#include <SD.h> //vlozeni knihovny

const int chipSelect = 4; //vyber pinu pro SD.begin()

void setup(){
	Serial.begin(9600);
	while (!Serial) {
		; //pocka na zahajeni komunikace - pouze pro desky s AT32u4
	}

	Serial.print("Initializing SD card...");
	pinMode(10, OUTPUT); //SS pin desky, se kterou pracujeme

	//je karta pritomna a v poradku?
	if (!SD.begin(chipSelect)) {
		Serial.println("Card failed, or not present");
		return;
	}
	Serial.println("card initialized.");
}

void loop(){
	//vytvori retezec pro shromazdovani dat
	String dataString = "";

	//precti 3 vstupy a vysledek zapis do retezce
	for (int analogPin = 0; analogPin < 3; analogPin++) {
		int sensor = analogRead(analogPin);
		dataString += String(sensor);
		if (analogPin < 2) {
			dataString += ","; 
		}
	}

	//otevre soubor
	File dataFile = SD.open("datalog.txt", FILE_WRITE);

	// pokud se otevreni povedlo, data se zapisi do slozky
	if (dataFile) {
		dataFile.println(dataString);
		dataFile.close();
		Serial.println(dataString);
	}  
	else {
		Serial.println("error opening datalog.txt");
	} 
}