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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3answers
68 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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0answers
27 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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0answers
41 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
34 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
35 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
49 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
89 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
45 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
33 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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0answers
44 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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0answers
28 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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0answers
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
35 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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0answers
31 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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1answer
50 views

How to make a 500-1000ms timer circuit [closed]

There are countless applications for delays of a few hundred milliseconds up to a few seconds. I have not been able to find some elegant solution, but I am sure that there must be a way, and that some ...
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1answer
40 views

stm32f103: a timer triggering DMA to update another timer's CCR using libopencm3

I'm playing with the blue pill. Here I run TIM2 and enable the DMA on its update event, according to Table 78 of RM0008, the DMA channel I should use is channel 2 on DMA1. Then I want the DMA to ...
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1answer
30 views

Timers prescale and postscale

So i understand that a prescaler divides a clock, and PR2 is the period register which when the timer TMR2 reaches the value it increments from 0. Why is a post scaler needed to divide a non-clock ...
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1answer
39 views

Countdown to ON timer

I am looking for a COTS countdown timer - preferably with programmable or preset, short countdown times - that will turn 110v OFF when timer is initiated, and back ON when the countdown ends. I know I ...
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1answer
35 views

Error Real Time Clock implementation AVR microcontroller

I want to create a real-time clock using ATmega328p microcontroller. The microcontroller's frequency is 1 MHz. So, I think I should use timer interrupts in CTC mode to generate interrupt every second. ...
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2answers
51 views

problem facing in running the three function in arduino

I am making and Arduino program for a 3 phase inverter. I have designed 3 functions for each individual phase. In 3 phase, the 2nd phase has to start at 120 degree with respect to first phase and ...
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0answers
36 views

How to replace AVR _delay_ms() with timer

Good day. I need problem with replacing _delay_ms() bultin function with timer. MCU: Atmega644@16Mhz My code (simplified): ...
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0answers
48 views

STM32L4 LPTIM as pulse counter of intermittent pulses fails when initializing with no pulse

I'm working with LPTIM as a Pulse Counter on a STM32L432KC, I have a rain gauge connected to LPTIM1 (PB5) and a anemometer to LPTIM2 (PB1). Both configured on STM32CubeMX as Standalone: counts ...
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0answers
99 views

STM32 Timer - Issues with generating 1 us pulse on GPIO

I am using Nucleo-F767ZI board which has STM32F767ZI controller on it, and am in need of sending out a particular structure of elements bit-by-bit through a GPIO pin once every microsecond (1 MHz freq....
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4answers
102 views

Crystal tolerances and what that means for timer interrupts

I'm developing a system that needs to periodically wake up and perform a process. We're currently targeting for an hourly wake up (give or take, this spec is very loose). The key here is the unit cost ...
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2answers
53 views

Redundant capacitor?

I have the following circuit It's a basic traffic light circuit using a 555 timer and decade counter. All works fine but what is the purpose of the 0.1 microfarad capacitor on the left of the diagram?...
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1answer
77 views

How to use PIC16F84A TMR0 Interrupt as a substitute to the Sleep instruction in Assembly

I have this circuit: So my problem is that I'm having trouble using the TMR0 interrupt as a delay or substitute to the SLEEP instruction in the PIC16F84A. I can't quite get the concept of using the ...
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1answer
56 views

Creating an electric alarm

I usually forget to turn off the geyser. To solve this problem, I want to create an alarm that will go off, 10 minutes after I have turned on the switch for the geyser. I'm a computer science student. ...
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1answer
31 views

Timer (output compare mode) not working on stm32f411re

I am using an stm32f411re nucleo board. I am trying to configure the Tim2_ch1 module in output compare mode. I have written the code by referring to the reference manual: https://www.st.com/resource/...
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0answers
13 views

Cannot seem to initiate Inerrupt in STM8S TIM2

I trying to initiate an interrupt every 1 minute. The Timer itself is working however, the interrupt does not seem to work. I have added my main code + the vector interrupt code. Please let me know ...
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1answer
54 views

Identifying a vintage lighting sequencer method

In India, on certain social festivals like Durga Puja, Kali puja etc, lighting decorations are done around roads etc, where various themes or stories are animated (such as stories from Aesop's fables),...
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1answer
63 views

Converting pulses to RPM

I have a question about how to take an output from a sensor and calculate RPM. The sensor produces a square wave at a maximum frequency of 1kHz. So I think I have two options: Count rising edges in a ...
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2answers
57 views

Driving a seven-segment LED display without interruption

Microcontroller drives 3 digits seven segment type LEDs sequentially. ...
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1answer
74 views

555 timer circuit causes spikes on power supply line - how to decouple?

