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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26 views

PCF8574T I2C to 8bit Parallel

I want to connect 5 of pcf8574t on my AVR ATMEGA32L. One for LCD 2x16 and 4 for general purpose I/O. The question is: if i get an interrupt signal from one of 4 chips, how can i know which chip has ...
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0answers
14 views

Problem with Constant Off-time PWM/Variable Frequency on dsPIC30F2020

I'm using the Microchip dsPIC30F2020. I've been trying for the longest time to get some sort of PFM signal for my project. I see in Section 12.4.7 there is the ability to have constant off-time PWM ...
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0answers
25 views

STM32F4xx WFI unable to sleep due to SysTick Interrupt

I am trying to add some power conservation to our STM32F4xx powered device using its WFI sleep function. However, whenever I call the WFI function, the system is not being put to sleep (or rather, it ...
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1answer
39 views

Timing Delay Error

I am new to embedded system programming. I am working on clock using 8051 timer and interrupt.The delay is perfectly of 1s but when I run my clock with computer clock I loses 3-5s in 10min.I have try ...
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2answers
65 views

Choice of the appopriate conditional statement

I'm measuring the width of a PWM puls with the external interrupt: ...
4
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2answers
102 views

What is the difference between context switching and interrupt handling?

I'm an embedded developer. I haven't worked with RTOS/linux. I was going through RTOS concepts when I stumbled upon 'context switching'. I understand that when context switch occurs, all the registers ...
2
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2answers
54 views

Timer interrupt on stm32f103

I'm having a little suprise with timer interrupt on update event. I thought that if timer is configured to count up, update event will occure just after the overflow, i.e. when CNT will become equal ...
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1answer
79 views

External interrupt doesn't set flag bit

My goal is to measure PWM pulses. But to achive that I'm making baby steps, so my first goal is to set a pin when an edge of the PWM signal is detected. The PWM signal enters the microcontroller ...
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1answer
63 views

I2C hangs during loop

I have an arduino, accelerometer and a simple audio synthesizer circuit. My goal is to receive data over I2C from accelerometer to control the synthesizer. However I cannot get both the things to ...
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1answer
51 views

Clearing/acknowledging of level triggered interrupts

I am confused with the clearing/acknowledgement of level triggered interrupts in an SoC. When an interrupt is level triggered should the clearing be done in the interrupt controller or the bus ...
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0answers
44 views

How do I avoid a reset when using the watchdog in interrupt mode and changing the timeout?

I'm writing a program for an ATtiny85. I want to use the watchdog to wake up from power down in certain intervals. It all works fine as long as the intervals for a watch dog event don't change within ...
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2answers
60 views

Same Priority Interrupt on ARM Cortex M0

I have two two interrupts of the same priority; each has its own interrupt service routine: ISR_A and ISR_B. When interrupt A occurs, ISR_A executes... what happens if interrupt B occurs while ISR_A ...
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1answer
117 views

PIC32 does not get UART RX interrupts in xc32 Compiler

I'm trying to setup a UART channel on my PIC32 MCU (PIC32MX470F512). But the code does not reach the ISR at all. I have verified that the PPS (peripheral pin select) is configured properly and the ...
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0answers
34 views

Not entering ISR for timer 4 in stm32f4

I have coded for Timer 4 in a STM32f407vg discovery board. But while debugging the control is not entering the ISR. Please find the code below and help: ...
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4answers
93 views

Level vs edge triggering, usefulness of level triggering

Many processors / µCs / dev-platforms (BeagleBoard, Arduino,...) use interrupts. These can be triggered by the detection of: HIGH level RISING edge CHANGING level (either FALLING or RISING edge) ...
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1answer
64 views

Millis versus centis on AVR platform

I am building a device on the AVR platform. The device will need some timing information, so I was thinking of reimplementing Arduino millis-like functionality ...
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3answers
108 views

I'm trying to implement interrupt from RB pins. But it doesn't work

I'm new to PIC programming. I made a program to get interrupt from RB pins. but it doesn't work. My code is as follows: ...
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1answer
77 views

Two functions in the high priority interrupt

I'm using the PIC18F46k22 mcu and I'm using two function in my high priority interrupt routine: ...
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1answer
76 views

Are there platforms where disabling/restoring interrupts from ISR should be done differently than from non-ISR context?

