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0
votes
1answer
158 views

Does this clipped-sine oscillator need a buffer?

I'm considering using an Abracon VCTCXO, the ASVTX-11-121-19.200MHz-T to run an AT89LP428. I'm trying to make sure that they're interoperable, but the Abracon device doesn't say anything about the ...
0
votes
2answers
62 views

Can I use MCU's internal oscillator when communicating with GPS and cellular modules?

Can I use MCU's internal oscillator when communicating with GPS and cellular modules? I want to avoid connecting external crystals for the MCU since they generate noise, extra components, extra costs, ...
2
votes
1answer
246 views

Separate GND-plane for microcontroller crystal resonator

1.  Background info I'm designing a board for an STM32F767ZI microcontroller. This microcontroller has a primary oscillator for the SYSCLK (overall system ...
0
votes
2answers
177 views

How to limit the output voltage of a TCXO?

I am using an SiT1552 MEMS TCXO providing 32.768 kHz. It will be sourcing two ICs: a microcontroller and a DA14580 Bluetooth Low Energy transceiver. The ICs and TCXO are all powered by 3.3V. The TCXO ...
0
votes
1answer
185 views

Crystal reference and capacitors for w5500

I'm selecting the caps for the crystal oscillator of the wiznet W5500. The standard Load Capacitance for 25Mhz crystals is 18pF. I found out that the hardware guideline claims for a Load Capacitance ...
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 ...
0
votes
1answer
200 views

How to connect a 4-pin OSC (crystal oscillator) to an IMU (BNO055) with only 2 pins dedicated to an external clock?

I am using the BNO055 : https://cdn-shop.adafruit.com/datasheets/BST_BNO055_DS000_12.pdf and I can't seem to figure out how to connect a standard external oscillator clock to the chip. As suggested, ...
12
votes
3answers
3k views

How do processors control their clock speed?

I recently came across an STM processor with 2 oscillators on the circuit - I suppose one for high-speed operation and the other for low power. For something like a desktop processor where the clock ...
2
votes
2answers
341 views

Crystal oscillator on custom ATMega2560 board is at the wrong frequency

I have designed a custom board using an ATMega2560. The board works fine when configured to use the internal oscillator. The board stops working when I configure it to use the the external 16MHz ...
-1
votes
1answer
98 views

How to match two clock signal's phases which are physically apart in two locations?

Suppose, I have one Tx and one Rx physically separated by the long distance with clock signals CLK1 and CLK2 as shown in fig. (say both of 50MHz). I wish to align them in phases. By that I mean, ...
0
votes
1answer
398 views

Is it possible to build an oscillator from an NPN transistor?

I have an old Russian clock, that you wind up every day, but has a AA battery for the alarm. It somehow creates sound and vibration by resonating a metal piece. However, recently this broke. And my ...
0
votes
1answer
124 views

How can I determine the capacitance required for an oscillator (NOT A CRYSTAL!)?

In a typical clocking circuit configuration, where a crystal is tied at the input to an amplifier such as is shown below: The capacitance required for \$C_1\$ and \$C_2\$ would be based on the load ...
0
votes
3answers
127 views

Interferometry's arch nemesis: CLOCKS

I have a problem and it spans easily 4 Stack Exchange forums so let's wrap up quick here. I'm doing radio astronomy. I'm setting up interferometry among 3 radio telescopes. (I'm using three PCB's with ...
2
votes
4answers
392 views

Drive XTAL input with logic signal

I'd like to drive the XTAL input to a chip with a logic signal (3V3, 32kHz square) instead of using a real crystal. In general, is this okay, or does the signal need to be filtered/attenuated? At the ...
1
vote
3answers
2k views

RC circuit as clock source

I am not understanding something very fundamental here , I have read that an RC circuit can be used as a clock source. From this I assume a DC input. Playing around with my oscilloscope the only time ...
-1
votes
3answers
252 views

Precise Clock Signal

I'm working on a project where i try to make a normal clock.Everything is finished and ready except for the main signal coming from the oscillator. I'm making a relaxation oscillator of course but i'v ...
2
votes
1answer
322 views

Do I need buffer inverter for a Crystal Oscillator?

