Interrupt Service Routine. A function which gets called in response to an interrupt signal.
0
votes
1answer
39 views
Can't operate relay's functionality in ISR function
In recent project, I have to operate my relay based on falling edge of Square wave. Here, falling edge detect by using interrupt. So, whenever Arduino detect falling edge using interrupt, ISR function ...
0
votes
2answers
51 views
ISR and multiplexing- time required to execute the code in Arduino
Below is an Arduino sketch for a basic animation, taken from the book Beginning Arduino by Michael McRoberts. Also, the connections have been shown. From what I have read elsewhere, this is the ...
1
vote
1answer
55 views
Volatile variable not updating from timer ISR
I know this is a problem that has come up many times but I can't seem to get this code fragment to update the count variable on an ATMEGA328P. I am using an Arduino Uno as a development board, with ...
1
vote
1answer
46 views
Arduino (weird) ADC problem
I'm trying to read to voltage output of module ACS712. Here is my problem: The module outputs a voltage around 2.5V, however, arduino sends the value "1023" to the PC. (Gives a reading of 5V).
...
0
votes
1answer
44 views
Software PWM implementation on ATTiny44 screws up timing functions
I've came up with a poor man's implementation of software-based PWM for the ATTINY44 and I'm kinda stuck now. It works but it screws up the timing functions badly (delay, delayMicroseconds) no matter ...
0
votes
2answers
20 views
Custom ISR triggering function/value
Is there a way to write a custom function which would be the mode/reason to trigger an interrupt. I have an analog joystick connected to my arduino analog pin. It reads a value of 689 on one end and 0 ...
1
vote
2answers
54 views
How time intensive or how long can an ISR be?
I would like to code my ISR to be time intensive or interrupt the main program for atleast 1 or more seconds. My goal is to verify that if I am reading a sensor in the main loop, would it stop reading ...
1
vote
5answers
95 views
Is possible to set a pin faster than digitalWrite?
I am currently using arduino library to logically set my digital pins high or low, but I just realized how slowly it actually sets those pins, which is especially problem as i am doing this in a ISR ...
5
votes
3answers
88 views
why does function affect my ISR?
I am currently running this piece of code:
main.ino
#include "speed_profile.h"
void setup() {
// put your setup code here, to run once:
output_pin_setup();
cli();
timer1_setup();
sei();
}
...
0
votes
1answer
38 views
Do ISRs have to be defined in top level Arduino program?
I'm currently attempting to implement some interrupts on an Arduino project. Looking through some of the examples, it appears that all the ISRs are defined in the top level Arduino program. I'm ...
0
votes
4answers
464 views
How to set up one second interrupt/ISR for ds3231 RTC
I am able to set up one hz interrupts using millis and other timers, but would like to do it instead using the RTC I have attached (DS3231)
I am not sure how I can do that. Can someone point me to a ...
0
votes
1answer
30 views
Having trouble using RTC if I set an ISR for a 1 second timer
I built a sketch using some timer ISR code to get a trigger every second. (for the Atmega328 chip I use the following code I got form the internets. It works)
It runs fine and I get a trigger/...
2
votes
3answers
91 views
What is the maximum length an Interrupt Service Routine?
In general, what's the maximum length of instructions that can be included in an Interrupt Service Routine?
The docs say an ISR should be "as short and fast as possible", but that's bit vague.
For ...
0
votes
1answer
39 views
ISR halts in DUE
I am using the following simple code to test the interrupt functionality of due:
void aMillion(){
for(int i = 0; i < 1000000; i++){
if(i % 1000 == 0){
Serial.print("m");
...
0
votes
1answer
52 views
Engine Speed Control Observation
I am using an Arduino Mega to control the speed of an internal combustion engine.
The speed is sensed via a Variable Reluctance Sensor (VRS) on the crankshaft. This signal is then converted into a 5V ...
1
vote
1answer
42 views
How to user timer interrupts for times longer than can TNCTx can keep track of?
I am trying to program my Arduino Mega 2560 to effectively create a PWM signal on any digital pin using timer interrupts and timer1. The pins will pulse a finite amount of times (not indefinitely). I ...
3
votes
1answer
106 views
how do I use interrupt service routines inside libraries and classes?
I'm trying to have a millis() timer run to emulate a hardware timer inside a library, but I'm having issues compiling the code. I want to have the callback (pseudo ISR) be part of the class, and not ...
0
votes
2answers
46 views
Interrupt numbering
I'm using an Arduino Mega and four of its interrupts. Each interrupt is only used to start/stop a timer, depending if it's rising or falling, so effectively runs the same function. Does anyone know if ...
1
vote
3answers
379 views
Breaking a switch case from an ISR
I'm struggling with something. My CPU sits in a switch case state machine like this:
switch(expression) {
case constant-expression_1 :
statement(s);
break; /* optional */
case ...
1
vote
1answer
117 views
Irregularly triggering an ISR using timers
I seek to call an ISR routine after a fixed time of 400us. This action needs to be done every now and then (in the range of 0.8-3.0ms). For that matter, I thought I'd set timer2 to CTC mode, use OCR2A ...
1
vote
0answers
141 views
Does Proteus simulate external interrupts properly using Arduino? I can't get them to work
I am trying to simulate an interrupt with an Arduino Uno in Proteus. This is the simple test code that I'm using:
void introutine()
{
digitalWrite(13,HIGH);
}
void setup()
{
pinMode(13,OUTPUT);
...
0
votes
2answers
139 views
ISR executes twice if data coming through SoftwareSerial
I am using Arduino Pro Mini to get GPS info from a u-blox NEO-M8N chip and display it on a Adafruit OLED display. NEO-M8N has a PPS(pulse per second) output which is aligned to GPS's second. Because ...
