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In a recent shopping spre I bought some new arduino stuff to play with.

This is the first of a few items I recentely bought from ebay: An arduino EthernetShield based on the WIZ5100 ethernet controller.

Arduino Ethernet Shield based on the WIZ5100 ethernet controller

Ever since I started thinkering with Arduino I wanted a way to connect it to a network.  So befor I got this shield I started messing around with a fonera router by connecting the rx-tx lines of the arduino to the tx-rx connections of a fonera 2100 router.  However to be able to acces the fonera via serial you need to reflash it with a third-party image (open-wrt, dd-wrt,…) . The image needs to include the tty or stty command, which enables you to set the serial communication speed of the router to a baudspeed the arduino can handle.

Arduino to Fonera Serial Communication and Duvel beer

I’ll post a guide later containing information on how to connect to a fonera router and control it wireless. The major downside of this way of connecting to a network is the usage of the RX-TX lines on the arduino board. Making it harder to debug and thus making it harder to whip something up real quick.

To be completely honnest, she wasn’t my first… .  Some time ago in a moment of weakness I was in the believe I had struck upon a genuine bargain : a (very) cheap arduino ethernet shield. As I was later to realize, the price was about right. The problem with this shield is that is uses the Microchip’s ENC28J60 SPI based ethernet controller.

"Arduino Ethernet Shield V1.1" using ENC28J60 SPI controller.

I don’t mean to bash the ENC28J60 based shield, but it shouldn’t be branded  “Arduino Ethernet Shield v1.1″ as it uses a different chip and design as stated in the reference design on the arduino website.  Because of the different chip the library you need to include differs from the arduino ethernet library. Since the library is different the code you need to write is different and in this case it could use some more abastraction.

Note : I did not buy my shield from nuelectronics but from a seller on ebay. Both shields however use the ENC28j60 chip and both are branded Arduino Ethernet Shield V1.x so my guess is in one way or the other they originated from the same place/drawingboard.

To better explain what I’m talkin about I’ll show two example programs. The first example is for the ENC28j60 based shield, the second example is for the WIZ5100 based shield using the official ethernet library.

The first code example is included in the etherShield library provided by nuelectronics

#include "etherShield.h"

// please modify the following lines. mac and ip have to be unique
// in your local area network. You can not have the same numbers in
// two devices:
static uint8_t mymac[6] = {0x54,0x55,0x58,0x10,0x00,0x24};
static uint8_t myip[4] = {192,168,1,88};
static uint16_t my_port = 1200;     // client port

// client_ip - modify it when you have multiple client on the network
// for server to distinguish each ethershield client
static char client_ip[] = "192.168.1.88";

// server settings - modify the service ip to your own server
static uint8_t dest_ip[4]={192,168,1,4};
static uint8_t dest_mac[6];

enum CLIENT_STATE
{
   IDLE, ARP_SENT, ARP_REPLY, SYNC_SENT
 };

static CLIENT_STATE client_state;

static uint8_t client_data_ready;

static uint8_t syn_ack_timeout = 0;

#define BUFFER_SIZE 500
static uint8_t buf[BUFFER_SIZE+1];

char sensorData[10];

EtherShield es=EtherShield();

// prepare the webpage by writing the data to the tcp send buffer
uint16_t print_webpage(uint8_t *buf);
int8_t analyse_cmd(char *str);
// get current temperature
#define TEMP_PIN  3
void getCurrentTemp( char *temperature);
void client_process(void);

void setup(){

   /*initialize enc28j60*/
	 es.ES_enc28j60Init(mymac);
   es.ES_enc28j60clkout(2); // change clkout from 6.25MHz to 12.5MHz
   delay(10);

	/* Magjack leds configuration, see enc28j60 datasheet, page 11 */
	// LEDA=greed LEDB=yellow
	//
	// 0x880 is PHLCON LEDB=on, LEDA=on
	// enc28j60PhyWrite(PHLCON,0b0000 1000 1000 00 00);
	es.ES_enc28j60PhyWrite(PHLCON,0x880);
	delay(500);
	//
	// 0x990 is PHLCON LEDB=off, LEDA=off
	// enc28j60PhyWrite(PHLCON,0b0000 1001 1001 00 00);
	es.ES_enc28j60PhyWrite(PHLCON,0x990);
	delay(500);
	//
	// 0x880 is PHLCON LEDB=on, LEDA=on
	// enc28j60PhyWrite(PHLCON,0b0000 1000 1000 00 00);
	es.ES_enc28j60PhyWrite(PHLCON,0x880);
	delay(500);
	//
	// 0x990 is PHLCON LEDB=off, LEDA=off
	// enc28j60PhyWrite(PHLCON,0b0000 1001 1001 00 00);
	es.ES_enc28j60PhyWrite(PHLCON,0x990);
	delay(500);
	//
  // 0x476 is PHLCON LEDA=links status, LEDB=receive/transmit
  // enc28j60PhyWrite(PHLCON,0b0000 0100 0111 01 10);
  es.ES_enc28j60PhyWrite(PHLCON,0x476);
	delay(100);

