Questions tagged [timer]

Circuit to generate a signal a specific time after a trigger event. The timing can be defined by an RC time constant, or by clock pulses from an oscillator.

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36 views

300ns Pulse Generator to Drive LED

I wanted to use a 555 timer in astable mode to generate a 5V signal to flash an LED on and off. This works fine when the pulse length of the LED is in seconds or milliseconds. But this got me thinking ...
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18 views

What Happens when PWM Period register and Compare register is also loaded with same value

Consider, PWM engine based on timers, PWM period register is loaded with 0x3FF (10bit, specifies the period of pwm frequency) and compare register( to vary the duty cycle , when timer count = cmp ...
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2answers
70 views

How can I hold Vcc logically for a while?

I want to hold Vcc at 5 volts for approximately 35 seconds. I can set this with a capacitor and r-c circuit. Assume I'm not take too much current from the capacitor, about 5 uA. But, during 35 seconds ...
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48 views

Is there an easy way to oversample encoder input in STM32 microcontrollers?

I need to oversample the encoder input. Currently the single channel resolution is 2500 pulse/rev, thus combined channel resolution is 5000 pulse/rev. I need more or less 10 times higher resolution. I'...
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55 views

How to develop a compact multi function timer like 35238-MP?

There are many timer circuits available in the internet using IC555 or IC 4060 also using microcontrollers like arduino, or even using only mosfet. I also already made a simple timer using IC555. ...
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49 views

In search of revision to 555 Monostable circuit to create a resettable timer

First of all I am getting back into electronics after a LONG pause and am going back to the 555 roots. I am attempting to create a simple circuit that will light an LED after a period of time. In ...
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27 views

How to use TA1 of P1.6 without also using it on P1.2 on MSP430F1101

I have been struggling for a lot of time now, training to use the pwm function on pin 1.6 of the microcontroller. For P1SEL=BIT2, it is correctly using TA1 on P1.2, but for P1SEL=BIT6 it is not using ...
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71 views

OUTPUT pin is not going LOW in 555 timer IC

I was working on a simple monostable IC project and I came acroos this problem. When the switch is closed which triggers the pin 2 and sets pin 2 on low logic OUTPUT goes HIGH. As per my settings of C ...
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2answers
76 views

How to exit from an interrupt's loop for MSP430

I'm new to MSP430 and microcontrollers. Right now I'm learning interrupt routines and trying to write a program that changes the LED's state (OFF-ON-BLINK) by every press on P1.1 button. I have used ...
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23 views

STM8s Timer1 repetition counter (RCR) not working

I'm trying to set up PWM on Timer1 Channel 1(N) on the STM8S105K6 together with a repetition counter. Here is my simple intitialisation function for TIM1 which I used to test PWM: ...
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30 views

STM32 - several PWM signals with different multiplied frequencies

Is it possible using STM32 F to generate several PWM signals with one timer, but each channel has different frequency (multiplied of two) of PWM? All signals must be synchronized, so I need to use ...
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44 views

Timer switch suggestions?

I have a simple security/alarm system I built for my carport after a thief took advantage of me. It simply has a strobe light and an extremely loud siren, using photoelectric sensors. When the sensors ...
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21 views

How to setup STM32F103C8 encoder triggered output signal

I have a project where I need to read the encoder phase A&B to output the pulse so I can drive a motor, I did some research and saw this picture where it is exactly what I wanted to do: output a ...
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78 views

How does the 555-timer AM radio work?

The 555-timer is used here as a demodulator. I don't understand how the 555-timer generates the desired signal. Shouldn't the output have the same frequency as the carrier signal? Can someone please ...
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1answer
27 views

2 on delay 555 timers in the same circuit

Hello: I am trying to design a circuit in which one LED (D1) turns on after a certain amount of time has passed and then a second LED (D2) turns on after a different amount of time has passed. This is ...
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3answers
200 views

How are system clock and oscillator frequency related?