I'm familiar with several real-time kernels: AVIX, FreeRTOS, TNKernel, and in all of them we have 2 versions of nearly all functions: one for calling from task, and second one for calling from ISR. ...
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2answers
50 views

Role of the MMU in a Page Fault Swap

When a virtual memory address outside the range of loaded into physical RAM is referenced and a page fault occurs, does the Memory Management Unit rely on DMA (Direct Memory Access) to swap the ...
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3answers
91 views

Returning from interrupts at a different location from where the interrupt occurs. (PIC16F877A)

Is there a way to return from interrupts at a different location from where the interrupt occurred in Microchip PIC16F877A? I have a problem where I need my code restarts at a specific point always ...
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1answer
36 views

Program aborts after ISR

First I am new to this and I signed in to get some help on this problem I have been having. I have done so much googling to figure this problem out and with no luck. I am trying to capture humidity ...
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1answer
45 views

Unexplained behavior pic port b on change interrupt

I am trying to configure the port b interrupt on change interrupts to work with a program I am writing with MC XC8 demo version. I am using a PIC16F628A I am using this code to initialize the pic for ...
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3answers
79 views

Catch both sides of a clock change PIC interrupt

I am trying to build an IR remote receiver using a PIC16F628A. To do that, I need to catch both the falling and rising edge of the external interrupt pin. From the datasheet it appears you can only ...
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0answers
47 views

LSM303DLHC data ready interrupt

I have a STM32F3-discovery board, and I have set up a little test. It just captures ALL input on GPIO3 and count them by channel. Then every seconds, I have a breakpoint with which I look at the ...
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0answers
48 views

8051 external interrupt INT0 issue?

How do I write an ISR greater than 8 bytes which is triggered by INT0?
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1answer
92 views

Measuring pulse length with ICP

I am trying to measure pulse length, with ICP (input capture pin) on Atmega8, coming from this circuit:. PINB0 is ICP pin on AVR. This is (most of) the code: ...
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2answers
251 views

STM32F103, Having trouble nesting interrupts

I'm trying to interrupt into a USART handler from inside an RTC_Alarm handler, but it doesn't work. I have set the NVIC: ...
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0answers
54 views

AVR TWI/I2C Not Responding

I use Twi module of AVR Atmega168 to talk to DS1307. ...
3
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1answer
87 views

SLEEP or busy-waiting. Which would service an interrupt faster?

I'm programming a PIC microcontroller to service two events via interrupts on a very time constrained environment. PIC microcontrollers allow a SLEEP mode which wakes the PCU on any external ...
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2answers
281 views

PIC18 xc8 compiler : how to resolve warning (335) unknown pragma “code”

I'm trying to compile this code to blink led with button interrupt, using xc8 compiler and PIC18F4550. I got those warning, so the code lines are ignored and the program doesn't work properly (by ...
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1answer
114 views

Implementing input capture correctly on a PIC

I'm using a PIC16LF1827 with the XC8 compiler in MPLAB X. I need to store the time between pulses that are coming from an external moisture sensor. The length of time correlates to the measure of ...
0
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2answers
119 views

Faster quadrature decoder loops with Python code

I'm working with a BeagleBone Black and using Adafruit's IO Python library. Wrote a simple quadrature decoding function and it works perfectly fine when the motor runs at about 1800 RPM. But when the ...
1
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1answer
155 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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122 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
125 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 ...
0
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2answers
112 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
90 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
44 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 ...
1
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1answer
88 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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67 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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1answer
230 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 ...
1
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1answer
54 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 ...
0
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1answer
61 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 ...
0
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1answer
115 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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0answers
63 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 ...
2
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2answers
168 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
187 views

AVR bootloader interrupt issue

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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1answer
96 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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16 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. ...