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.
2
votes
1answer
71 views
16-bit timer of ATMega: How to calculate timer count?
I try to use the 16-bit timer of ATMega on each midi clock tick. A beat has 24 midi clock ticks. So e.g. 60 beats per minute = 1 beat per second = 24 ticks per second.
How can I set the timer for x ...
6
votes
1answer
151 views
Simon Says without Microcontroller
I'd like to create the classic game of Simon Says utilising nothing but logic circuits, LEDs and ICs, no Microcontrollers like the Arduino.
I would like to use 4 LEDs and 4 Tactile Switches for this ...
1
vote
3answers
112 views
Delay function in ARM programming
I have just started programming on ARM, I had some experience on AVR but not that much. The question is probably too trivial but the material about ARM is too little on the net... sorry anyways.
I ...
3
votes
2answers
104 views
Time Delay Relay: output = HIGH until triggered, then return HIGH after interval?
My goal is for a button press to temporarily disrupt the input voltage (120VAC) for a specified interval (around 10 seconds). Ideally, I'd like the interruption of voltage to coincide with the ...
7
votes
1answer
61 views
Missing Q11 output on 4060
Is there any reason why Q11 is left out on 4060 IC? I've read it was done to extend the max pulse time (highest clock divider) but why was it done on Q11? Why not Q12 and therefore have a full 8-bit ...
-2
votes
1answer
83 views
Circuit doesn't behave as it should [closed]
I have the following schematic:
The original one (the second one) may be found here: http://www.zen22142.zen.co.uk/ronj/24h.html. Note that the chip shown is a 4060 14-bit binary counter.
The ...
0
votes
0answers
33 views
Pulse extender device [duplicate]
What should I use to extend a 1/2 second GPI pulse that generates out of a cue trigger port twice an hour by a schedule from a Cisco D9850 receiver, to 5 seconds duration or more?
4
votes
2answers
186 views
Problem with 555 timer and 4017 counter
simulate this circuit – Schematic created using CircuitLab
I'm attempting to make a circuit that flashes each LED sequentially. So far my 555 timer works just fine and gives me a pulse ...
2
votes
4answers
201 views
Is it possible to have multiple ISR routines for a single timer in micro controller?
I have doubt that micro controller will support multiple interrupt routines for a single timer.
For example, single timer which interrupts at 5ms, 10ms, 1s etc. In my design I am using 3 timers: one ...
2
votes
2answers
104 views
Modify circuit to turn motor on/off multiple times per switch press
I purchased a timed air freshener kit which makes the motor spin when the switch (SW1) is pressed. I have created a schematic based on the diagram in the instructions (pdf).
simulate this ...
14
votes
2answers
397 views
How to synchronize two microcontrollers to micro-second accuracy?
I need to synchronize two micro-controllers so that they can measure the speed of propagating waves. The time delay measurements need have microsecond accuracy (error less that 1/2 of a microsecond).
...
0
votes
1answer
220 views
555 Timer 74LS192 IC Circuit
Our instructor gave us the assignment of creating a working schematic using a 555 Timer and a 74LS192 IC using 9 LEDs. The 9 LEDs will blink counting in seconds particularly 9 seconds then it's going ...
1
vote
2answers
305 views
High resolution system timer in STM32
I have some software running on an STM32F103 (I'd also like to be able to use the F4) where I'd like to be able to 'timestamp' events (such as interrupts on external pins) to the nearest microsecond ...
2
votes
1answer
102 views
Accurate Timer, follow up and How to?
In the question: Very accurate time measurement, Rocketmagnet show a circuit that is exactly what I need for a cub scout pinewood derby race track timer. I want to be able to dedicate a timer to each ...
-1
votes
2answers
98 views
Understanding timers
I'm studying timers for use in scheduling and embedded systems but I don't understand the detail, does the time count upwards or downwards? Is the timer like a hardware timer like the ones we learnt ...
