Sim800L.cpp

/*
 *  This library was written by Vittorio Esposito
 *    https://github.com/VittorioEsposito
 *
 *  Designed to work with the GSM Sim800L.
 *
 *  ENG
 *  	This library uses SoftwareSerial, you can define RX and TX pins
 *  	in the header "Sim800L.h", by default pins are RX=10 and TX=11.
 *  	Be sure that GND is connected to arduino too.
 *  	You can also change the RESET_PIN as you prefer.
 *
 *   DEFAULT PINOUT:
 *        _____________________________
 *       |  ARDUINO UNO >>>   Sim800L  |
 *        -----------------------------
 *            GND      >>>   GND
 *        RX  10       >>>   TX
 *        TX  11       >>>   RX
 *       RESET 2       >>>   RST
 *
 *   POWER SOURCE 4.2V >>> VCC
 *
 *
 *	SOFTWARE SERIAL NOTES:
 *
 *		PINOUT
 *		The library has the following known limitations:
 *		1. If using multiple software serial ports, only one can receive data at a time.
 *		2. Not all pins on the Mega and Mega 2560 support change interrupts, so only the following can be used for RX: 10, 11, 12, 13, 14, 15, 50, 51, 52, 53, A8 (62), A9 (63), A10 (64), A11 (65), A12 (66), A13 (67), A14 (68), A15 (69).
 *		3. Not all pins on the Leonardo and Micro support change interrupts, so only the following can be used for RX: 8, 9, 10, 11, 14 (MISO), 15 (SCK), 16 (MOSI).
 *		4. On Arduino or Genuino 101 the current maximum RX speed is 57600bps
 *		5. On Arduino or Genuino 101 RX doesn't work on Pin 13
 *
 *		BAUD RATE
 *		Supported baud rates are 300, 600, 1200, 2400, 4800, 9600, 14400, 19200, 28800, 31250, 38400, 57600, and 115200.
 *
 *
 *	Edited on:  December 24, 2016
 *    Editor:   Vittorio Esposito
 *
 *  Original version by:   Cristian Steib
 *
 *
*/

#include "Arduino.h"
#include "Sim800L.h"
#include <SoftwareSerial.h>

//SoftwareSerial SIM(RX_PIN,TX_PIN);
//String _buffer;

Sim800L::Sim800L(void) : SoftwareSerial(DEFAULT_RX_PIN, DEFAULT_TX_PIN)
{
    RX_PIN 		= DEFAULT_RX_PIN;
    TX_PIN 		= DEFAULT_TX_PIN;
    RESET_PIN 	= DEFAULT_RESET_PIN;
    LED_PIN 	= DEFAULT_LED_PIN;
    LED_FLAG 	= DEFAULT_LED_FLAG;
}

Sim800L::Sim800L(uint8_t rx, uint8_t tx) : SoftwareSerial(rx, tx)
{
    RX_PIN 		= rx;
    TX_PIN 		= tx;
    RESET_PIN 	= DEFAULT_RESET_PIN;
    LED_PIN 	= DEFAULT_LED_PIN;
    LED_FLAG 	= DEFAULT_LED_FLAG;
}

Sim800L::Sim800L(uint8_t rx, uint8_t tx, uint8_t rst) : SoftwareSerial(rx, tx)
{
    RX_PIN 		= rx;
    TX_PIN 		= tx;
    RESET_PIN 	= rst;
    LED_PIN 	= DEFAULT_LED_PIN;
    LED_FLAG 	= DEFAULT_LED_FLAG;
}

Sim800L::Sim800L(uint8_t rx, uint8_t tx, uint8_t rst, uint8_t led) : SoftwareSerial(rx, tx)
{
    RX_PIN 		= rx;
    TX_PIN 		= tx;
    RESET_PIN 	= rst;
    LED_PIN 	= led;
    LED_FLAG 	= true;
}

void Sim800L::begin()
{

    isBusy = false;
    pinMode(RESET_PIN, OUTPUT);

    _baud = DEFAULT_BAUD_RATE;			// Default baud rate 9600
    this->SoftwareSerial::begin(_baud);

    _sleepMode = 0;
    _functionalityMode = 1;

    if (LED_FLAG) pinMode(LED_PIN, OUTPUT);

    _buffer.reserve(BUFFER_RESERVE_MEMORY); // Reserve memory to prevent intern fragmention
}

void Sim800L::begin(uint32_t baud)
{

    pinMode(RESET_PIN, OUTPUT);

