project. ...
ARDA Adsiz's user avatar
1 vote
2 answers
112 views

Choosing crystal (oscillator) for STM32 project with 100BASE-T Ethernet?

I've googled around and also found ST's AN2867 on oscillator design, but I don't find one key info: How high are the clock precision requirements for an STM32, driving a 100BASE-T ethernet PHY over ...
adrifromhh's user avatar
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41 views

What options are there for multiplying clock pulses by non-harmonic values?

I have a MIDI clock signal which will output pulses at 24ppqn and a device I would like to synchronise which runs at 64ppqn. This is equivalent to a an ⁸⁄₃ clock multiplication. My current method is ...
Pernel_Sned's user avatar
1 vote
1 answer
130 views

24MHz Clock Signal Distortion

I am measuring a 3.3 V 24.576 MHz clock signal coming from a CDCE913. The signal is used to drive 25 audio TDM receivers. The line is terminated in series with a 33 ohm resistor at the transmitter end ...
Semmelrinde's user avatar
1 vote
1 answer
90 views

Driving 5 and 3.3 V square wave from a single terminal

I'm quite new to the topic and for fun I'm building a low frequency square wave generator with parts I currently have. Overall it works just fine while built on a breadboard, however I would like to ...
Maxim Pavlov's user avatar
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1 answer
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Is there an RTC with alarms I can use without an Arduino/microcontroller?

I have a simple project planned for which the electronics component boils down to a clock unit triggering a 555 timer twice a day. The DS3231 seems perfect for this but seemingly requires including a ...
Faceplanted's user avatar
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1 answer
119 views

Xilinx Virtex-7 VC709 FPGA Clock Setup Problem

I am getting started with the Virtex VC709 FPGA board, moving on from a much simpler Digilent FPGA development board. I get critical warnings trying to configure a single ended 100MHz clock from the ...
David777's user avatar
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1 answer
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Is there any way to get a smaller SPI clock speed specifically to only one SPI slave?

I have 3 modules connected by SPI through an ATMEGA328P MCU as shown in the circuit and I have some doubts over the clock speed of the bus. I have a 8Mhz clock on the MCU which I am assuming sets the ...
zoghii's user avatar
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1 vote
6 answers
187 views

Detect presence of 12MHz squarewave without oscilloscope

I have programmed my ESP32 to (supposedly) output a 12 MHz clock signal, to use as a substitute for a broken clock crystal on another microcontroller. The code I used is adapted from this esp32 forums ...
dragoncoder047's user avatar
1 vote
1 answer
108 views

Replacing clock crystal with signal generator [closed]

I have this blob chip module that I'm reverse-engineering, that ran off a 12 MHz crystal. In getting the module out I broke the crystal. It was a two pin through hole component. Big orange blob marked ...
dragoncoder047's user avatar
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0 answers
112 views

Generating an 80 MHz clock from a 100 MHz clock with VHDL in Spartan-7

I am new to VHDL and am targeting a Spartan-7 FPGA, using VHDL. For technical reasons I have to develop outside the Vivado or other environments. It seems like there are several posts that have ...
villaa's user avatar
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1 answer
103 views

What would cause a router CPU to run 44x slower? [closed]

I have a TP-Link Archer C9 V5 router. After a recent power outage it did not come back up, so I am now trying to see if I can fix it. Occasionally it will still manage to boot and work normally, I was ...
sasodoma's user avatar
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2 answers
87 views

Do I need to set configuration bits for oscillator in mikroC in code?

I am new to programming PIC, I use PIC16F684 (via mikroC). I want to do an accurate (up to 1 minute per 24h) timer to control relay, so I chose an external 16 MHz crystal oscillator. I connected it to ...
Ri Di's user avatar
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0 votes
3 answers
137 views

How to connect oscillator to MCU for power saving operation

I have to connect an oscillator (RTV-104EF13P-S-10.000-TR) to an MCU (STM32G051F8P6) in order to have a more precise clock. The datasheet provides very little information about the ...
Harry's user avatar
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1 answer
80 views

Forwarding a clock and display it on oscilloscope

I have been trying to forward 2 clocks, one of them is 12.5MHz, and the other one is 25MHz. when i used an oscilloscope to check the signal, it was not a square wave, and it was like a capacitence ...
Yosh Sinjab 's user avatar
-1 votes
2 answers
125 views

Configuring an astable 555 timer to milliseconds

I am working on a Tinkercad project and I would like a 555 astable clock for it. I am trying to configure the astable 555 timer for every millisecond (or something close). I don't know how to do it, ...
some human's user avatar
0 votes
1 answer
58 views

Inverter Oscillator Ground Return

I have a PCB design for a guitar pedal with a DSP chip processing some audio signals that would normally run off a 32768 Hz crystal, but part of the guitar effect allows the user to change the clock ...
longlivetheDee's user avatar
3 votes
1 answer
363 views

Using a function generator as a clock source to drive several ICs (CD4000 CMOS series & 74 TTL)

I am building a circuit that uses a 4 MHz reference carrier. The used ICs are basically XOR 7486 and NOT 7404, CD4013 flip-flop, etc. I have a function generator which is capable of providing up to 5 ...
Mohamed Abuain's user avatar
0 votes
2 answers
60 views

Clock synchronization in ethernet PHY

I am beginning to start with ethernet PHY. As per my understanding, digital signal will be transmitted and we apply encoding scheme to incorporate clock information into the data signal. Can't we just ...
Isha's user avatar
  • 1
5 votes
2 answers
844 views

What does an AND gate inside a box mean?