0
votes
2answers
36 views
Should I use Counter1 to record time series data?
My Atmega328 will record data from an external sensor at around 100Hz over several minutes. Communication is done through I2C requests to the sensor. I need to store the time of measurement (relative ...
0
votes
1answer
26 views
Implement IR protocol using only one timer
I want to implement the transceiving part of an IR protocol for my Samsung remote on an nRF54822, using an ARM Cortex M0 core. The protocol is very much like the NEC Protocol, and is using a carrier ...
3
votes
1answer
155 views
Calculate exact timer frequency for ATTiny
Trying to wrap my head around these overflow timers for the ATTinyx5 (45 in this particular case). I seemed to have a great handle on it with the ATMega328 but I cannot get it to work the way I want ...
3
votes
1answer
142 views
Using Prescaler above 64 on ATTiny45
I'm trying to setup Timer0 on an ATTiny45 using the arduino-tiny core. TIM0_COMPA_vect works fine for prescalers 1,8 and 64, but 256 and 1024 cause the ISR to not fire. I am running the chip at 1MHz.
...
2
votes
0answers
61 views
ATtiny85, timer 1B does not work if COM1A1|COM1A0==0
I read the datasheet, and checked http://www.avrfreaks.net forum, but I cannot understand why on an ATtiny85:
...
4
votes
2answers
248 views
Building small, low-power pedometer/odometer with memory and time/date log
Background
I'm a researcher looking at the use of personal tracking devices and apps (like Strava app or Fitbit device) for cycling. At the moment I'm designing a simple experiment where I want to ...
0
votes
4answers
137 views
Timer on PIC18 not getting close to desired interrupt period time
I tried to setup Timer0 on a Microchip PIC18F46K22 so that it will trigger an interrupt and toggle an LED. However, it takes at least 42 µs for the LED to toggle.
At an increment rate of Fosc/4 (= 8 ...
2
votes
1answer
89 views
How do I momentarily ground a 3.3V signal (with a pull-up resistor) when power is first applied?
I need to momentarily ground a 3.3V signal that has a pull-up resistor on it when power is first applied.
This is feasible using a microcontroller or a push-button, but is there a "passive" way to ...
23
votes
4answers
1k views
Why would a modern digital clock rely on mains frequency?
I am in the military, stationed in Djibouti, Africa. We generate 240V/50Hz power on base, but some buildings also have 120V outlets, which I assume is transformed somewhere else on base, probably at ...
-6
votes
2answers
550 views
How does the 555 timer IC circuit work?
As a beginner to electronics I'm having a tough time understanding circuits that have a combination of different components, including the following timer circuit. Its based around a LM555 timer IC. I ...
5
votes
3answers
351 views
five month countdown timer circuit?
I'm a beginner in electronics, so I just have an idea in my head and don't know how to actually make it. I want to make a countdown circuit, for an event in next 5 month. The display format is like ...
7
votes
4answers
204 views
Can I achieve a one shot button without a 555?
I have a complex circuit, but my problem only relates to one small part.
I have a relay, which is energised by pulling the low side low using an NPN. I would like a pushbutton to operate the ...
3
votes
1answer
208 views
PIC interrupt based soft UART timing trouble
I've tried to implement a software UART on a PIC18F452 using TIMER0 interrupts and I can't get the timing working.
I'm using MPLAB ASM for compilation and the PICkit2 for programming.
...
3
votes
2answers
230 views
Use PWM and ISR at same time on AVR
Is it possible to use AVR PWM outputs and ISR interrupts at the same time?
I've got a project I'm trying to do on an ATMega328P and I need 3 PWM outputs but ALSO need to be able to use ISR interrupts ...
1
vote
1answer
64 views
Difference between Max Interface Clock and Max Timer Clock?
I am trying to use a timer from STM32F4 with ARM Cortex-M4 chip. I need to get the maximum frequency out of that timer for my ...