    _baud = baud;
    this->SoftwareSerial::begin(_baud);

    _sleepMode = 0;
    _functionalityMode = 1;

    if (LED_FLAG) pinMode(LED_PIN, OUTPUT);

    _buffer.reserve(BUFFER_RESERVE_MEMORY); // Reserve memory to prevent intern fragmention
}


/*
 * AT+CSCLK=0	Disable slow clock, module will not enter sleep mode.
 * AT+CSCLK=1	Enable slow clock, it is controlled by DTR. When DTR is high, module can enter sleep mode. When DTR changes to low level, module can quit sleep mode
 */
bool Sim800L::setSleepMode(bool state)
{

    _sleepMode = state;

    if (_sleepMode) this->SoftwareSerial::print(F("AT+CSCLK=1\r\n "));
    else 			this->SoftwareSerial::print(F("AT+CSCLK=0\r\n "));

    if ( (_readSerial().indexOf("ER")) == -1)
    {
        return false;
    }
    else return true;
    // Error found, return 1
    // Error NOT found, return 0
}

bool Sim800L::getSleepMode()
{
    return _sleepMode;
}

/*
 * AT+CFUN=0	Minimum functionality
 * AT+CFUN=1	Full functionality (defualt)
 * AT+CFUN=4	Flight mode (disable RF function)
*/
bool Sim800L::setFunctionalityMode(uint8_t fun)
{

    if (fun==0 || fun==1 || fun==4)
    {

        _functionalityMode = fun;

        switch(_functionalityMode)
        {
        case 0:
            this->SoftwareSerial::print(F("AT+CFUN=0\r\n "));
            break;
        case 1:
            this->SoftwareSerial::print(F("AT+CFUN=1\r\n "));
            break;
        case 4:
            this->SoftwareSerial::print(F("AT+CFUN=4\r\n "));
            break;
        }

        if ( (_readSerial().indexOf("ER")) == -1)
        {
            return false;
        }
        else return true;
        // Error found, return 1
        // Error NOT found, return 0
    }
    return false;
}

uint8_t Sim800L::getFunctionalityMode()
{
    return _functionalityMode;
}

bool Sim800L::setPIN(String pin)
{
    String command;
    command  = "AT+CPIN=";
    command += pin;
    command += "\r";

    // Can take up to 5 seconds

    this->SoftwareSerial::print(command);

    String pinStatus = "";

    int indexOfAnswer = -1;
    while (indexOfAnswer == -1)
    {
        pinStatus = _readSerial(10000);
        if(pinStatus.indexOf("ERR") != -1)
        {
            Serial.println(pinStatus);
            return false;
        }
        if(pinStatus.indexOf("OK") != -1)
        {
            Serial.println(pinStatus);
            return true;
        }
    }


    // Error found, return 1
    // Error NOT found, return 0
}

bool Sim800L::PINIsReady()
{
    String command;
    command  = "AT+CPIN?";
    command += "\r";

    // Can take up to 5 seconds

    this->SoftwareSerial::print(command);
    
    int indexOfAnswer = -1;
    String pinStatus = ""; 
    while (indexOfAnswer == -1)
    {
        pinStatus = _readSerial(10000);
        indexOfAnswer = pinStatus.indexOf("ERR");
        if(indexOfAnswer == -1)
        {
            indexOfAnswer = pinStatus.indexOf("OK");
        }
    }
    
    if ( pinStatus.indexOf("CPIN: READY") != -1)
    {
         return true;
    }

    return false;
}

bool Sim800L::disablePin(String pin)
{
    
    if(setPIN(pin))
    {
        String command;
        command  = "AT+CLCK=\"SC\",0,\""+pin+"\"";
        command += "\r";

        // Can take up to 5 seconds

        this->SoftwareSerial::print(command);

        String pinStatus = _readSerial(10000);

        Serial.println(pinStatus);
        if(pinStatus.indexOf("OK") != -1)
        {
            return true;
        }

    }
   
    return false;

}

String Sim800L::getProductInfo()
{
    this->SoftwareSerial::print("ATI\r");
    return (_readSerial());
}


String Sim800L::getOperatorsList()
{

    // Can take up to 45 seconds

    this->SoftwareSerial::print("AT+COPS=?\r");

    return _readSerial(45000);

