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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48 views

STM32F1 troubles with a timer

I'm having some troubles with setting up a 1 second timer on STM32F103 mcu. I have set Timer 2 to have a prescaler of 1099 and a period of 65514, so I'm expecting to have a 1 second interrupt rate: ...
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33 views

Is USB UHCI polling-based or interrupt driven?

I've had a discussion with some colleagues whether USB is polling based or interrupt-driven. Some claim USB keyboards involve larger overhead than i.e. PS/2 keyboards due to the requirement of former ...
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1answer
37 views

Why does my Arduino DUE not recognize my external interrupt?

I'm simply trying to get my Arduino DUE to toggle a pin based on an external clock. I have a 14.31818 MHz Oscillator that is ...
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2answers
64 views

Calculating how many times TIMER1 will overflow

I'm trying to understand how to set up an overflow interrupt on ATmega328 TIMER1 to measure a frequency. I'm feeding pin PD4, which is where TIMER1 is externally clocked, with a 503kHz square wave ...
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2answers
58 views

ARM cancel execution of pre-empted interrupts

I can't seem to find an answer to this in google or the Definitive guide... Is it possible to from one interrupt, cancel the return to any pre-empted interrupts? For example, I have an ISR which is ...
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1answer
35 views

What is the danger of using interrupt pre-emption in ARM

I am working on a system which uses about 4 interrupts. I can clearly define a priority from one to the other. For example, I feed SPI transfers with DMA requests and operate a USB interface which ...
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1answer
36 views

Input interrupt pin associated with TIMER1 on ATmega168

A few days ago I came across the source-code for this ATmega168 based Inductance Meter from Dan's Workshop Blog. Below is the code that I believe sets up an ATmega168 interrupt to measure an external ...
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29 views

LPC2148 + Eclipse + yagarto + openOCD. Issue with the interrupts

I'm using 'Eclipse-Indigo' + yagarto + 'openocd-0.7.0' setup for a project on LPC2148. I've set up the environment properly. I'm able to compile, link and debug the project. I've configurred Timer0 ...
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48 views

STM32F103 Systick Interrupt stopped working when debugging in ram - (Coocox IDE)

I tried debugging my code in ram in order to increase the flash's life (only rated at 10k writes minimum) Anyways, I have tied the boot0 and boot1 pins to 3.3v and set the compiler to debug from ram ...
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1answer
44 views

The same flag for an interrupt

I think I'm mixed up a bit in NVIC of stm32 MCUs. I took a look in the SPI.h of the STM32F10x standard peripheral library. I don't know that why while there is ...
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1answer
48 views

Clearing Flag Bits By Writing 1

Most of the interface devices have various flag bits (that can also raise interrupts if that functionality is provided) used to check the status of the device/operation. Usually they are cleared by ...
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1answer
39 views

NRF24L01+ IRQ Issue

I am testing the functionality of NRF24L01+ and for my purposes I have configured it as PTX, No Auto ACK. I am able to communicate with the chip just fine and able to configure all the registers ...
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44 views

Spurious interrupts using switches on a Raspberry Pi

I have two switches connected to GPIO pins on a raspberry pi. One side of each switch is wired to +3.3v. The other side is connected to an input pin via a 330 Ohm resistor, and each input pin has a ...
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2answers
89 views

Interrupt Management - Large AVR Projects

This is for the more experienced one's out there. I am currently involved with a large AVR project (using ATMega328) and it's getting confusing with respect to interrupts. The project involves ...
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1answer
58 views

AVR bootloader restarts on interrupt

For a quite while, I've been using an avr ATmega324PA controller and Atmel studio to write the programs. we wrote a TCP bootloader. It works fine without any interrupt. Later we did add an external ...
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62 views

The GPIO External Interrupt doesn't work

I have written this program for GPIO External Interrupt but it doesn't work. look at the program: ...
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14 views

uC MPC5646CRM Interrupt source address

I am using an Embedded development software that needs the address of ISR in order to perform Interrupt. I am using MPC5646CRM Micro-Controller. The datasheet tells about the calculation of address. ...
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1answer
121 views

The LED blink even when I don't press the button

I have written a program in Keil for Blink a LED via External GPIO Interrupt. Ok, know I want to say you that how configured it in STM32CubeMX: At first, I enabled and configured RCC as you can see ...
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1answer
61 views

avr-gcc timer overflow interrupt handler in inline assembly

My current project involves producing 200KHz PWM waveforms using timer 1 in fast PWM mode. I would like to increment a 16-bit counter every time the timer overflows (every 5μS) ...
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1answer
68 views

AVR USART Random Behaviour

I seem to be getting random character in my USART output with an ATMEGA8 uart.c ...
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1answer
133 views

Can not jump to Timer interrupt function in STM32F4 discoverty

I made a code to call Timer2 interrupt function like this : ...
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1answer
87 views

To Clear or not to clear ARM Cortex-M NVIC interrupt pending

Do I need to clear the pending status of an interrupt in the interrupt service routine of an ARM Cortex-M0 MCU? Could not find information on this on the web.
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1answer
275 views

Stm32 Event and interrupts

I started studying interrupts on stm32 specifically the stm32f4 discovery board. i found this example in which you have to press the button to start the interrupt and push it again to stop it. In ...
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1answer
50 views

AVR- state change of a pin to generate an interrupt [closed]

I need to produce external interrupt whenever there is a change in state of a pin. When the pin goes from high impedance state to ground or from ground to high impedance state, an interrupt must be ...
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2answers
101 views

Periodic timer (64Hz) with ARM processor and (embedded) Linux

I want to call a function 64 times per second with a ARM processor which is running linux. (ex: Rasberry Pi or Freescale i.mx6). Ideally, I don't want too much jitter. I want to perform a task ...
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1answer
87 views

Is there a way to avoid an infinite loop and reduce CPU power consumption when using PIC and timer0 interrupt?