  //init the ethernet/ip layer:
  es.ES_init_ip_arp_udp_tcp(mymac,myip,80);

  // intialize varible;
  syn_ack_timeout =0;
  client_data_ready = 0;
  client_state = IDLE;
  // initialize DS18B20 datapin
    digitalWrite(TEMP_PIN, LOW);
    pinMode(TEMP_PIN, INPUT);      // sets the digital pin as input (logic 1)

}

void loop(){

        if(client_data_ready==0){
          delay(60000UL);             // delay 60s
          getCurrentTemp(sensorData);
          client_data_ready = 1;
         }
	client_process();

}

uint16_t gen_client_request(uint8_t *buf )
{
	uint16_t plen;
	byte i;

	plen= es.ES_fill_tcp_data_p(buf,0, PSTR ( "GET /ethershield_log/save.php?pwd=secret&client=" ) );
        for(i=0; client_ip[i]!='\0'; i++){
            buf[TCP_DATA_P+plen]=client_ip[i];
            plen++;
        }
        plen= es.ES_fill_tcp_data_p(buf,plen, PSTR ( "&status=temperature-" ) );
        for(i=0; sensorData[i]!='\0'; i++){

                buf[TCP_DATA_P+plen]=sensorData[i];
                plen++;
        }	

	plen= es.ES_fill_tcp_data_p(buf, plen, PSTR ( " HTTP/1.0\r\n" ));
	plen= es.ES_fill_tcp_data_p(buf, plen, PSTR ( "Host: 192.168.1.4\r\n" ));
	plen= es.ES_fill_tcp_data_p(buf, plen, PSTR ( "User-Agent: AVR ethernet\r\n" ));
        plen= es.ES_fill_tcp_data_p(buf, plen, PSTR ( "Accept: text/html\r\n" ));
	plen= es.ES_fill_tcp_data_p(buf, plen, PSTR ( "Keep-Alive: 300\r\n" ));
	plen= es.ES_fill_tcp_data_p(buf, plen, PSTR ( "Connection: keep-alive\r\n\r\n" ));

	return plen;
}

//*****************************************************************************************
//
// Function : client_process
// Description : send temparature to web server, this option is disabled by default.
// YOU MUST install webserver and server script before enable this option,
// I recommented Apache webserver and PHP script.
// More detail about Apache and PHP installation please visit http://www.avrportal.com/
//
//*****************************************************************************************
void client_process ( void )
{
    uint16_t plen;
	uint8_t i;

    if (client_data_ready == 0)  return;     // nothing to send

	if(client_state == IDLE){   // initialize ARP
       es.ES_make_arp_request(buf, dest_ip);

	   client_state = ARP_SENT;
	   return;
	}

	if(client_state == ARP_SENT){

        plen = es.ES_enc28j60PacketReceive(BUFFER_SIZE, buf);

		// destination ip address was found on network
        if ( plen!=0 )
        {
            if ( es.ES_arp_packet_is_myreply_arp ( buf ) ){
                client_state = ARP_REPLY;
				syn_ack_timeout=0;
				return;
            }

		}
	        delay(10);
		syn_ack_timeout++;

		if(syn_ack_timeout== 100) {  //timeout, server ip not found
			client_state = IDLE;
			client_data_ready =0;
			syn_ack_timeout=0;
			return;
		}
    }

 // send SYN packet to initial connection
	if(client_state == ARP_REPLY){
		// save dest mac
		for(i=0; i<6; i++){
			dest_mac[i] = buf[ETH_SRC_MAC+i];
		}

        es.ES_tcp_client_send_packet (
                       buf,
                       80,
                       1200,
                       TCP_FLAG_SYN_V,                 // flag
                       1,                                              // (bool)maximum segment size
                       1,                                              // (bool)clear sequence ack number
                       0,                                              // 0=use old seq, seqack : 1=new seq,seqack no data : new seq,seqack with data
                       0,                                              // tcp data length
		      dest_mac,
		      dest_ip
                       );

		client_state = SYNC_SENT;
	}
  // get new packet
  if(client_state == SYNC_SENT){
    plen = es.ES_enc28j60PacketReceive(BUFFER_SIZE, buf);