}

String Sim800L::getOperator()
{

    this->SoftwareSerial::print("AT+COPS ?\r");

    String operatorName = _readSerial(1500);

    if ((operatorName.indexOf("+COPS:")) == -1)
    {
        return "Unknown";
    }

    if ((operatorName.indexOf("\"")) != -1)
    {
        int indexOfQuote = operatorName.indexOf("\"");
        int lastIndexOfQuote = operatorName.lastIndexOf("\"");

        if(lastIndexOfQuote != indexOfQuote && indexOfQuote < lastIndexOfQuote)
        {
            return operatorName.substring(indexOfQuote+1, lastIndexOfQuote);
        }

    }

    return _readSerial();

}

bool Sim800L::registerToNetwork()
{
    this->SoftwareSerial::print("AT+CREG=1\r");

    if ( (_readSerial(5000).indexOf("OK")) == -1)
    {
        return true;
    }

    return false;
}

NetworkRegistrationStatus Sim800L::registrationStatus()
{
    this->SoftwareSerial::print("AT+CREG ?\r");

    String status = _readSerial(); 
    
   if(status.indexOf("CREG: 0,1") > -1)
    {
        return NetworkRegistrationStatus::notRegistrerAndNotSearching;
    }
    if(status.indexOf("CREG: 1,1") > -1)
    {
        return NetworkRegistrationStatus::registrerHomeNetwork;
    }
    if(status.indexOf("CREG: 2,1") > -1)
    {
        return NetworkRegistrationStatus::notRegistrerAndSearching;
    }
    if(status.indexOf("CREG: 3,1") > -1)
    {
        return NetworkRegistrationStatus::registerDenied;
    }
    if(status.indexOf("CREG: 4,1") > -1)
    {
        return NetworkRegistrationStatus::unknown;
    }
    if(status.indexOf("CREG: 5,1") > -1)
    {
        return NetworkRegistrationStatus::registerRoaming;
    }
    if(status.indexOf("CREG: 6,1") > -1)
    {
        return NetworkRegistrationStatus::registerSmsOnlyHomeNetwork;
    }
    if(status.indexOf("CREG: 7,1") > -1)
    {
        return NetworkRegistrationStatus::registerSmsOnlyRoaming;
    }
    if(status.indexOf("CREG: 8,1") > -1)
    {
        return NetworkRegistrationStatus::registeredForEmergencyService;
    }
    if(status.indexOf("CREG: 9,1") > -1)
    {
        return NetworkRegistrationStatus::registeredForCSFBNotPreferedHomeNetwork;
    }
    if(status.indexOf("CREG: 9,1") > -1)
    {
        return NetworkRegistrationStatus::registeredForCSFBNotPreferedRoaming;
    }

    return NetworkRegistrationStatus::unknown;
}


bool Sim800L::calculateLocation()
{
    /*
    	Type: 1  To get longitude and latitude
    	Cid = 1  Bearer profile identifier refer to AT+SAPBR
    */

    uint8_t type = 1;
    uint8_t cid = 1;
	
	String tmp = "AT+CIPGSMLOC=" + String(type) + "," + String(cid) + "\r\n";
	this->SoftwareSerial::print(tmp);
	
	/*
    this->SoftwareSerial::print("AT+CIPGSMLOC=");
    this->SoftwareSerial::print(type);
    this->SoftwareSerial::print(",");
    this->SoftwareSerial::print(cid);
    this->SoftwareSerial::print("\r");
	*/

    String data = _readSerial(20000);

    if (data.indexOf("ER")!=(-1)) return false;

    uint8_t indexOne;
    uint8_t indexTwo;

    indexOne = data.indexOf(":") + 1;
    indexTwo = data.indexOf(",");

    _locationCode = data.substring(indexOne, indexTwo);

    indexOne = data.indexOf(",") + 1;
    indexTwo = data.indexOf(",", indexOne);

    _longitude = data.substring(indexOne, indexTwo);

    indexOne = data.indexOf(",", indexTwo) + 1;
    indexTwo = data.indexOf(",", indexOne);

    _latitude = data.substring(indexOne, indexTwo);

    return true;

}

String Sim800L::getLocationCode()
{
    return _locationCode;
    /*
     Location Code:
     0      Success
     404    Not Found
     408    Request Time-out
     601    Network Error
     602    No Memory
     603    DNS Error
     604    Stack Busy
     65535  Other Error
    */
}