I'm looking at this clock diagram, and it has five of these little boxes with symbols that look like AND gates inside them. But, they only have one input. What do they mean here? Source here
ultraturbonoob's user avatar
0 votes
1 answer
47 views

What guarantees are there on when GPIO states are read and written?

I'm fairly new to electronics, coming from software engineering, and it's not clear to me when GPIO states are set or read in microcontrollers relative to a clock pulse. If on cycle n, I toggle a GPIO,...
Julien BERNARD's user avatar
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1 answer
121 views

How do I call a module repeatedly in Verilog, in sync with a clock?

What I intend to do is basically cycle through a LUT created in a second module, by instantiating it in the first. Additionally, I need to call the instantiation in sync with the clock. The basic idea ...
DaveFenner's user avatar
2 votes
0 answers
80 views

STM32f030 Inconsistent clock

I am trying to write my own microsecond delay function for an STM32f030R8t6 by using the counter function on Timer 3. The first time I power the microcontroller up after flashing the delay works ...
Eric14003's user avatar
0 votes
1 answer
56 views

Interrupted SSI clock sequence

I measured the following clock and data sequence (time axis is in microseconds) between a Beckhoff KL5001 encoder module and a 19-bit SSI encoder. Apparently the clock is interrupted 3 times before ...
Christian K.'s user avatar
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0 answers
66 views

How to improve my clock trace?

For my current project, I use two AD9226 clocked by the same clock oscillator (SM77H) at 25 MHz. The image below is a snapshot of my PCB. U1 and U2 are the ADC, and C1 is the clock. I also highlighted ...
Andi Ilmy's user avatar
0 votes
2 answers
92 views

Adding on and off state in a 555 timer clock circuit

I'm making a clock signal for my circuits, and I'm utilizing the 555 timer for this. I made this circuit below which outputs a clock signal. And now I'm trying to figure out how can I add on and off ...
Noobielectrix's user avatar
6 votes
1 answer
824 views

10MHz reference vs 1 PPS vs GPSDO

In the context of Software defined radios (SDRs), what are the differences between using an external 10MHz reference versus using a GPSDO? Why/when would you use one over the other? And how does the ...
BigBrownBear00's user avatar
0 votes
0 answers
64 views

STM32F031 HSI clock temperature impact

I developed an electrical board that contains a STM32F31C4T6. The product worked well for more than two but since this summer I have customer feedback on malfunctions of the card, it no longer works ...
Kolia's user avatar
  • 55
1 vote
5 answers
221 views

Clock Signal over long distance

I'm building microphone array using 16 ICS-52000 MEMS microphones and I propably have problem with clock singal because of the long distance. Below is output signal of the 8 microphone I have already ...
erysvh's user avatar
  • 41
1 vote
2 answers
464 views

What is the fastest achievable output speed for an FPGA?

To sum up the question, I would like to know what is the maximum frequency with which I can toggle an output of an FPGA. I do not intend this question to be specific to any particular board or vendor. ...
tpimh's user avatar
  • 513
0 votes
0 answers
38 views

DC Offset in LCD clock signal

I am getting DC offset in clock signal. Clock signal has 24MHz frequency. The DC offset is around 400mV. Also I was expecting Square shape waveform but I am getting sinusoidal with DC offset. Clock is ...
Harish's user avatar
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1 vote
2 answers
113 views

Underclock the microprocessor [closed]

Suppose datasheet rated clock frequency range is 8MHz to 16MHz. What if we try to operate it at 6MHz. How will it impact the operation?
Praveen Vadagave's user avatar
2 votes
0 answers
85 views

Low jitter clock multiplier

I am using a 2-channel arbitrary waveform generator to generate two 40 MHz signals. The AWG also has a trigger signal output: short (~20 ns) pulses of ~2.5 V. The AWG has a negligible jitter of about ...
Andrew's user avatar
  • 21
3 votes
1 answer
94 views

Pulldown resistor on CLK input of 74HC109

I'm having trouble understanding the purpose of R3 on the CLK input of the 74109 in this circuit: This is the Clap activated light circuit by Frank Donald. As far as I know, the 741 should be able to ...
Fabrizzio Reumann's user avatar
0 votes
2 answers
176 views

What is the best way to use 0 ohm resistors for a large number of signals?

I'm fairly new to PCB design, so maybe I start with a basic 0 ohm resistor like this: I have both output pins (SLEEP & RESET) on the DAC chip. I want to have two options on my PCB, one with 3-pin ...
johnny_1010's user avatar
0 votes
0 answers
140 views

How fast can a Schmitt trigger operate? Can I use it for signal conditioning digital serial data?

I would like to know if I could use a Schmitt trigger chip (e.g., 74HCT14, CD40106B and 74AC14) to clean a 12MHz serial digital signal that has gone through a long cable and will pass through multiple ...
Emerson's user avatar
  • 423
0 votes
1 answer
117 views

STM32G431 CMSIS clock setup failed

I am currently developing with the WeAct Studio STM32G431 Board, but when I tried to configure the clock setup something went terribly wrong. During the debugging process the ST link connection broke ...
Jakob Flocke's user avatar
0 votes
1 answer
83 views

Slave SPI not firing interrupt

I have 2 STM32F407 discovery boards for which I'm trying to setup a multi slave SPI bus. The first slave is working but the other one is making problems once I connect the second CLK input onto the ...
Michael's user avatar
  • 113
4 votes
2 answers
510 views

Why I am getting one clock cycle delay in Verilog case statement?

I have a Verilog code here: ...
Seforo's user avatar
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