       // no new packet incoming
    if ( plen == 0 )
    {
        return;
    }

       // check ip packet send to avr or not?
       // accept ip packet only
    if ( es.ES_eth_type_is_ip_and_my_ip(buf,plen)==0){
		return;
    }

       // check SYNACK flag, after AVR send SYN server response by send SYNACK to AVR
    if ( buf [ TCP_FLAGS_P ] == ( TCP_FLAG_SYN_V | TCP_FLAG_ACK_V ) )
    {

               // send ACK to answer SYNACK

               es.ES_tcp_client_send_packet (
                       buf,
                       80,
                       1200,
                       TCP_FLAG_ACK_V,                 // flag
                       0,                                              // (bool)maximum segment size
                       0,                                              // (bool)clear sequence ack number
                       1,                                              // 0=use old seq, seqack : 1=new seq,seqack no data : new seq,seqack with data
                       0,                                              // tcp data length
						dest_mac,
						dest_ip
                       );
               // setup http request to server
               plen = gen_client_request( buf );
               // send http request packet
               // send packet with PSHACK
               es.ES_tcp_client_send_packet (
                                       buf,
                                       80,                                             // destination port
                                       1200,                                   // source port
                                       TCP_FLAG_ACK_V | TCP_FLAG_PUSH_V,                        // flag
                                       0,                                              // (bool)maximum segment size
                                       0,                                              // (bool)clear sequence ack number
                                       0,                                              // 0=use old seq, seqack : 1=new seq,seqack no data : >1 new seq,seqack with data
                                       plen,                           // tcp data length
                                       dest_mac,
									   dest_ip
									   );
               return;
       }
       // after AVR send http request to server, server response by send data with PSHACK to AVR
       // AVR answer by send ACK and FINACK to server
       if ( buf [ TCP_FLAGS_P ] == (TCP_FLAG_ACK_V|TCP_FLAG_PUSH_V) )
       {
               plen = es.ES_tcp_get_dlength( (uint8_t*)&buf );

               // send ACK to answer PSHACK from server
               es.ES_tcp_client_send_packet (
                                       buf,
                                       80,                                             // destination port
                                       1200,                                   // source port
                                       TCP_FLAG_ACK_V,                  // flag
                                       0,                                              // (bool)maximum segment size
                                       0,                                              // (bool)clear sequence ack number
                                       plen,                                           // 0=use old seq, seqack : 1=new seq,seqack no data : >1 new seq,seqack with data
                                       0,                              // tcp data length
				      dest_mac,
				      dest_ip
               );;
               // send finack to disconnect from web server

               es.ES_tcp_client_send_packet (
                                       buf,
                                       80,                                             // destination port
                                       1200,                                   // source port
                                       TCP_FLAG_FIN_V|TCP_FLAG_ACK_V,                  // flag
                                       0,                                              // (bool)maximum segment size
                                       0,                                              // (bool)clear sequence ack number
                                       0,                                           // 0=use old seq, seqack : 1=new seq,seqack no data : >1 new seq,seqack with data
                                       0,
										dest_mac,
										dest_ip
				);

               return;

       }
       // answer FINACK from web server by send ACK to web server
       if ( buf [ TCP_FLAGS_P ] == (TCP_FLAG_ACK_V|TCP_FLAG_FIN_V) )
       {
               // send ACK with seqack = 1
               es.ES_tcp_client_send_packet(

                                       buf,
                                       80,                                             // destination port
                                       1200,                                   // source port
                                       TCP_FLAG_ACK_V,                 // flag
                                       0,                                              // (bool)maximum segment size
                                       0,                                              // (bool)clear sequence ack number
                                       1,                                              // 0=use old seq, seqack : 1=new seq,seqack no data : >1 new seq,seqack with data
                                       0,
									   dest_mac,
									   dest_ip
				);
			client_state = IDLE;		// return to IDLE state
			client_data_ready =0;		// client data sent
		}
  }
}

void OneWireReset(int Pin) // reset.  Should improve to act as a presence pulse
{
     digitalWrite(Pin, LOW);
     pinMode(Pin, OUTPUT); // bring low for 500 us
     delayMicroseconds(500);
     pinMode(Pin, INPUT);
     delayMicroseconds(500);
}

void OneWireOutByte(int Pin, byte d) // output byte d (least sig bit first).
{
   byte n;