My question is given a, for example, a quartz oscillator on a MCU board, how is the system clock generated? I'll break down this question into several parts below: I always have the impression that ...
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2answers
40 views

modulate a 555 pwm circuit based on an input voltage

I am trying to vary the duty cycle of a pwm signal based on an input voltage (higher voltage = higher duty cycle). I currently have a functional astable set at my desired freq (50Hz) and it is fed ...
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57 views

74HC5555 triggering

I want to use the 74HC5555 as a long period oscillator for which it seem suited. and I wish to use the internal oscillator (and divider) to determine the Q / not Q transition time of 28 days The ...
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2answers
77 views

STM32 Timer Settings Changing

I'm using STM32F407VG. I created a 28 khz square wave by using Timer PWM Generation. When i look at the oscilloscope, i can see it clearly. I'm having a trouble to change frequency of PWM without ...
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22 views

Issue using TCC3 of microchip SAMD21J in variant file

I am writing variant files for SAMD21J/G/E. I am unable to use TCC3 of SAMD21J/G/E in Variant.cpp for arduino IDE. If it is used Arduino IDE shows error TCC3 undeclared variable whereas, all other ...
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1answer
62 views

STM32 calculating/getting timer tick

I am writing code for an STM32L433RC MCU that returns the tick period of a timer (TIM1, TIM2, TIM6, etc.) using the LL driver but I can't figure out how to calculate the timer clock frequency ...
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2answers
63 views

NPN transistor switch with load at emitter pin

I found a schematic with a 55 timer driving two transistors, each of which switches an LED (see below). When the 555 output is low, LED1 is OFF and LED2 is ON. When the 555 output is high, LED1 is ON ...
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3answers
74 views

Usage of 555/556 Timer as a One shot timer

Im using two 555 timers / one 556 timer IC for a project. I've used it a couple of times before but never in monostable mode. Basically I need to activate a DC Motor in one direction for a set amount ...
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39 views

STM32 using trigger to start timer

i want to use a Timer which generates a 40kHz frequency to toggle an output, when a start trigger arrived on an input. After a high signal was detectet on that input, the GPIO should be toggled 20 ...
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34 views

STM32 in emmc-slave role. DMA transfer by both edges of external clock

I want to implement emmc protocol in a device role with STM32 (for now I've had ST-Nucleo-F767ZI and ST-Nucleo-F429ZI dev boards). Idea is to have a bridge to real emmc with STM32 as an adapter. STM32 ...
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149 views

Why does the 555 timer have a maximum frequency of 2MHz?

according to the website, the 555 timer has a maximum frequency of 2MHz. Why is it not less or more? What property of the timer makes the limit of the frequency? Website:http://groups.ist.utl.pt/lee/...
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1answer
61 views

555 Timer works perfectly until solenoid connected to relay then continuously triggers

Note: the solenoid text in the image is just a representation. Real world everything is fine until I connect the solenoid to the Com and N/O of the relay. It then cycles once and starts to ...
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3answers
65 views

DC/DC step down timer

I need simple circuit that can provide step down of voltage after some time. For example after connecting 24V, on output there will be 24V for 500msec, after that voltage will step down to 8V and stay ...
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3answers
175 views

Monostable circuit with 1 hour high output

I want to build a monostable circuit (a circuit with one input as a pushbutton), that will output logic '1' when the pushbutton is pressed for one hour (with the least error possible) then go back to ...
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240 views

STM32 - Using Timer as timebase source for HAL in FreeRTOS application

I am learning more about freertos by making a task based program. My problem comes when initializing and configuring the HAL time sources. I read that it is necessary to choose another HW timer as ...
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2answers
76 views

simple cheap delay start relay?

What is the cheapest, simplest component or device that once receives power will wait approx. 1 second before outputting that power, like a delay relay. It can be any small DC voltage as it will power ...
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3answers
127 views

which capacitor and resistance values ​can I get a 2.1Mhz signal from the tlc555 timer IC?