String Sim800L::getLongitude()
{
    return _longitude;
}

String Sim800L::getLatitude()
{
    return _latitude;
}


//
//PUBLIC METHODS
//

void Sim800L::reset()
{
    if (LED_FLAG) digitalWrite(LED_PIN,1);

    digitalWrite(RESET_PIN,1);
    delay(1000);
    digitalWrite(RESET_PIN,0);
    delay(1000);
    // wait for the module response

    this->SoftwareSerial::print(F("AT\r\n"));
    while (_readSerial().indexOf("OK")==-1 )
    {
        this->SoftwareSerial::print(F("AT\r\n"));
    }

    //wait for sms ready
    while (_readSerial().indexOf("SMS")==-1 );

    if (LED_FLAG) digitalWrite(LED_PIN,0);

}

void Sim800L::setPhoneFunctionality()
{
    /*AT+CFUN=<fun>[,<rst>]
    Parameters
    <fun> 0 Minimum functionality
    1 Full functionality (Default)
    4 Disable phone both transmit and receive RF circuits.
    <rst> 1 Reset the MT before setting it to <fun> power level.
    */
    this->SoftwareSerial::print (F("AT+CFUN=1\r\n"));
}


String Sim800L::signalQuality()
{
    /*Response
    +CSQ: <rssi>,<ber>Parameters
    <rssi>
    0 -115 dBm or less
    1 -111 dBm
    2...30 -110... -54 dBm
    31 -52 dBm or greater
    99 not known or not detectable
    <ber> (in percent):
    0...7 As RXQUAL values in the table in GSM 05.08 [20]
    subclause 7.2.4
    99 Not known or not detectable
    */
    this->SoftwareSerial::print (F("AT+CSQ\r\n"));
    return(_readSerial());
}


void Sim800L::activateBearerProfile()
{
    this->SoftwareSerial::print (F(" AT+SAPBR=3,1,\"CONTYPE\",\"GPRS\" \r\n" ));
    _buffer=_readSerial();  // set bearer parameter
    this->SoftwareSerial::print (F(" AT+SAPBR=3,1,\"APN\",\"internet\" \r\n" ));
    _buffer=_readSerial();  // set apn
    this->SoftwareSerial::print (F(" AT+SAPBR=1,1 \r\n"));
    delay(1200);
    _buffer=_readSerial();			// activate bearer context
    this->SoftwareSerial::print (F(" AT+SAPBR=2,1\r\n "));
    delay(3000);
    _buffer=_readSerial(); 			// get context ip address
}


void Sim800L::deactivateBearerProfile()
{
    this->SoftwareSerial::print (F("AT+SAPBR=0,1\r\n "));
    delay(1500);
}



bool Sim800L::answerCall()
{
    this->SoftwareSerial::print (F("ATA\r\n"));
    //Response in case of data call, if successfully connected
    if ( (_readSerial().indexOf("ER")) == -1)
    {
        return false;
    }
    else return true;
    // Error found, return 1
    // Error NOT found, return 0
}


void  Sim800L::callNumber(char* number)
{
    this->SoftwareSerial::print (F("ATD"));
    this->SoftwareSerial::print (number);
    this->SoftwareSerial::print (F(";\r\n"));
}



uint8_t Sim800L::getCallStatus()
{
    /*
      values of return:

     0 Ready (MT allows commands from TA/TE)
     2 Unknown (MT is not guaranteed to respond to tructions)
     3 Ringing (MT is ready for commands from TA/TE, but the ringer is active)
     4 Call in progress

    */
    this->SoftwareSerial::print (F("AT+CPAS\r\n"));
    _buffer=_readSerial();
    return _buffer.substring(_buffer.indexOf("+CPAS: ")+7,_buffer.indexOf("+CPAS: ")+9).toInt();

}



bool Sim800L::hangoffCall()
{
    this->SoftwareSerial::print (F("ATH\r\n"));
    _buffer=_readSerial();
    if ( (_buffer.indexOf("ER")) == -1)
    {
        return false;
    }
    else return true;
    // Error found, return 1
    // Error NOT found, return 0
}

int Sim800L::sendSms(String pdu)
{
    int pduLength = (pdu.length() / 2)-1;

    if(pduLength < 10 || isBusy)
    {
        // Bad Pdu
        return -4;
    }

    isBusy = true;
    this->SoftwareSerial::print (F("AT+CMGS="));  	// command to send sms
    this->SoftwareSerial::print (pduLength);
    this->SoftwareSerial::println();
    _buffer=_readSerial(100);
    this->SoftwareSerial::print (pdu);
    _buffer=_readSerial(100);
    this->SoftwareSerial::write(0x1a); // Ctrl+Z end of the message
    _buffer=_readSerial(60000);
    
