DUE problem with micros() inside interrupts

cmaglie · March 2, 2013, 10:54am

submitted as a new issue:

github.com/arduino/Arduino

Possible bug in micros() when called inside ISR? (Due)

opened 10:54AM - 02 Mar 13 UTC

closed 11:43AM - 03 May 13 UTC

cmaglie

Component: Core Type: Bug

Forum topic: http://arduino.cc/forum/index.php/topic,148161.msg1136944.html#msg1…136944 ``` I had used the function micros() inside an interrupt, and sometimes it seem not work fine in arduino due. I would like to acquire the frequency (or time beetwen rising edge, i.e. Period) of an input signal on pin 28 (in Arduino due). The signal is a square wave 0/3.3V with PWM 50%. For example I set the frequency to 2000Hz ( period of 500 micro second ) with a function generation. this is the simple code: volatile unsigned long time, Time1, Time2, Period =0; volatile int i=0; int Signal=28; void setup() { Serial.begin(9600); pinMode(Signal,INPUT); attachInterrupt(Signal,InterruptSegnaleGiriT,FALLING); //Interrupt on Falling Edge } void loop() { if(Period<490 || Period >510){ Serial.println(Period); Serial.println(Time1); Serial.println(Time2); Serial.println(""); } void InterruptSegnaleGiriT(){ time=micros(); if(i==0){ Time1=time; i=1; return; } if(i==1){ Time2=time; Period=(Time2-Time1); i=0; return; } } If the function micros work fine, this code does not print anything. The problem is that sometimes the Period print is 1500 micro. While sometimes Period print is a number near to the limit of an unsigned long, maybe the Time1 is greater than Time2. I Have try to put the code on arduino uno, the code work fine!!! Maybe is a bug on Arduino due micros... ```

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DUE problem with micros() inside interrupts

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