کد اولیه ای که تابع اینتراتپ وقفه در آن استفاده شده است به شرح زیر است که برای شمارش دور و فرکانس استفاده میشه :
// read RPM


int half_revolutions = 0;


int rpm = 0;


unsigned long lastmillis = 0;


void setup(){
Serial.begin(9600);
attachInterrupt(0, rpm_fan, FALLING);
}


void loop(){


if (millis() - lastmillis == 1000){ //Uptade every one second, this will be equal to reading frecuency (Hz).


// detachInterrupt(0);//Disable interrupt when calculating


rpm = half_revolutions * 60; // Convert frecuency to RPM, note: this works for one interruption per full rotation. For two interrups per full rotation use half_revolutions * 30.


Serial.print("RPM =\t"); //print the word "RPM" and tab.
Serial.print(rpm); // print the rpm value.
Serial.print("\t Hz=\t"); //print the word "Hz".
Serial.println(half_revolutions); //print revolutions per second or Hz. And print new line or enter.


half_revolutions = 0; // Restart the RPM counter
lastmillis = millis(); // Uptade lasmillis
attachInterrupt(0, rpm_fan, FALLING); //enable interrupt
}
}


// this code will be executed every time the interrupt 0 (pin2) gets low.


void rpm_fan(){
half_revolutions++;
}

حالا اگر من به همین کد کارت حافظه هم اضافه کنم که در زیر آوردم برای ذخیره داده ها دیگه فقط 25 تا داده را در سریال مانیتور نشان میده در حالی که در کد اولی این مشکل ایجاد نمیشه. ایرادش چیه ؟
// read RPM
#include <SPI.h>
#include <SD.h>
// for Due/Mega/Leonardo use the hardware SPI pins (which are different)
#define _sclk 13
#define _miso 12
#define _mosi 11
const int chipSelect = 4; //number of pin cs of sd-card
// read RPM

int half_revolutions = 0;


int rpm = 0;


unsigned long lastmillis = 0;


void setup(){
Serial.begin(9600);
attachInterrupt(0, rpm_fan, FALLING);

if (!SD.begin(chipSelect)) {
Serial.println("Card failed, or not present");
// don't do anything more:
return;}
Serial.println("card initialized.");
SD.remove("datalog.txt");
File dataFile = SD.open("datalog.txt", FILE_WRITE);
dataFile.print("بسمه تعالی ");dataFile.print("\n");
dataFile.print("RPM \tFrequence\n");
dataFile.print("-------\t\t--------------\n");
dataFile.close();
}


void loop(){


if (millis() - lastmillis == 1000){ //Uptade every one second, this will be equal to reading frecuency (Hz).

detachInterrupt(0);//Disable interrupt when calculating

rpm = half_revolutions * 60; // Convert frecuency to RPM, note: this works for one interruption per full rotation. For two interrups per full rotation use half_revolutions * 30.


Serial.print("RPM =\t"); //print the word "RPM" and tab.
Serial.print(rpm); // print the rpm value.
Serial.print("\t Hz=\t"); //print the word "Hz".
Serial.println(half_revolutions); //print revolutions per second or Hz. And print new line or enter.

File dataFile = SD.open("datalog.txt", FILE_WRITE);
if (dataFile) { // if the file is available, write to it:
dataFile.print(rpm);dataFile.print("\t");dataFile. print(half_revolutions);
dataFile.print("\n");
dataFile.close();
}
else { // if the file isn't open, pop up an error:
Serial.println("error opening datalog.txt");
}

half_revolutions = 0; // Restart the RPM counter
lastmillis = millis(); // Uptade lasmillis
attachInterrupt(0, rpm_fan, FALLING); //enable interrupt
}
}


// this code will be executed every time the interrupt 0 (pin2) gets low.


void rpm_fan(){
half_revolutions++;
}