Hello,
Here you are. Illustration of “strange behaviour” using “the very big text” in serverDemo() function below.
The Code:
/************************************************************
ESP8266_Shield_Demo.h
SparkFun ESP8266 AT library - Demo
Jim Lindblom @ SparkFun Electronics
Original Creation Date: July 16, 2015
https://github.com/sparkfun/SparkFun_ESP8266_AT_Arduino_Library
This example demonstrates the basics of the SparkFun ESP8266
AT library. It'll show you how to connect to a WiFi network,
get an IP address, connect over TCP to a server (as a client),
and set up a TCP server of our own.
Development environment specifics:
IDE: Arduino 1.6.5
Hardware Platform: Arduino Uno
ESP8266 WiFi Shield Version: 1.0
This code is released under the MIT license.
Distributed as-is; no warranty is given.
************************************************************/
//////////////////////
// Library Includes //
//////////////////////
// SoftwareSerial is required (even you don't intend on
// using it).
#include <SoftwareSerial.h>
#include <SparkFunESP8266WiFi.h>
#include <Time.h>
//////////////////////////////
// WiFi Network Definitions //
//////////////////////////////
// Replace these two character strings with the name and
// password of your WiFi network.
const char mySSID[] = "<my_SSID>";
const char myPSK[] = "<my_PSK>";
//////////////////////////////
// ESP8266Server definition //
//////////////////////////////
// server object used towards the end of the demo.
// (This is only global because it's called in both setup()
// and loop()).
ESP8266Server server = ESP8266Server(80);
//////////////////
// HTTP Strings //
//////////////////
const char destServer[] = "example.com";
const String htmlHeader = "HTTP/1.1 200 OK\r\n"
"Content-Type: text/html\r\n"
"Connection: close\r\n\r\n"
"<!DOCTYPE HTML>\r\n"
"<html><head><meta http-equiv=\"refresh\" content=\"4\"></head>\r\n";
const String httpRequest = "GET / HTTP/1.1\n"
"Host: example.com\n"
"Connection: close\n\n";
// All functions called from setup() are defined below the
// loop() function. They modularized to make it easier to
// copy/paste into sketches of your own.
void setup()
{
// Serial Monitor is used to control the demo and view
// debug information.
Serial.begin(9600);
serialTrigger(F("Press any key to begin."));
// initializeESP8266() verifies communication with the WiFi
// shield, and sets it up.
initializeESP8266();
// connectESP8266() connects to the defined WiFi network.
connectESP8266();
// displayConnectInfo prints the Shield's local IP
// and the network it's connected to.
displayConnectInfo();
// serialTrigger(F("Press any key to connect client."));
// clientDemo();
unsigned long pctime;
Serial.println();
Serial.println("Enter current time (seconds passed since Jan 1 1970)");
Serial.println();
while (!Serial.available())
;
pctime = Serial.parseInt();
setTime(pctime);
digitalClockDisplay();
//serialTrigger(F("Press any key to test server."));
serverSetup();
}
void loop()
{
serverDemo();
}
void initializeESP8266()
{
// esp8266.begin() verifies that the ESP8266 is operational
// and sets it up for the rest of the sketch.
// It returns either true or false -- indicating whether
// communication was successul or not.
// true
int test = esp8266.begin();
if (test != true)
{
Serial.println(F("Error talking to ESP8266."));
errorLoop(test);
}
Serial.println(F("ESP8266 Shield Present"));
}
void connectESP8266()
{
// The ESP8266 can be set to one of three modes:
// 1 - ESP8266_MODE_STA - Station only
// 2 - ESP8266_MODE_AP - Access point only
// 3 - ESP8266_MODE_STAAP - Station/AP combo
// Use esp8266.getMode() to check which mode it's in:
int retVal = esp8266.getMode();
if (retVal != ESP8266_MODE_STA)
{ // If it's not in station mode.
// Use esp8266.setMode([mode]) to set it to a specified
// mode.
retVal = esp8266.setMode(ESP8266_MODE_STA);
if (retVal < 0)
{
Serial.println(F("Error setting mode."));
errorLoop(retVal);
}
}
Serial.println(F("Mode set to station"));
// esp8266.status() indicates the ESP8266's WiFi connect
// status.
// A return value of 1 indicates the device is already
// connected. 0 indicates disconnected. (Negative values
// equate to communication errors.)
retVal = esp8266.status();
if (retVal <= 0)
{
Serial.print(F("Connecting to "));
Serial.println(mySSID);
// esp8266.connect([ssid], [psk]) connects the ESP8266
// to a network.
// On success the connect function returns a value >0
// On fail, the function will either return:
// -1: TIMEOUT - The library has a set 30s timeout
// -3: FAIL - Couldn't connect to network.
retVal = esp8266.connect(mySSID, myPSK);
if (retVal < 0)
{
Serial.println(F("Error connecting"));
errorLoop(retVal);
}
}
}
void displayConnectInfo()
{
char connectedSSID[24];
memset(connectedSSID, 0, 24);
// esp8266.getAP() can be used to check which AP the
// ESP8266 is connected to. It returns an error code.