1
vote
1answer
53 views
Using AVR Timer Within an ISR
I'm trying to create an ISR which operates for 15 seconds when a particular button is pressed. I'm attempting to use the AVR functions on my Arduino Uno to start counting when it enters the ISR, then ...
4
votes
2answers
2k views
Why the need to use the volatile keyword on global variables when handling interrupts in Arduino?
I am familiar with the keyword Volatile being used to declare variables that are shared among multiple threads on a software application (basically on a multithreaded application).
But why do I need ...
-1
votes
1answer
202 views
Arduino Due interrupt is taken but not executed completely
I tried to build a simple l-meter with my arduino due. I programmed a simple frequency meter with one timer and one counter. The timer takes an interrupt each 10s, 100ms, 10ms and 1ms. But ones the ...
1
vote
1answer
223 views
Hardware Interrupt Triggered Randomly
So there is this pretty generic part of my project that involves triggering an ISR that will flip a boolean value. I have set up the software side like so:
void setup() {
attachInterrupt(...
1
vote
1answer
122 views
Timer (or other) interrupt happens while servicing an interrupt - how to accurately handle the second one?
This seems like a simple question but I'm not finding an answer so far: at a high level, say I have a timer interrupt and some input interrupt. The input arrives, the ISR is entered, interrupts are (...
0
votes
1answer
280 views
Usage of SPI inside an ISR
I learned, that SPI-code uses interrupts. So is it true then, that I can't use SPI related code inside an ISR?
Background: I want to capture one or more revolution speeds with an MCP23S17. I rewired ...
1
vote
2answers
189 views
Is it correct to use pulseIn() in ISRs?
Since it is not right to use millis() in an ISR to calculate duration of the input, Is it correct to use pulseIn()?
0
votes
1answer
125 views
UNO Timer 1 CTC mode not resetting TCNT1
I'm trying to set up timer 1 to run an isr in CTC mode. no matter what i set OCR1A to it always executes at the same frequency and if i print out TCNT1 I get values higher than OCR1A.
here is my Code
...
1
vote
1answer
73 views
Making a composite waveform using a single TIMER interrupt
I'm writing software for a laser tag gun, which under the system we use needs the output waveform to be a carrier wave of 57600Hz with a signal wave of 1800HZ for about 50ms
Using the Tone library (...
0
votes
1answer
43 views
The code of ISR executes twice
i am using Arduino Mega.. ANd this is the code:
void bump(void);
void setup()
{
pinMode(19,INPUT);
attachInterrupt(4,bump,HIGH);
pinMode(13,OUTPUT);
}
void loop()
{
}
void bump()
{...
2
votes
1answer
254 views
Why does timer ISR not execute?
This is my code which I have written as a library
#include "avr/interrupt.h"
#include "Arduino.h"
#include "AllTimer.h"
AllTimer::AllTimer()
{}
void AllTimer::dofun(void)
{
//TIFR1 |= _BV(...
7
votes
2answers
1k views
Arduino interruption (on pin change)
I use the interrupt function to fill an array with values received from digitalRead().
void setup() {
Serial.begin(115200);
attachInterrupt(0, test_func, CHANGE);
}
void ...
1
vote
3answers
564 views
ISR executes even though an interrupt is not triggered
I am trying to implement a function queue scheduling system. INT1 is connected to a button and int1task causes an LED to flash.
typedef void (*funcptr)(void);
TPrioQueue *queue = NULL;
void int1ISR()...
6
votes
2answers
1k views
How to update a variable in an ISR using Timers
I'm trying to check the frequency of Timer3 using a counter. The value of the counter, declared as volatile, is incremented in the ISR and every second the sum is shown in the main loop and the value ...
1
vote
4answers
248 views
Atmega168 breaking out of ISR
I wrote a code to handle an ISR triggered by UART input. I'm looking for 2 characters or more. I can handle extra characters and garbage values, but problem arises when I get less than 2 chars, ...
0
votes
2answers
105 views
Atmega168 interrupt error handling
I'm using an Atmega168 in a project that involve using the ISRs from multiple sources. I have an ISR hooked up to an external button and a timer, to use it as a reset button after a predetermined hold ...
1
vote
0answers
823 views
attiny85 in sleep mode failing to wake properly [closed]
For my attiny85, I'm having trouble getting it to sleep and wake up cleanly.
I have a sleep mode with a watchdog timer that wakes every 8 seconds, or when interrupted. And then when that has repeated ...
3
votes
3answers
3k views
Is `millis()` affected by long ISRs?
I have a project that uses timers and interrupts frequently. A lot of CPU time is spent handling ISRs over an extended period of time.
Would this affect code inside the main loop that relies on the ...
10
votes
2answers
566 views
Are function pointer assignments atomic in Arduino?
The following snippets are from TimerOne library source code:
// TimerOne.h:
void (*isrCallback)();
// TimerOne.cpp:
ISR(TIMER1_OVF_vect) // interrupt service routine that wraps a user defined ...
6
votes
1answer
4k views
Is volatile needed when variable is accessed from > 1 ISRs, but not shared outside ISRs?
It's clearly documented that when global data is shared with an ISR and the main program, the data needs to be declared volatile in order to guarantee memory visibility (and that only suffices for 1-...
1
vote
1answer
1k views
Arduino Uno R3 ISR does not work on pin 2?
I have an Arduino Uno R3. I have a paddlewheel waterspeed sensor that I use on an ISR on pin 2. The power supply is approximately 8v stepped down to 4.92v with a circuit yanked from the phone charger. ...
18
votes
3answers
2k views
Can a function be called automatically when an input changes?
Currently, my sketch is checking an input pin every time round the main loop. If it detects a change, it calls a custom function to respond to it. Here's the code (trimmed down to the essentials):
...