    //expect CMGS:xxx   , where xxx is a number,for the sending sms.
    if ((_buffer.indexOf(F("ERROR"))) != -1) {
        isBusy = false;
        return -2;
    }
    
    if ((_buffer.indexOf(F("CMGS"))) < 0) {
        isBusy = false;
        return -3;
  	}
    
    int indexOfTwoDots = _buffer.indexOf(':');

    isBusy = false;

    if(indexOfTwoDots == -1)
    {
        return -1;
    }

    return (_buffer.substring(indexOfTwoDots+1)).toInt();

}

bool Sim800L::sendSms(char* number,char* text)
{

    // Can take up to 60 seconds

    this->SoftwareSerial::print (F("AT+CMGF=1\r")); 	//set sms to text mode
    _buffer=_readSerial();
    this->SoftwareSerial::print (F("AT+CMGS=\""));  	// command to send sms
    this->SoftwareSerial::print (number);
    this->SoftwareSerial::print(F("\"\r"));
    _buffer=_readSerial();
    this->SoftwareSerial::print (text);
    this->SoftwareSerial::print (F("\r"));
    _buffer=_readSerial();
    this->SoftwareSerial::print((char)26);
    _buffer=_readSerial(60000);
    // Serial.println(_buffer);
    //expect CMGS:xxx   , where xxx is a number,for the sending sms.
    if ((_buffer.indexOf(F("ER"))) != -1) {
        return true;
    } else if ((_buffer.indexOf(F("CMGS"))) != -1) {
        return false;
  	} else {
    	return true;
  	}
    // Error found, return 1
    // Error NOT found, return 0
}

bool Sim800L::setPduMode()
{
	this->SoftwareSerial::print(F("AT+CMGF=0\r"));
    _buffer=_readSerial();
    
    if((_buffer.indexOf(F("OK"))) == -1)
    {
        return false;
    }

    return true;
}

bool Sim800L::setTextMode()
{
	this->SoftwareSerial::print(F("AT+CMGF=1\r"));
    _buffer=_readSerial();
    Serial.print(_buffer);
    if((_buffer.indexOf(F("OK"))) == -1)
    {
        return false;
    }

    return true;
}

bool Sim800L::prepareForSmsReceive()
{
	
	this->SoftwareSerial::print(F("AT+CNMI=2,2,0,1,0\r")); // 2,1,0,1,0 Active Ds mode (Data report)
    _buffer=_readSerial();
    //Serial.print(_buffer);
    if((_buffer.indexOf(F("OK"))) == -1)
    {
        return false;
    }
    return true;
}

void Sim800L::checkForGsmMessage()
{
	 _buffer = _readSerial(100);
	 if(_buffer.length() == 0)
	 {
        return ;
	 	//return 0;
	 }
     _buffer += _readSerial(5000);
   /*  Serial.println("checkForSMS");

	 Serial.println(_buffer);
     
	 Serial.println("-----------------");*/

    int indexOfCds = _buffer.indexOf(F("+CDS:"));
    int firstIndexHandle = 0;
    int lastIndexHandle = 0;
    //bool hasMeetFirstCrlf = false;

    if(indexOfCds != -1)
    {
        // Here we receive a Status report
        // Response format
        //+CDS: 33\r\n
        //07913366003000F006090B913356108867F8122091901000401220919010004000\r\n

        for(int i = indexOfCds; i < _buffer.length(); i++)
        {
           /* if(hasMeetFirstCrlf)
            {
            // need to wait for the first CR
            Serial.print(_buffer[i]);
            Serial.print(" --- ");
            Serial.println(_buffer[i], HEX);
            }*/
         
            if(i>0 && _buffer[i-1] == '\r' && _buffer[i] == '\n')
            {
                if(firstIndexHandle == 0)
                {
                    firstIndexHandle = i+1;

