A mechanism for the control of program flow in a computer. When interrupted a computer saves it's present operational state and changes to execution of code that is dependant upon which interrupt was generated. Interrupts can be either Hardware sourced or software sourced. It is an alternate ...

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36 views

Timer Interrupt for Case Statement

I have 3 states for a motion control system in a case: Accelerate, Steady, Decelerate. We start in the the accelerate case and when certain conditions are met, we move to the next state, etc. How can ...
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2answers
62 views

I2C on atmega168/328 using interrupts

I have the following I2C configuration with an ATmega168 (1 MHz) as the master and an Arduino Uno (16 MHz) as the slave. The command for the LED connected to the slave comes from the master and ...
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3answers
56 views

Appropriate Method of Counting counts from a Quadrature Encoder

I'm using an Mbed to drive a DC motor which will follow a trapezoidal trajectory. What is the most appropriate way to determine position from the quadrature encoder? Should I use interrupts, or is ...
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2answers
89 views

How to correctly wire an interrupt pin, clock pin, PWM pin, SPI pin

I've a question about how to correctly wire some microcontrollers pins. In particular: Interrupt pin on microcontroller (pull up/pull down resistor and with which value) Output clock pin from a ...
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1answer
60 views

Atmega Microcontroller interrupt delay function on button press

I am using Atmega32A and I have 2 LEDs. Here's step by step what I want to do When the MCU is powered, I have one LED lit (PC0) When click on a button (PD6) the second LED at (PC1) is lit and the ...
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2answers
47 views

Two limit switch signals affecting each other

I'm trying to make circuit which will allow me to sense some platform presence at the ends of some rail. I'm using the limit switches, here is schematic: SENS-* signals connected to MCU pins, that ...
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3answers
478 views

What's the actual difference between Edge sensitive and Level sensitive interrupts

Currently I'm working on a C8051F120 MCU where External Interrupts can be defined in two ways: Edge sensitive (Falling) Level sensitive (low-level) In level-sensitive interrupts as soon as the MCU ...
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2answers
81 views

Determine input frequency of square wave w/ ICR in Atmega328p

I'm trying to obtain the input frequency of a square wave using the input capture register of an Atmega328p. So far, it works sporadically -- which is to say, when I input a 75 kHz square wave, the ...
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1answer
53 views

PIC16 I2C interrupt does not occur if serial port enabled

I'm using a PIC16F1825 mid range PIC and I've used it with a UART and SPI for a good while without issues. When I added code to handle I2C (instead of SPI - it's either one or the other on this PIC) I ...
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0answers
11 views

Where is documentation on Arduino's Internal Interrupts? [migrated]

First time arduino programmer here...however I have programmed the TI MSP430 in the past... I am trying to figure out how to configure internal Interrupt Vectors on this Arduino Uno. In the Arduino ...
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3answers
127 views

Computer peripherals to immediately (<5ms) detect digital input state change in C# programs

The C# application I'm working on needs to be able to be able to call a function within 5 milliseconds of a digital input signal's state change (0V = off, 5V = on). Rather than using software to ...
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1answer
15 views

ATtiny861 pin change interrupt on PA.2: error in datasheet?

I faced with some confusion in subject datasheet: In one section PA.2 should be masking by PCIE1 bit as PA.2 is PCINT2 input and it should be within PCINT[7:0] and PCINT[15:12] range: On the other ...
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0answers
32 views

Configuring the rate of Timer interrupts for the STM32F4xx Discovery Board

I'm working on a project with the STM32F407 board and Keil, and as part of a larger project I'm working on I need to configure a timer interrupt. Eventually it will run at around 46 kHz, but for now ...
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1answer
50 views

Simple Interrupt Handling program?