I want to be able to select between two clock signals, 16MHz and 1MHz, using an analog SPDT switch. Do I proceed correctly, by buffering these oscillators? Or is there a better way to do this? The ...
0
votes
1answer
62 views

K50-HC0CSE25.0000MR Clock signal not being driven to correct logic levels

I am using a K50-HC0CSE25.0000MR to generate a 25MHz clock for the DDS IC AD9833. I have hooked up the clock output directly to the MCLK input of AD9833 as shown in the diagram.. The data sheet ...
1
vote
0answers
145 views

Can't get PIC16F1764 to run at 32 MHz INTOSC

I have a problem with a PIC microcontroller. I can't get it to run at 32 MHz. Via page 78 of it's datasheet (document number DS40001775B). The steps for selecting 32 MHz FOSC operation are clearly ...
2
votes
3answers
2k views

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 + ...
2
votes
1answer
329 views

PIC18F67J90 Clock Selection [closed]

I have two options to select system clock: INTOSC FOSC I want to use the internal clock at 8/16 Mhz. Which one should I select and what is the difference between FOSC and INTOSC?
4
votes
2answers
651 views

What kind of external clock is needed for PIC32?

Nearly all PIC32 errata I have read (Item 41 - page 5) have the same issue - A crystal oscillator cannot be used as an input to the Primary Oscillator (OSC1/OSC2 pins). An internal oscillator ...
2
votes
1answer
563 views

PIC32MX can't get 80 MHz Clock from Internal RC OSC

I am using PIC32MX795F512L with the internal RC oscillator. By changing the settings of the config, I can get to 60 MHz max. But I can't get to 80 MHz. When I change the config for 80&#...
1
vote
1answer
1k views

Need Help In Creating and Debugging a 8Mhz CLK Circuit

I want to create a CLK generator circuit that will work at 8Mhz. I'm following this design (from http://www.electronics-tutorials.ws/oscillator/crystal.html): My crystal is 8Mhz HC49/US, with 20pF ...
0
votes
2answers
233 views

10 USB Hub ICs from 1 Crystal Oscillator?

I am designing a PCB with 10 individual USB hub ICs onboard. They all require a clock input and I am wondering if it is possible to drive all the clocks from a single crystal oscillator? The hub IC ...
3
votes
1answer
744 views

How does a CPU change frequency? [duplicate]

From what I've found on the internet, CPU clocks work with piezoelectric material to produce a very stable oscillating signal but those materials must change in shape or size to get a different ...
-2
votes
1answer
80 views

A resistor circuit that resitance of resistor is controlled by single-frequency oscillator [closed]

This is actually more of a fun idea, but: is there any resistor circuit such that resistor's resistance value is controlled by a single-frequency oscillator? So resistor's resitance varies by the ...
3
votes
0answers
139 views

Can Two Or More ATTinys Share One External Crystal? [duplicate]

I've got two I2C Slave ATTiny85 chips both running at 16MHz with external crystals. Can they both share a single crystal with the 22pf caps? Is there anything wrong with this? I don't have any free ...
1
vote
3answers
2k views

Numerically Controlled Oscillator (NCO) Sample quantity

Ive been doing some research on NCOs and some initial information (or lack of information) is bugging me. Ive read a few articles on this topic: FPGA based NCO Blog on NCOs But i still don't ...
1
vote
1answer
982 views

ATmega162 fuses to select external clock 12Mhz?

Could anyone tell me how I could change the fuse bit, so that my ATmega162 uses 12 MHz external crystal. Once, I made the changes in the AVR fuses wrong the AVR went dead. That is why I need ...
0
votes
3answers
366 views

Simple switching between clocks using oscillator disable pins

I am working on a circuit where I need to use different clock sources. I am using two HCMOS oscillators. Both oscillators have an disable pin. When disabled, the clock output buffer is placed in tri-...
1
vote
1answer
580 views

Proper oscillator for CPLD

I plan to use KC5032A40 as a clock source for CoolRunnerXPLA3 256. I power it with 3.3V and interface it as suggested: I perform the measurement at the Test Point and do not add any CL capacitance, ...
0
votes
2answers
608 views

Crystal Oscillator design with no data sheet

I am a newbie to circuit design and I need a 50MHz clock. I went to a local electronics store and got a 2-pin radial Quartz crystal. I do not have a data sheet for this. The only markings for the part ...
-1
votes
2answers
159 views

Analyzing clock oscillator using timing diagram

In a recent examination a friend of mine was asked to analyze and find the frequency of oscillation of a clock oscillator using timing diagram as shown below: Can someone give me directions as how to ...
4
votes
2answers
3k views

What components are needed for a 20MHz square wave clock?