                    //hasMeetFirstCrlf = true;
                }
                else{
                    lastIndexHandle = i-1;
                    // we are at the end of the line. Need to send info
                    if(firstIndexHandle > 0 && lastIndexHandle > firstIndexHandle)
                    {
                        if(onStatusReport != NULL){
                            onStatusReport(_buffer.substring(firstIndexHandle, lastIndexHandle));
                        }
                    }
                }
              
            }
        }

    }

    firstIndexHandle = 0;
    lastIndexHandle = 0;
    int indexOfCMT = _buffer.indexOf(F("+CMT:"));

    while(indexOfCMT != -1){
    // Here we receive a new message
    // Response format
    //+CMT: "",135\r\n
    //07913366003000F0240B913356108867F800001220919013734084C170381C0E87C3E170381C0E87C3E170381C0E87C3E1B05EAFD7EBF57ABD7E3E9FCFCF67341AAD56ABD56A75BD9E4AD3631ADA9FBEBC97AE3DE84974EFDE8436DFAD3872C68C62152C68C92399C29396BD964A31634AA56BD6A59CD6\r\n

        for(int i = indexOfCMT; i < _buffer.length(); i++)
        {
           
            // need to wait for the first CR
           /* Serial.print(_buffer[i]);
            Serial.print(" --- ");
            Serial.println(_buffer[i], HEX);*/
            
         
            if(i>0 && (_buffer[i-1] == '\r' && _buffer[i] == '\n') || (_buffer[i] == '\n'))
            {
                if(firstIndexHandle == 0)
                {
                    firstIndexHandle = i+1;

                    //hasMeetFirstCrlf = true;
                }
                else{

                    if(_buffer[i-1] == '\r')
                    {lastIndexHandle = i-1;}
                    else
                    {lastIndexHandle = i;}
                    // we are at the end of the line. Need to send info
                    if(firstIndexHandle > 0 && lastIndexHandle > firstIndexHandle)
                    {
                        if(onNewMessage != NULL){
                             onNewMessage(_buffer.substring(firstIndexHandle, lastIndexHandle));
                        }

                        // Check all messages in the _buffer. Indeed, we can have more than one message
                        indexOfCMT = _buffer.indexOf(F("+CMT:"), lastIndexHandle); // add the header '+CMT:' length
                        firstIndexHandle = 0;
                        
                    }
                }
              
            }
        }
    }
    
    //return _buffer;
	 // +CMTI: "SM",1
	// if(_buffer.indexOf("+CMTI:") == -1)
	// {
	// 	return 0;
	// }
	// return _buffer.substring(_buffer.indexOf(',')+1).toInt();
}

const uint8_t Sim800L::checkForSMS()
{
	 _buffer = _readSerial(100);
	 if(_buffer.length() == 0)
	 {
	 	return 0;
	 }
     _buffer += _readSerial(1000);
     
	 // +CMTI: "SM",1
	 if(_buffer.indexOf(F("+CMTI:")) == -1)
	 {
	 	return 0;
	 }
	 return _buffer.substring(_buffer.indexOf(',')+1).toInt();
}


String Sim800L::getNumberSms(uint8_t index)
{
    _buffer=readSms(index);
    //Serial.println(_buffer.length());
    if (_buffer.length() > 10) //avoid empty sms
    {
        uint8_t _idx1=_buffer.indexOf(F("+CMGR:"));
        _idx1=_buffer.indexOf("\",\"",_idx1+1);
        return _buffer.substring(_idx1+3,_buffer.indexOf("\",\"",_idx1+4));
    }
    else
    {
        return "";
    }
}

String Sim800L::readSms(uint8_t index)
{
    // Can take up to 5 seconds

    if(( _readSerial(5000).indexOf("ER")) != -1)
    {
    	return "";
    }

    this->SoftwareSerial::print (F("AT+CMGR="));
    this->SoftwareSerial::print (index);
    this->SoftwareSerial::print ("\r");
    _buffer=_readSerial();
   //Serial.println("Received !!");
   //Serial.println(_buffer);
    if (_buffer.indexOf(F("CMGR=")) == -1)
    {
    	return "";
    }