I have made a simple program that runs on a P12F629 microcontroller, using MikroC. I need ...
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1answer
28 views

How can I achieve a third interrupt priority level on 8052?

Most standard 8052 platforms allow the user to configure interrupts to be of two possible priorities: higher, during which any pending interrupt must wait, and lower, which can be interrupted by the ...
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1answer
54 views

How to detect which timer interrut called callback when using ASF?

I have a general function, which gets passed among others a timer. It initializes the timer using common callback function: ...
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1answer
66 views

Arduino: Generating time critical signals with interrupts

I have some problems to fully understand how interrupts on e.g. Arduinos/AVR are used in practice. Lets assume I want to generate a time-critical signal like PWM and at the same time be able to ...
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2answers
533 views

ISR - to flag or not to flag?

From what I read on the internet we should respond to interrupts as quickly as possible, when programming microcontrollers; and that flags should be avoided because they tend to compound over time. ...
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1answer
270 views

Global variable in AVR interrupt routine

I am writing a code with interrupt routine. For debugging the code am using UART. So, here is the snippet: ...
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0answers
89 views

Cortex M3 GPIO Interrupt won't trigger

I have set a pin on a Cortex M3 to act as an rising-edge triggered interrupt and it's not firing for some reason. What it should do is receive a 1Hz pulse, trigger an interrupt and start a 12.8Khz ...
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1answer
158 views

Multiple simultaneous Interrupts PIC 16F88

I'm new to PIC microcontrollers ( I have some experience with Arduino but wanted some "real" experience =P ). I got myself a PIC16F88 and I now intend to make a simple robots who's 2 DC motors are ...
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1answer
597 views

AVR SPI slave with interrupt

For a project I want to have two microcontrollers talk to each other via an SPI interface. I wrote the following code for the slave: ...
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63 views

Application of intel 8253 timer

8253 timer works in 6 different modes namely interrupt on terminal count, hardware-retriggerable one shot, rate generator, square wave generator, software triggered strobe and hardware triggered ...
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1answer
100 views

Two interrupts for a single operation

I am using infineon XC866-1FR controller for my project. For the motor control, I am in need of exciting the coil by the combination of two external interrupts(external interrupt 1 && external ...
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1answer
125 views

Netduino Interrupts Affected By PWM - Diagnosis of Issue

I've got a funny problem with interrupts and PWM signals that's causing false interrupts to trigger. What exactly is happening is that I'm using a hardware debounced quadrature rotary encoder. The ...
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2answers
472 views

Attiny85 hardware interrupt unreliable, 433 MHz remote

SCROLL DOWN TO SEE THE SOLUTION (UPDATE II) ORIGINAL POST: I am currently building a 433MHz remote with two buttons. The remote is controlled by an Attiny85v(8MHz). Sadly it does not work very ...
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4answers
221 views

Available Guidelines for Interrupt Driven Processing

Are there any available guidelines for the amount of code to have in a critical section of interrupt driven processing? My personal rule of thumb is that the critical portion, (i.e. that between ...
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3answers
241 views

Good flag practices - energia msp430

I'm making a program for the msp430 using energia launchpad, the first code that I had is the following: ...
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1answer
108 views

Identification of hardware interrupts in microprocessor 8085

I am familiar with the RIM and SIM instructions that are available in the instruction set of microprocessor 8085. And thus I can enable RST 7.5 and RST 6.5 interrupts using SIM instruction and EI ...
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1answer
82 views

Things to do with ISR

I have an ISR that increments a counter every 5ms if the switch is pressed. If the counter becomes 200 then do Reset. I plan to add more functions to be called from the counter value. After a few ...
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1answer
174 views

Interrupt Service Routines and I2c together

I would like to ask a question that has been on my head for a while I have done coding small ISR's for pic and AVR controllers and i have successfully tested them on board.And i have just learned ...
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1answer
87 views

Saving the last value used in an ISR

I am using a level-triggered interrupt. During the interrupt OCR1A increases and the servo moves. I want to save each value of OCR1A when the pin returns to its previous level. So far I have only been ...
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2answers
182 views

How can I wake up an ATtiny84 microcontroller at specific time of the day?

I am trying to create an alarm that wakes up at a certain time and does a series of instructions. To set the times that it wakes up, I am going to use the headphone of an Android device to send ...
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1answer
43 views

LM393N with hysteresis and potentiometer

I am having a bit of a problem with this next circuit: The problem is, when there is 0V at the base of Q1 and when the potentiometer is set close to 100 kOhm. Because of the hysteresis set on LM393N, ...
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1answer
153 views

Task handling in firmware

I would like to get an advice on handling tasks in a firmware. I have 3 major tasks to do: Scanning for whether a switch is being pressed or not. Data transmission via SPI - To EEPROM Data ...
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1answer
970 views

STM32 Rotary Encoder with Hardware Interrupts

I'm trying to get a rotary encoder working on my STM32. I have channel A & B being pulled up to 3V and debounced with 1uF capacitors. The board has channel A & B connected to PA11 & ...
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2answers
215 views

TXE bit won't clear UART ARM M0

I'm trying to get UART working on a STM32F0 part and can't figure out the interrupts. According to the reference manual ...
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1answer
179 views

STM32F207 I2C errors

I am learning embedded development on the STM3220G-EVAL board with the STM32F207 microcontroller. I am testing the I2C interface by interfacing the two I2C2 and I2C3 modules on the same chip and ...