I'm new to Embedded programming and I'm trying to understand how Interrupt handlers work in different contexts/scenarios. I just want to know how a interrupt handler would work in the following ...
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0answers
22 views

Systick Timer problem

I am trying to use the systick timer to update a variable which stores millisecond elapsed on a STM32F051 in Coocox ide 1.7.8 . I also want I2C and UART communication in my project. I managed to get ...
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0answers
43 views

STM32F051 TIMER2 INTERRUPT PROBLEM

I would like to get TIMER 2 working for stm32f051 microcontroller in coocox IDE(1.7.8) . The problem i am facing is that as soon as I enable the intrrupt for TIMER 2 using NVIC_EnableIRQ(TIM2_IRQn) ...
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1answer
58 views

AVR global variable modified by interrupt not persistant

Using an ATmega328p, I'm running into a problem when I make an interrupt (INT0 or INT1) active, the code will execute just fine (MusicOnLed and FadeOnLed functions will execute), however as soon as I ...
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0answers
58 views

PIC18: I2C with external triggered interrupt stuck in ISR

I am trying to implement a simple, external, pushbutton trigerred I2C communication between a PIC18F46K22 and a ST LSM330D MEMS sensor. I tried to find straightforward libraries for the easy ...
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2answers
99 views

Arduino analog interrupt LDR

I am using an LDR on an Arduino Pro Mini with an analog interrupt. The Arduino goes to deep sleep when there is no light or it's not busy: Sleepy::powerDown(); ...
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1answer
66 views

Atmega2560 Usart Interrupt problem

When I send any data from serial port, RX pins are flashing but ISR is not running. Here is my code. ...
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2answers
190 views

Interrupt fails to change variable, how so?

Problem was virtually undebuggable, the interrupt that was changing a variable would randomly fail to do so, with no apparent pattern; within interrupt code variable would change but outside of it the ...
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1answer
87 views

PIC18 High Priority Interrupt doesn't Interrupt the Low one (xc8)

I was trying to learn and implement the priority property of interrupts on PIC18F46K22 uC. I use MPLABX and XC8 compiler. In my code (transformed from a sample code), I have one external interrupt ...
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1answer
41 views

PIC18 IO polling

I just recently decided to migrate an existing design which was based on Interrupt on change pins to standard IO polling due to some constraints in the part that I was using. I am trying to figure out ...
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0answers
30 views

PIC18 Interrupt on change vs polling

I am currently using a PIC16 part whose entire PORTB ports have the Interrupt on Change feature. I am forced to migrate to the PIC18 part as I gain more GPIOs but only the upper 4 bits of the PORT B ...
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1answer
47 views

Interrupt on the XMEGA

I have 3 buttons connected to PIN1, PIN3, PIN5 of PORTA of an XMEGA. If pushed they deliver a falling edge. I'm try to generate interrupt using those buttons, I started with one, here is what I ...
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1answer
93 views

AVR Timer1 OCR1A controls TIMER1_COMPB_vect interrupt!

I was struggling with timer interrupts in my project. I couldn't make it work properly. So I decided writing a simple code and I saw a very interesting case. ...
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3answers
91 views

PIC32, XC32, timer interrupt vector not entered

I have the below timer 5 interrupt vector that is not entered, even when both the corresponding Interrupt enable bit for timer 5 is set, and the corresponding interrupt flag for timer 5 is set. Here ...
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1answer
61 views

PIC18f8722 interrupt problem

I did many research but couldn't find out what the problem it is. Actually my code as below. I am trying to implement a code in C with XC8 compiler. To enable a sentence on the LCD of the board ...
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1answer
50 views

toggling a pin using the hardware compare feature of timer1 AVR

This link - says: "In CTC mode, you can also trigger interrupts, but it is also possible to not use interrupts and still toggle an output pin. Using it this way, the functionality occurs ...
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1answer
50 views

Valid use of ISR_NOBLOCK

I am using two timer interrupts: TIMER0_OVF triggered every 12 ms, with its ISR only polling a pin, conditionally setting a flag and incrementing a value, so it ...
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votes
3answers
104 views

AVR-C turning led off after number of blinks with interrupts

so what I am trying to do is that I am trying to make the led blink for a certain number of times before it turns off. I want to avoid using delays so I tried utilizing the interrupt and I also used a ...
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2answers
96 views

UART interrupt problem on LPC1788

I wrote a code ...
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1answer
89 views

Attiny10 not triggering timer overflow interrupt while simulation (Atmel Studio 6)

I have problems simulating the timer overflow in Atmel Studio 6. The code is for an Attiny10 and looks like below. As far as I know I set all the neccessary bits to enable the counter (which works in ...
2
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3answers
96 views

Interrupt question ARM?