    //Serial.println(_buffer);
	_buffer = _readSerial(10000);
	byte first = _buffer.indexOf('\n', 2) + 1;
	byte second = _buffer.indexOf('\n', first);
    return _buffer.substring(first, second);
}


bool Sim800L::delAllSms()
{
    // Can take up to 25 seconds

    this->SoftwareSerial::print(F("AT+CMGD=4\r"));
    _buffer=_readSerial(25000);
    
    if ( (_buffer.indexOf(F("ER"))) == -1)
    {
        return false;
    }
    else return true;
    // Error found, return 1
    // Error NOT found, return 0
}


void Sim800L::RTCtime(int *day,int *month, int *year,int *hour,int *minute, int *second)
{
    this->SoftwareSerial::print(F("at+cclk?\r\n"));
    // if respond with ERROR try one more time.
    _buffer=_readSerial();
    if ((_buffer.indexOf(F("ERR")))!=-1)
    {
        delay(50);
        this->SoftwareSerial::print(F("at+cclk?\r\n"));
    }
    if ((_buffer.indexOf(F("ERR")))==-1)
    {
        _buffer=_buffer.substring(_buffer.indexOf("\"")+1,_buffer.lastIndexOf("\"")-1);
        *year=_buffer.substring(0,2).toInt();
        *month= _buffer.substring(3,5).toInt();
        *day=_buffer.substring(6,8).toInt();
        *hour=_buffer.substring(9,11).toInt();
        *minute=_buffer.substring(12,14).toInt();
        *second=_buffer.substring(15,17).toInt();
    }
}

//Get the time  of the base of GSM
String Sim800L::dateNet()
{
    this->SoftwareSerial::print(F("AT+CIPGSMLOC=2,1\r\n "));
    _buffer=_readSerial();

    if (_buffer.indexOf("OK")!=-1 )
    {
        return _buffer.substring(_buffer.indexOf(":")+2,(_buffer.indexOf("OK")-4));
    }
    else
        return "0";
}

// Update the RTC of the module with the date of GSM.
bool Sim800L::updateRtc(int utc)
{

    activateBearerProfile();
    _buffer=dateNet();
    deactivateBearerProfile();

    _buffer=_buffer.substring(_buffer.indexOf(",")+1,_buffer.length());
    String dt=_buffer.substring(0,_buffer.indexOf(","));
    String tm=_buffer.substring(_buffer.indexOf(",")+1,_buffer.length()) ;

    int hour = tm.substring(0,2).toInt();
    int day = dt.substring(8,10).toInt();

    hour=hour+utc;

    String tmp_hour;
    String tmp_day;
    //TODO : fix if the day is 0, this occur when day is 1 then decrement to 1,
    //       will need to check the last month what is the last day .
    if (hour<0)
    {
        hour+=24;
        day-=1;
    }
    if (hour<10)
    {

        tmp_hour="0"+String(hour);
    }
    else
    {
        tmp_hour=String(hour);
    }
    if (day<10)
    {
        tmp_day="0"+String(day);
    }
    else
    {
        tmp_day=String(day);
    }
    //for debugging
    //Serial.println("at+cclk=\""+dt.substring(2,4)+"/"+dt.substring(5,7)+"/"+tmp_day+","+tmp_hour+":"+tm.substring(3,5)+":"+tm.substring(6,8)+"-03\"\r\n");
    this->SoftwareSerial::print("at+cclk=\""+dt.substring(2,4)+"/"+dt.substring(5,7)+"/"+tmp_day+","+tmp_hour+":"+tm.substring(3,5)+":"+tm.substring(6,8)+"-03\"\r\n");
    if ( (_readSerial().indexOf("ER"))!=-1)
    {
        return true;
    }
    else return false;


}



//
//PRIVATE METHODS
//
String Sim800L::_readSerial()
{

    uint64_t timeOld = millis();

    while (!this->SoftwareSerial::available() && !(millis() > timeOld + TIME_OUT_READ_SERIAL))
    {
       // delay(13);
    }

    String str;

    while(this->SoftwareSerial::available())
    {
        if (this->SoftwareSerial::available()>0)
        {
            str += (char) this->SoftwareSerial::read();
        }
    }

    return str;

}

String Sim800L::_readSerial(uint32_t timeout)
{

    uint64_t timeOld = millis();

    while (!this->SoftwareSerial::available() && !(millis() > timeOld + timeout))
    {
        //delay(13);
    }

    String str;

    while(this->SoftwareSerial::available())
    {
        if (this->SoftwareSerial::available()>0)
        {
            str += (char) this->SoftwareSerial::read();
        }
    }

    return str;

}