With which capacitor and resistance values ​​can I get a 2.1Mhz signal from the tlc555 timer IC? I tried the astable circuit diagram, but I got an error. Which capacitor and resistance values ​​should ...
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1answer
66 views

Push button with auto off

How to make push button switch with auto off after about 5 seconds. Output circuit is high (active) for max 5 seconds when I keep pressing push button. Output will be low after this time or when I ...
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1answer
100 views

What space applications use the 555 timer? [closed]

The 555 timer is considered the most famous integrated circuit of all time and is also credited with a versatile use in space travel. Hans R. Camenzind (the designer of the 555 timer) said that this ...
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38 views

problem with using DAC with DMA and timer trigger

I'm trying to configure a DAC with DMA and timer trigger to make a sine wave with 1KHz frequency(100 samples) and I'm using registers. my problem is that the DAC is not triggered when the timer value ...
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3answers
83 views

Simpler delay before power on

I'm trying to create a circuit that will make the output go high some amount of time after a 5V control signal goes high. That delay time may vary by application, so I'll use a potentiometer in place ...
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32 views

ATMega32u4 Timer code not working

The following timer code running on a 8Mhz ATMega32u4 should toggle the onboard LED every second, and calling the ISR code manually does so. Yet, the ISR does not seem to get called. Could anyone ...
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7answers
4k views

How do I make a nanoseconds counter?

I want to make a counter that can count the time between pulses in nanoseconds. The counter starts to count when a pulse enters a pin (at the start of the pulse) then stops when a second pulse comes. ...
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91 views

STM32 Timer, variable frequency output

preface in the AVRs, when I wanted to create a variable frequency waveform (50% duty cycle) within a limited range defined by timer frequency and its prescaler, I used CTC mode: the OCR registers ...
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1answer
36 views

How can I make cyclic 4 min. delay circuit that works on 5VDC

I have a automatic liquid drip project, which works based on timing. Basically there are three manual switches and each switches will select different delays such as 2 min., 3 min. and 4 min. When ...
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1answer
37 views

How can I time-switch a few loads very precisely?

Let's say there are 5 different loads, and I need a circuit to switch them on/off based on a pre-tunable delay. (E.g. first one immediately, second one exactly 2.78 seconds after the first one, third ...
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1answer
83 views

STM32 - How to trigger a DMA transfer via hardware timer, while CPU is in SLEEP mode?

I'm trying to set up a simple project that does the following: Enter sleep mode and in the main loop, it waits for interrupt - __WFI(). Transmits data from a buffer[4] to the PC, via UART. The ...
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1answer
98 views

Data flip flop - I don't understand its purpose

The data flip flop can delay operation based on the time of the cycle of the clock. If the clock's cycle is fast, the DFF is useless because it's like an instant change. Is it possible to change the ...
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4answers
48 views

What device can I use to parallel 4 dry contact signals from 4 timer relays

What device can I use to multiplex 4 dry contact signals from 4 timer relays to actuate an isolation valve? In other words, any of the signals from the timer relay should be able to actuate the ...
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1answer
43 views

Using input capture when the PWM duty cycle is 100%

Suppose I have a PWM signal whose duty cycle varies between 0% (logical LOW voltage all the time), 50% all the way upto 100% (logical HIGH voltage all the time.) In case of 50% it easy to measure with ...
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50 views

Stepper Motor sometimes working fine and other times not

I am experimenting with operating a Stepper Motor that is connected to a Magnetic Encoder. The Stepper Motor is also connected to a Motor Driver, which will be controlled by an STM32F4 microcontroller....
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30 views

Wiring DH48-S timer to be self-latching

I am trying to wire a DH48-S timer to operate a three phase pump. I have a remote controller/relay for the pump which is located about 1 km from my house. The remote controller can be configured to ...
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36 views

on delay and off delay in one circuit

How to build a 555-circuit IC with a delay at the beginning and a delay at the end? I want to make a LDR switch that When it gets dark Turn on the relay after 10 sec and When there is light Turn off ...
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1answer
37 views

PWM edges issue on a STM32F0 micro

I have a STM32F051R8 (STM32F0 discovery board) I am trying to use to generate a PWM using a timer and change the pulse width at runtime. My code is: ...
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97 views

STM32H7 PWM with DMA not working properly

I'm using the PWM mode within the TIM15_CH1 hardware to create a varying pulse width modulation to run the ws2812B (LED Light strip). Current setup right now is that I have a buffer of pre-calcuated ...

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