   for(n=8; n!=0; n--)
   {
      if ((d & 0x01) == 1)  // test least sig bit
      {
         digitalWrite(Pin, LOW);
         pinMode(Pin, OUTPUT);
         delayMicroseconds(5);
         pinMode(Pin, INPUT);
         delayMicroseconds(60);
      }
      else
      {
         digitalWrite(Pin, LOW);
         pinMode(Pin, OUTPUT);
         delayMicroseconds(60);
         pinMode(Pin, INPUT);
      }

      d=d>>1; // now the next bit is in the least sig bit position.
   }

}

byte OneWireInByte(int Pin) // read byte, least sig byte first
{
    byte d, n, b;

    for (n=0; n<8; n++)
    {
        digitalWrite(Pin, LOW);
        pinMode(Pin, OUTPUT);
        delayMicroseconds(5);
        pinMode(Pin, INPUT);
        delayMicroseconds(5);
        b = digitalRead(Pin);
        delayMicroseconds(50);
        d = (d >> 1) | (b<<7); // shift d to right and insert b in most sig bit position
    }
    return(d);
}

void getCurrentTemp(char *temp)
{
  int HighByte, LowByte, TReading, Tc_100, sign, whole, fract;

  OneWireReset(TEMP_PIN);
  OneWireOutByte(TEMP_PIN, 0xcc);
  OneWireOutByte(TEMP_PIN, 0x44); // perform temperature conversion, strong pullup for one sec

  OneWireReset(TEMP_PIN);
  OneWireOutByte(TEMP_PIN, 0xcc);
  OneWireOutByte(TEMP_PIN, 0xbe);

  LowByte = OneWireInByte(TEMP_PIN);
  HighByte = OneWireInByte(TEMP_PIN);
  TReading = (HighByte << 8) + LowByte;
  sign = TReading & 0x8000;  // test most sig bit
  if (sign) // negative
  {
    TReading = (TReading ^ 0xffff) + 1; // 2's comp
  }
  Tc_100 = (6 * TReading) + TReading / 4;    // multiply by (100 * 0.0625) or 6.25

  whole = Tc_100 / 100;  // separate off the whole and fractional portions
  fract = Tc_100 % 100;

	if(sign) temp[0]='-';
	else 		 temp[0]='+';

	temp[1]= (whole-(whole/100)*100)/10 +'0' ;
	temp[2]= whole-(whole/10)*10 +'0';

	temp[3]='.';
	temp[4]=fract/10 +'0';
	temp[5]=fract-(fract/10)*10 +'0';

	temp[6] = '\0';
}

 
As you can see this example involves alot of lowlevel configuration specific lines which could be hidden away in the library for clarity’s sake.

The second code example is one from the standard ethernet library included with any recent installation of the arduino environment. This is code that runs straight on a WIZ5100 powered ethernet shield.
 

/*
 * Web Server
 *
 * A simple web server that shows the value of the analog input pins.
 */

#include <Ethernet.h>

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
byte ip[] = { 10, 0, 0, 177 };

Server server(80);

void setup()
{
  Ethernet.begin(mac, ip);
  server.begin();
}

void loop()
{
  Client client = server.available();
  if (client) {
    // an http request ends with a blank line
    boolean current_line_is_blank = true;
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();
        // if we've gotten to the end of the line (received a newline
        // character) and the line is blank, the http request has ended,
        // so we can send a reply
        if (c == '\n' && current_line_is_blank) {
          // send a standard http response header
          client.println("HTTP/1.1 200 OK");
          client.println("Content-Type: text/html");
          client.println();

          // output the value of each analog input pin
          for (int i = 0; i < 6; i++) {
            client.print("analog input ");
            client.print(i);
            client.print(" is ");
            client.print(analogRead(i));
            client.println("<br />");
          }
          break;
        }
        if (c == '\n') {
          // we're starting a new line
          current_line_is_blank = true;
        } else if (c != '\r') {
          // we've gotten a character on the current line
          current_line_is_blank = false;
        }
      }
    }
    // give the web browser time to receive the data
    delay(1);
    client.stop();
  }
}

 
Needless to say the latter is easier for the eye ( of mind ). Right now I use the WIZ5100 based shield for quick prototyping of new ideas and the ENC28j60 shield is used for more permanent setups, as the code isn’t stuff I want to rewrite on a daily basis.

Next up will be some more things I picked up :

• an rf-transmitter-receiver pair

• a PIR-sensor

• an Arduino sensor-shield

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