I would like to create a 20Mhz clock that generates a square wave for the home-brew Z80 computer I' making. I already have several 20MHz crystal oscillators but am at a loss when it comes to circuit ...
1
vote
1answer
683 views

Crystals as RLC circuit? How?

What gives the crystal oscillator a property of Inductor? How does energy transformation between electrical field and mechanical stress and strain makes oscillator work like a Inductor? I know how ...
0
votes
1answer
164 views

Crystal and Oscillator [duplicate]

I know that crystal oscillator is a type of oscillator. But why in colloquial terms crystal is different from oscillator and how they are physically different?
2
votes
1answer
2k views

What is the PPM of the clock oscillator in a smartphone?

Is there a way to know the ppm of the clock oscillator in a smartphone? For example, in the Android documentation on System Clock, there is a function elapsedRealtimeNanos, which guarantees a ...
3
votes
1answer
1k views

Clock generator with two inverters - how does it work?

I recently assembled a little electronics toy that flashes 10 LEDs one after the other. Unfortunately I do not understand why this circuit is able to provide a clock signal- it looks to me like the ...
1
vote
0answers
1k views

stm32f2xx HSI configuration does not work correctly

I'm using below settings (in SystemInit function) to configure a STM32F215RG MCU to work at maximum speed (120MHZ) with USB support: ...
1
vote
1answer
358 views

DS1077 to drive a PIC's clock

I found the DS1077, a "dual-output, programmable, fixed-frequency oscillator". I was wondering if it would be possible to let this chip provide the clock signal for the PIC(18F46K22) that operates the ...
7
votes
5answers
4k views

Why aren't 1Hz crystals used to measure seconds?

According to Wikipedia: Many clocks use a 32.768KHz crystal. Is this because the crystal is smaller than a 1Hz crystal? If 1.0 Hz == 1.0 second. Then, why the need for the division?
3
votes
4answers
637 views

What kind of oscillator should I use for a binary clock?

I've seen that a lot of clocks use a 32.768KHz crystal. I'm curious why that is exactly. I am working on a binary clock project with some 4520 ICs. I have some 555 timers too, but I want to use a ...
3
votes
1answer
488 views

Can I dynamically change the input clock frequency of the AT91SAM3X8E?

Background: I'm attempting to use an AT91SAM3X8E microcontroller (for Arduino Due compatibility) to create a USB to \$I^{2}S\$ interface. Most \$I^{2}S\$ CODECs require a master clock that is \$MCLK=...
3
votes
1answer
350 views

Possible to tap a PLL signal as a clock for multiple devices

We have an oscillator providing a clock signal for an MCU. It has oscillator in and out pins: XTAL-IN and XTAL-OUT. We'd like to use the same clock signal as a digital clock input to another MCU. ...
0
votes
2answers
1k views

Standalone MLCK generation for I2S

I'm looking at switching a rough hardware design from using a master-IC generated MCLK signal for I2S to using a standalone MCLK generator circuit. I'm a bit new to this area of electronics, but from ...
10
votes
2answers
4k views

Sharing an oscillator between two ICs

I have a microcontroller and an FPGA on the same board. If they're both going to run at the same clock speed, can I just use one oscillator to clock them both? There seems like there is something I ...
17
votes
6answers
29k views

Using the ATMega328 with the internal oscillator?

I have a project that I think would be best suited for an ATMega328P. However, in every simple project I've seen, people always hook up a 16MHz external oscillator. From what I can see, it should have ...
5
votes
2answers
807 views

Clock Shape Changes with Two O-Scope Probes

I have a Max V CPLD development board which has a 10MHz oscillator onboard. I hooked up CH2 probe to the output pin and then wrote a small VHDL program that output the clock to an external pin. I ...