Load pages from SD (W5100)

Hi, i want to do a webserver whit 5 pages, i used a example code and it works, i can enter to the main page then open other, but the problem is that after open pages for a few times it start to load slow or dont open the page, then start to work correctly again,this always happen andt i dont know if is problem whit the code or my arduino/ethernet shield, i would apreciate if someone can help me to know what happen, thanks.

Program: eth_websrv_SD_link

Description: Arduino web server that serves up a basic web
page that links to a second page. Clicking the
link will open the second page. The second page
links back to the first page.

Hardware: Arduino Uno and official Arduino Ethernet
shield. Should work with other Arduinos and
compatible Ethernet shields.
2Gb micro SD card formatted FAT16

Software: Developed using Arduino 1.0.3 software
Should be compatible with Arduino 1.0 +

Requires index.htm and page2.htm to be on the
micro SD card in the Ethernet shield micro
SD card socket.

References: - WebServer example by David A. Mellis and
modified by Tom Igoe

Date: 2 March 2013

Author: W.A. Smith, http://startingelectronics.com

#include <SPI.h>
#include <Ethernet.h>
#include <SD.h>

// MAC address from Ethernet shield sticker under board
byte mac = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress ip(10, 0, 0, 20); // IP address, may need to change depending on network
EthernetServer server(80); // create a server at port 80

File webFile;

String HTTP_req = “”; // stores the received HTTP request

void setup()
Ethernet.begin(mac, ip); // initialize Ethernet device
server.begin(); // start to listen for clients
Serial.begin(9600); // for debugging

// initialize SD card
Serial.println(“Initializing SD card…”);
if (!SD.begin(4)) {
Serial.println(“ERROR - SD card initialization failed!”);
return; // init failed
Serial.println(“SUCCESS - SD card initialized.”);
// check for index.htm file
if (!SD.exists(“index.htm”)) {
Serial.println(“ERROR - Can’t find index.htm file!”);
return; // can’t find index file
Serial.println(“SUCCESS - Found index.htm file.”);

void loop()
EthernetClient client = server.available(); // try to get client

if (client) { // got client?
boolean currentLineIsBlank = true;
while (client.connected()) {
if (client.available()) { // client data available to read
char c = client.read(); // read 1 byte (character) from client
HTTP_req += c; // save HTTP request character
Serial.print(c); // print HTTP request character to serial monitor
// last line of client request is blank and ends with \n
// respond to client only after last line received
if (c == ‘\n’ && currentLineIsBlank) {
// send a standard http response header
client.println(“HTTP/1.1 200 OK”);
client.println(“Content-Type: text/html”);
client.println(“Connnection: close”);
// send web page
if ((HTTP_req.indexOf("GET / ") > -1)
|| (HTTP_req.indexOf(“GET /index.htm”) > -1)) {
webFile = SD.open(“index.htm”); // open web page file
else if (HTTP_req.indexOf(“GET /page2.htm”) > -1) {
webFile = SD.open(“page2.htm”); // open web page file
if (webFile) {
while(webFile.available()) {
client.write(webFile.read()); // send web page to client
HTTP_req = “”; // empty the string
// every line of text received from the client ends with \r\n
if (c == ‘\n’) {
// last character on line of received text
// starting new line with next character read
currentLineIsBlank = true;
else if (c != ‘\r’) {
// a text character was received from client
currentLineIsBlank = false;
} // end if (client.available())
} // end while (client.connected())
delay(1); // give the web browser time to receive the data
client.stop(); // close the connection
} // end if (client)

You have a Ethernet, SD and String class in a Arduino Uno, that uses a lot of ram.

Is it an existing example ? Can you give a link to it ?

In the sketch, every ethernet byte is echoed to the serial monitor, which is only 9600 baud. Could you try without the "Serial.print(c);" ?

You have a Ethernet, SD and String class in a Arduino Uno, that uses a lot of ram.

Is it an existing example ? Can you give a link to it ?

In the sketch, every ethernet byte is echoed to the serial monitor, which is only 9600 baud. Could you try without the "Serial.print(c);" ?

Thanks for answer, im using a Arduino Mega 2560, and this is the link of the code Linking to Other Pages from the Arduino SD Card Web Server, i will try the code whitout the serial print and edit whit the result.

I tried removing the serial monitor and the problem still.

I don’t know what causes the slow down.
The Mega has enough ram, that should not be a problem.
Are you using the newest Arduino 1.0.4 ?
In the sketch I read 1.0.3, but you should use the newest version.
If you are using only USB power, you could try a power supply for the Mega board. Allthough a low voltage would cause other problems.

It is because of the way you are sending it. One byte per packet is very inefficient.

if (webFile) {
  while(webFile.available()) {

// Here is your holdup. You are sending one byte per packet.
// 48 bytes of header, and one byte payload.
    client.write(webFile.read()); // send web page to client

Here is another topic that covers this, and the cure.

Thanks for that.
I tried using a buffer (Arduino 1.5.2), but I still got 4kbyte per second.
Perhaps I have to try it again with that example.
zoomkat writes: "... it reduced the upload time of a 253k jpg file from 62 sec. to 15 sec.".
That is from 4kbyte per second to 16kbyte per second.

I have not tried v1.5.2 yet. Each version seems to have its own quirks. However, it seems lately we are upgrading from a lot of quirks to just a few quirks. I guess if we keep at it... :slight_smile:

My results with v1.0.4 agree with zoomkat. About 4 times as fast.

It works !
I have Arduino 1.5.2 and a Mega 2560 board with the Ethernet Shield.
I did not use the sketch by Eduort, but have my own webserver code, that started with a Adafruit example.
Data is read from the SD card and stored in a buffer of 128 byte. I write that buffer to the client.
The result is a four times higher speed. About 16 kbyte per second.