// The connected AP is returned by reference as a parameter.
int retVal = esp8266.getAP(connectedSSID);
if (retVal > 0)
{
Serial.print(F("Connected to: "));
Serial.println(connectedSSID);
}
// esp8266.localIP returns an IPAddress variable with the
// ESP8266's current local IP address.
IPAddress myIP = esp8266.localIP();
Serial.print(F("My IP: ")); Serial.println(myIP);
}
void clientDemo()
{
// To use the ESP8266 as a TCP client, use the
// ESP8266Client class. First, create an object:
ESP8266Client client;
// ESP8266Client connect([server], [port]) is used to
// connect to a server (const char * or IPAddress) on
// a specified port.
// Returns: 1 on success, 2 on already connected,
// negative on fail (-1=TIMEOUT, -3=FAIL).
int retVal = client.connect(destServer, 80);
if (retVal <= 0)
{
Serial.println(F("Failed to connect to server."));
return;
}
// print and write can be used to send data to a connected
// client connection.
client.print(httpRequest);
// available() will return the number of characters
// currently in the receive buffer.
while (client.available())
Serial.write(client.read()); // read() gets the FIFO char
// connected() is a boolean return value - 1 if the
// connection is active, 0 if it's closed.
if (client.connected())
client.stop(); // stop() closes a TCP connection.
}
void serverSetup()
{
// begin initializes a ESP8266Server object. It will
// start a server on the port specified in the object's
// constructor (in global area)
server.begin();
Serial.print(F("Server started! Go to "));
Serial.println(esp8266.localIP());
Serial.println();
}
void serverDemo()
{
// available() is an ESP8266Server function which will
// return an ESP8266Client object for printing and reading.
// available() has one parameter -- a timeout value. This
// is the number of milliseconds the function waits,
// checking for a connection.
ESP8266Client client = server.available(700);
if (client)
{
Serial.println(F("Client Connected!"));
// an http request ends with a blank line
boolean currentLineIsBlank = true;
while (client.connected())
{
if (client.available())
{
char c = client.read();
// if you've gotten to the end of the line (received a newline
// character) and the line is blank, the http request has ended,
// so you can send a reply
if (c == '\n' && currentLineIsBlank)
{
Serial.println(F("Sending HTML page"));
// send a standard http response header:
client.print(htmlHeader);
String htmlBody;
htmlBody += "Just some big text. This is very big text in front.";
htmlBody += "
\n";
htmlBody += "LTQ: "; //Just some labels for future use
htmlBody += "
\n";
htmlBody += "LTM: ";
htmlBody += "
\n";
htmlBody += "LTL: ";
htmlBody += "
\n";
// output the value of each analog input pin
for (int a = 0; a < 6; a++)
{
htmlBody += "A";
htmlBody += String(a);
htmlBody += ": ";
htmlBody += String(analogRead(a));
htmlBody += "
\n";
}
htmlBody += "<hr>\n";
htmlBody += "
\n";
htmlBody += "CT: ";
//htmlBody += String(now()); //Yes, this line is just commented out for the moment.
htmlBody += "</html>\n";
Serial.print(htmlBody);
client.print(htmlBody);
break;
}
if (c == '\n')
{
// you're starting a new line
currentLineIsBlank = true;
}
else if (c != '\r')
{
// you've gotten a character on the current line
currentLineIsBlank = false;
}
}
}
// give the web browser time to receive the data
delay(20);
// close the connection:
client.stop();
Serial.println(F("Client disconnected"));
}
}
// errorLoop prints an error code, then loops forever.
void errorLoop(int error)
{
Serial.print(F("Error: ")); Serial.println(error);
Serial.println(F("Looping forever."));
for (;;)
;
}
// serialTrigger prints a message, then waits for something
// to come in from the serial port.
void serialTrigger(String message)
{
Serial.println();
Serial.println(message);
Serial.println();
while (!Serial.available())
;
while (Serial.available())
Serial.read();
}
void digitalClockDisplay(){
// digital clock display of the time
Serial.print(hour());
printDigits(minute());
printDigits(second());
Serial.print(" ");
Serial.print(day());
Serial.print(" ");
Serial.print(month());
Serial.print(" ");
Serial.print(year());
Serial.println();
}
void printDigits(int digits){
// utility function for digital clock display: prints preceding colon and leading 0
Serial.print(":");
if(digits < 10)
Serial.print('0');
Serial.print(digits);
}
Output of The Code on Serial Monitor (Please note what happens to As. First “A0: value” and then… “A:”):
Client Connected!
Sending HTML page
Just some big text. This is very big text in front.
LTQ:
LTM:
LTL:
A0: 8
A:
A:
A:
A:
A:
<hr>
CT: </html>
Client disconnected
If I comment out in the code following line (the big text):
htmlBody += "Just some big text. This is very big text in front.";
Then, the resulting web page displays as it should (note “An: value”):
Client Connected!
Sending HTML page
LTQ:
LTM:
LTL:
A0: 7
A1: 567
A2: 470
A3: 410
A4: 348
A5: 295
<hr>
CT: </html>
Client disconnected
So in fact the Time library seems to have nothing to do here. The “strange behaviour” starts if to add “big text”: A1-A5 label indexes and values are not “generated” in the for loop in the servoDemo() function.
What could be the reason?
Thank you.
