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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35 views

What is a good strategy to read many button inputs while still doing USB?

I am trying to design a USB joystick with many different buttons. The board I am using right now has an ATmega32U4, USB port, and 16 I/O pins. I am using LUFA for a USB stack. I know that I can get ...
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0answers
10 views

EINT ( Ext interrupt ) of LPC2138 is not getting low

I am using interrupt for touch sense TFT LCD application, where touching on LCD makes transition (on EINT pin) from high to low ( 3V to 0V ) and touch sense controller is through SPI interface to ...
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2answers
26 views

Tm4c nested uart interrupts- does each com finishes it's run before the next one executed?

Board: Tiva™ C Series TM4C1294 EK-TM4C1294XL My program is listening to 2 UART ports (UART 3 and 7) I've encounter a problem that I'm losing some bytes received and I'm suspecting that this issue ...
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1answer
37 views

AVR: Interrupt build error

I am trying to learn how to use interrupts for a project using an Attiny85. I have written a simple program from what I have learned from tutorials. However when I try to build the program in Atmel ...
3
votes
2answers
123 views

Race condition in AVR timers

I'm trying to implement a global timer, so that I can call time_us() anywhere in program and the function will return microseconds since program start. I've done this using TIMER2 (8-bit clock) and ...
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1answer
87 views

Can't get AVR pin change interrupt to work

I'm trying to get a pin change interrupt on an Attiny2313 to work but i'm stuck, the interrupt is not triggering. I'm using the following code in main(): ...
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2answers
44 views

CCS PIC C: What is the difference between #INT_TIMER0 and #INT_RTCC?

In CCS PIC C Compiler, there are two interrupts and both are tied to Timer0 overflowing. These are called #INT_TIMER0 and #INT_RTCC. What does RTCC mean and is #INT_TIMER0 not sufficient?
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2answers
323 views

NVIC on ARM CPUs

Can we look at NVIC peripheral on ARM CPUs like some sort of thread? Main application is executing, and at the same time NVIC peripheral doing her own work? Or all of that is single thread ...
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0answers
83 views

Arduino UNO R3 (clone), ESP8266, false interrupts from opto-interrupter

simulate this circuit – Schematic created using CircuitLab i'm facing false interrupts from opto-interrupter scavenged from old mice, when wifi module ESP8266-01 is connected to arduino. ...
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0answers
42 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
69 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
63 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
94 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
74 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
48 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 ...
4
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3answers
488 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
96 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 ...
2
votes
1answer
68 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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3answers
130 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
17 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
36 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
53 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
30 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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50 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
61 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
72 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
129 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
71 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
197 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 ...
2
votes
1answer
122 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 ...
0
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1answer
43 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 ...
0
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0answers
37 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 ...
0
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1answer
53 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 ...
0
votes
1answer
141 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. ...
1
vote
3answers
128 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 ...
0
votes
1answer
72 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 ...
0
votes
1answer
51 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 ...
1
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1answer
53 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 ...
0
votes
3answers
114 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 ...
0
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2answers
123 views

UART interrupt problem on LPC1788

I wrote a code ...
0
votes
1answer
105 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
votes
3answers
103 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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votes
1answer
102 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
vote
1answer
149 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 ...
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votes
2answers
146 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
votes
4answers
728 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: ...
0
votes
1answer
152 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
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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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votes
0answers
52 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
768 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 ...