I'm using a 555 timer circuit similar to this one to blink a couple of LEDs at around 1 to 30 Hz: The oscillations are causing huge spikes on the 5V supply line. There is an audio circuit running off ...
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1answer
185 views

555 startup timing issue

I'm new here, as I'm slowly drifting from mechanics and programming into more electronics stuff. The question I have, is if anyone could possibly point me in the right direction, as all of my searches ...
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1answer
73 views

“Voltage divider holds 37% of supply voltage at negative” wrong in textbook

In my textbook, it states that "the voltage divider of R3:R4 holds 37% of the supply voltage at negative". However, I think it should be 63%.
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2answers
50 views

How to adjust the brightness of a small LCD(21V) with a potentiometer?

I want to adjust the brightness of a small LCD with a potentiometer. How can I use a 555 timer to make a PWM which can give out an output of 21V from a 5V input?
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1answer
48 views

programmable timer / clock generator

I need to generate a square wave / clock with configurable frequency between say 60 to 500Hz. There are not stringent requirements on the frequency stability. I need to be able to modulate this ...
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1answer
111 views

Configuring LPTIM Parameters with the STM32L4

I bought an STM32L433 Nucleo-64 board (STM32L433RCTxP) and I am trying to learn more about the LPTIM peripheral. I am experimenting with setting up the LPTIM1 peripheral so that it generates an ...
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0answers
52 views

Create a circuit that saves battery

I am trying to make a timer for myself. I select how long the timer runs for via a switch. The timer should begin counting down via a tilt sensor (or just a momentary button/switch to start) and count ...
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2answers
65 views

How to store the last counting value in EEPROM in ATmega8 after power failure

I written a program to store the last counting value according to ATmega8 datasheet. but it didn't save the last value. The counter variable went to zero after power failure. Please check the ...
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0answers
63 views

millis() function for PSoC4

I'm replicating the function of millis() for the PSoC4 in order to store the timestamp of a signal's maximum amplitude. For this, I'm using a timer with a 1kHz to ...
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1answer
92 views

Reset and trigger 555 timer with one push button

I want to turn on a LED with a single push button. When the button is pressed, the LED has to be turned on for an X amount of time. But what I also want, is to turn of the LED with the same push ...
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1answer
58 views

RC timing circuit application

I have a timing circuit application that depends on the intervals with duration determined by an RC circuit. When a capacitor is [dis]charged through such a circuit, a voltage level across the ...
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1answer
89 views

MSP430 Timer Interrupt Not Triggering

I'll post my code below. The problem is that the MSP's ISR_TRAP function (a function that handles ISRs that are not otherwise handled) is triggering and trapping me in its endless loop. This happens ...
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1answer
97 views

Can someone explain this part of circuit from BQ500212A?

As the title says, I am struggling to understand what this part of a circuit does. It's part of this evaluation module. Is there any chance the BSS138 transistors will activate without the SNOOZE/...
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1answer
67 views

Difference between Shadow register, match register and capture compare register in a timer module

On page 704 of the data sheet of the Texas instrument Tiva C TM4C123GH6PM....it has these three registers in its timer module.i searched about these registers and found that shadow register is a ...
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1answer
122 views

dsPIC33 oscillator and timer configuration

I configured my dsPIC33 oscilator to operate at 60MHz using a 15MHz external crystal. So, to confirm the configuration, I did a routine to oscilate a pin, high and low, with a 2us period. But it seems ...
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0answers
45 views

ADC Overrun with Multimode, Scan and timer-triggered configuration

I'm using the STM32F446VE with 3 ADCs. I have a 50 kHz PWM running and want 2 of the ADCs to measure 2 Channels synchronized with the 50 kHz PWM. To achive this I used the regular simultanuous dual ...
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2answers
51 views

Can I use a 12V DC supply on this digital timer switch?

I recently purchased a digital timer switch which I assumed would work at 12V DC for powering a simple circuit which takes a 12V DC supply, and has maximum power consumption of 8 watts. So the maximum ...

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