I often see something like this void UART2_IRQHandler(void) __irq, and I wonder why __irq is used when declaring interrupt handler, is it required or handler can ...
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1answer
88 views

UART Interrupt won't work

I have a problem when trying to test send and receive lines on RS485 communication, anyone know what may cause a problem here? It works without interrupt but with interrupt won't work. I am working on ...
1
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1answer
121 views

Determine if button press triggered wakeup from STOP mode with STM32F0

I'm using an external interrupt triggered by a button press to wake up an STM32F030K6 from STOP mode. I was wondering if there's any way of distinguishing, within the interrupt handler, a button press ...
0
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2answers
106 views

intel nuc gpio access from ubuntu

I want to implement Interrupt Request via GPIO on Intel NUC d34010wkb. Are there any accessible GPIOs on board and how to access them? If there aren't any accessible GPIOs then what could be a ...
2
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4answers
567 views

Understanding interrupts and software button debounce

I'm quite new to AVR programming (avr-gcc). To react on button-press, I am using a PCINT ISR with the internal pull-up resistor enabled like this: ...
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1answer
124 views

Stop timer set new value and start again AVR (Interrupt)

I have AVR MCU. I am playing with timer now. What I need ? I have timer counting up with some frequency. In each interrupt I am incrementing variable, and somewhere I need to check value of this ...
9
votes
3answers
1k views

Software interrupt vs function

After about 3 years of working with MCUs still I don't know what's the use of Software interrupts? I have done several jobs with STM32 and I have never used the software interrupts. Indeed this is a ...
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0answers
49 views

Interbytetiming ,kwp2000,Fastinit

How to set interbyte delay, I should be able to get 25ms low and 25ms high and later the data bytes at 10400 baudrate, implementing kwp2000 protocol. When I send bytes ...
8
votes
4answers
746 views

Interrupt handling in microcontrollers and FSM example

Initial question I have a general question about the handling of interrupts in microcontrollers. I am using the MSP430, but I think the question may be extended to other uCs. I would like to know ...
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0answers
25 views

Expanding the Interrupt Structure of an 80286 System using a 74ALS244

Can we initiate a type 2 interrupt(or Non-Maskable Interrupt) even though Device 1 never issues an interrupt request? And how to do it? I think we should connect the interrupt request of type 2 ...
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3answers
62 views

How to get equal number of clock cycles before ISR on an AVR

While writing a time critical piece of code for an Attiny13, I figured I could use the rising edge of an input as a trigger to read in some self clocking data. However, the number of clock cycles ...
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1answer
87 views

STM32 and SDCard: space management

My task is to gather measurement from peripheries of STM32F4 on SDCard and I started reading about this. Could you double check if I'm correct: Single block memory on my SDCard is 512 bytes, so ...
1
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1answer
89 views

Testing the ADC interrupt on dsPIC33EP256MC506

I have a Microchip MCLV-2 development board intended for controlling small rating BLDC and PMSM. I am trying to develop a simple program to test the ADC interrupt. Basically, I want the program to ...
1
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0answers
79 views

PIC32 Input Capture Module

I'm trying to use the input capture module on a PIC32MX250F128B to measure the frequency of a square wave. The results I'm getting are both inconsistent and incorrect. All I'm trying to do here is ...
1
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1answer
98 views

Interrupt within an interrupt on a PIC18

I am working on code for an external interrupt from RB0 on a PIC18F4550. When an interrupt is detected on RB0, timer0 is activated. I then need to watch for timer0 overflowing. If it does, then the ...
2
votes
1answer
308 views

STM32: Timer interrupt works immediately

This is code for timer in my project on STM32F429: ...
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0answers
19 views

program stops in non maskable interrupt when initializing time interrupt

I am using RX62N microcontroller and am new to it. In this i was trying to blink the led using interrupt(compare match timer) but after the initialization it always goes to the non maskable interrupt ...