ISR(TIMER1_OVF_vect){ 	sreg = SREG;

	digitalWrite(ledPin, digitalRead(ledPin)^ 1);	// invert the bit value on the ledPin 	overflowCounter++;
	TIMSK1 &= ~(1 << TOIE1);	//disable interrupt on timer1
SREG = sreg; }

// the setup routine runs once when you press reset:
void setup() {                
  // initialize the digital pin as an output.
 
  Serial.begin(115200);
  pinMode(ledPin, OUTPUT);    
  
	 	//+Serial.println("\r\nSetup...");
		//+Serial.print("\r\nInitializing the w5100 chip and open a TCP socket...");
		W5100.init(); //
		W5100.writeSnMR(s, SnMR::TCP); // set type of socket in Mode Register

		W5100.setMACAddress(smac); // set own mac address
		W5100.setIPAddress(src_ip_addr); // set own ip address
		W5100.writeSnPORT(s, src_port); // set own port (for each socket different)
		W5100.setSubnetMask(subnet_mask);
		W5100.setGatewayIp(gateway_ip);

		W5100.writeSnDHAR(s, dst_mac); // set destination mac address
		W5100.writeSnDIPR(s, dst_ip_addr); // set destination ip
		W5100.writeSnDPORT(s, dst_port); // set destination port

		W5100.writeRMSR(0x03); // RX Memory Size Register. First two bits set to 1, this corresponds to assigning all 8 kByte of RX memory for the socket 0
		W5100.writeTMSR(0x03); // TX Memory Size Register. First two bits set to 1, this corresponds to assigning all 8 kByte of TX memory for the socket 0

		W5100.writeIMR(0x01); // Interrupt Mask Register is set to enable interrupts on socket 0.

		W5100.execCmdSn(s, Sock_OPEN);
			Serial.print("\r\nDone opening socket");
			Serial.print("\r\n");

		memset(data, 0, PAYLOAD_SIZE);
		strcpy(data, "A");
		len = strlen(data);
		
		cli();
		TCCR1B = 0;
		TCCR1A = 0;
		TCNT1 = 65300;
		// prescaler
		TCCR1B |= (1 << CS10);	// Time/Counter Control Register B no prescaler needed, since we count amount of ticks
		sei();
}

// the loop routine runs over and over again forever:
void loop() {
            // wait for a second
	
		if(measurementsCounter == 1000)
		while(true){}			// endless loop after desired amount of measurements achieved

		W5100.execCmdSn(s, Sock_CONNECT);

		while ((W5100.readSnSR(s) & SnSR::ESTABLISHED) != SnSR::ESTABLISHED) { // check Status Register to find out if the connection was established

		}
		TCNT1 = 0; // reset counter. Note that the timer counts always, whether interrupt occurs decides bit in TIMSK
		TIMSK1 |= (1 << TOIE1); // enable timer overflow interrupt. Note we OR the current state of the TIMSK, so once set it is always set, if manually not changed

		while ((W5100.readSnIR(s) & SnIR::RECV) != SnIR::RECV) {}
		restTicks = TCNT1; // save rest ticks
		TIMSK1 &= ~(1 << TOIE1); // disable timer1.
		W5100.writeSnIR(s,SnIR::RECV);	// clear the interrupt bit

		time = (overflowCounter * 65535 + restTicks) * 62.5;
		measurementsCounter++;

		overflowCounter = 0;	// clear overflowCounter

		Serial.print("\r\nTerminate Connection");
		W5100.execCmdSn(s, Sock_DISCON);

		while ((W5100.readSnIR(s) & SnIR::DISCON) != SnIR::DISCON) {
		}
		W5100.writeSnIR(s,SnIR::DISCON);	// clear the interrupt bit
			Serial.print("\r\nDisconnected.");

}