user34776: I am new to Arduino & ESP modules, here am trying to communicate with ESP-01 via Arduino UNO. I have gone through multiple websites for initial setup. But when i upload my code to UNO, ESP is not responding back.Below is the code i have used.
#include<SoftwareSerial.h>
SoftwareSerial ESP(0,1); // RX, TX
//ESP RX-->1(UNO) TX-->0(UNO)

void setup() {
// Open serial communications and wait for port to open:

    Serial.begin(9600);
    while (!Serial) {
        ; // wait for serial port to connect. Needed for native USB port only
    }

   // Serial.println("Goodnight moon!");

    // set the data rate for the SoftwareSerial port
    ESP.begin(9600);

}

void loop() {
      ESP.write("AT\r\n"); //Normally ESP responds to AT command with "OK"
    while (ESP.available()) {
        char inData = ESP.read();
        Serial.println("Got reponse from ESP8266: ");
        Serial.write(inData);
    }


}

Source: Link of the url
My observation on this is 

ESP is blinking blue light when i reset UNO
UNO TX onboard LED is blinking
when i am trying to do  Serial.println("Goodnight moon!"); it is printing
Serial.println("Got reponse from ESP8266: ");         Serial.write(inData); is not printing

My questions are:

Is there any need to flash ESP with Firmware or is it default enabled.(i have 3 esp's with me all of them not responding with above code)
If no need then what is the possible mistake i am doing.

Here is the screenshot https://i.stack.imgur.com/mOklg.png
Note: I haven't used breadboard for connection, directly connected UNO-TX -> ESP RX and UNO-RX -> ESP TX, 3.3v VCC and ground.In the above screenshot on upload nothing prints, only when i type something "Got reponse from ESP8266: " is printing

user34776: Hi all i found out the solution after a long struggle. issue was with the ch_pd as per the ESP documentation ch_pd has to be active high that means it has to get 3.3v, only then it will communicate. 
soon after that all my problems got cleared.thank you

34776: <p>I am new to Arduino &amp; ESP modules, here am trying to communicate with ESP-01 via Arduino UNO. I have gone through multiple websites for initial setup. But when i upload my code to UNO, ESP is not responding back.Below is the code i have used.</p>

<pre><code>#include&lt;SoftwareSerial.h&gt;
SoftwareSerial ESP(0,1); // RX, TX
//ESP RX--&gt;1(UNO) TX--&gt;0(UNO)

void setup() {
// Open serial communications and wait for port to open:

    Serial.begin(9600);
    while (!Serial) {
        ; // wait for serial port to connect. Needed for native USB port only
    }

   // Serial.println("Goodnight moon!");

    // set the data rate for the SoftwareSerial port
    ESP.begin(9600);

}

void loop() {
      ESP.write("AT\r\n"); //Normally ESP responds to AT command with "OK"
    while (ESP.available()) {
        char inData = ESP.read();
        Serial.println("Got reponse from ESP8266: ");
        Serial.write(inData);
    }


}
</code></pre>

<p><a href="https://arduino.stackexchange.com/questions/24807/esp8266-not-able-to-communicate-over-serial-connection-with-arduino-uno">Source: Link of the url</a></p>

<p>My observation on this is </p>

<ol>
<li>ESP is blinking blue light when i reset UNO</li>
<li>UNO TX onboard LED is blinking</li>
<li>when i am trying to do  <code>Serial.println("Goodnight moon!");</code> it is printing</li>
<li><code>Serial.println("Got reponse from ESP8266: ");         Serial.write(inData);</code> is not printing</li>
</ol>

<p>My questions are:</p>

<ol>
<li>Is there any need to flash ESP with Firmware or is it default enabled.(i have 3 esp's with me all of them not responding with above code)</li>
<li>If no need then what is the possible mistake i am doing.</li>
</ol>

<p>Here is the screenshot <a href="https://i.stack.imgur.com/mOklg.png" rel="nofollow noreferrer">https://i.stack.imgur.com/mOklg.png</a></p>

<p>Note: I haven't used breadboard for connection, directly connected UNO-TX -> ESP RX and UNO-RX -> ESP TX, 3.3v VCC and ground.In the above screenshot on upload nothing prints, only when i type something "Got reponse from ESP8266: " is printing</p>
 34776: <p>Hi all i found out the solution after a long struggle. issue was with the ch_pd as per the ESP <a href="http://ecksteinimg.de/Datasheet/Ai-thinker%20ESP-01%20EN.pdf" rel="nofollow noreferrer">documentation</a> ch_pd has to be active high that means it has to get 3.3v, only then it will communicate. </p>

<p>soon after that all my problems got cleared.thank you</p>
