ESP8266 Wi Fi Module Quick Start Guide V 1.0.4
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ESP8266 AT Command Examples
Version 0.4
Espressif Systems IOT Team
Copyright (c) 2015
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Espressif Systems
ESP8266 AT Command Examples
Disclaimer and Copyright Notice
Information in this document, including URL references, is subject to change without notice.
THIS DOCUMENT IS PROVIDED AS IS WITH NO WARRANTIES WHATSOEVER, INCLUDING ANY
WARRANTY OF MERCHANTABILITY, NON-INFRINGEMENT, FITNESS FOR ANY PARTICULAR
PURPOSE, OR ANY WARRANTY OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION
OR SAMPLE. All liability, including liability for infringement of any proprietary rights, relating to use
of information in this document is disclaimed. No licenses express or implied, by estoppel or
otherwise, to any intellectual property rights are granted herein.
The WiFi Alliance Member Logo is a trademark of the WiFi Alliance.
All trade names, trademarks and registered trademarks mentioned in this document are property of
their respective owners, and are hereby acknowledged.
Copyright © 2015 Espressif Systems Inc. All rights reserved.
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ESP8266 AT Command Examples
1. Preambles 4 ...................................................................................................
2. User Guide 4 ...................................................................................................
2.1. Single Connection as TCP Client!5"............................................................
2.2. Transparent Transmission!6"........................................................................
2.3. Multiple Connection as TCP Server!9"........................................................
2.4. UDP Transmission!11".................................................................................
1. UDP (remote IP and port are fixed) !12 .........................................................
2. UDP (remote IP, port can be changed) !13 ...................................................
3. Questions & Answers 14...............................................................................
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Table of Contents
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ESP8266 AT Command Examples
1. Preambles
Herein we introduces some specific examples on the usage of Espressif AT Commands. For more
information about the complete instruction set, please refer to Espressif AT Instruction Set
documentation.
If you have any questions about AT, please contact us: support-at@espressif.com
2. User Guide
(1) First flash in blank.bin (contains default Wi-Fi parameter settings) into the ESP8266 device,
then flash in the BIN program that supports AT commands (/esp_iot_sdk/bin/at).
(2) Power on device and set serial baud rate to 115200. Enter AT commands.
Note: Please pay attention to the new line mode, AT command need “/r/n” to be the end.
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ESP8266 AT Command Examples
2.1. Single Connection as TCP Client
•Set WiFi mode:
AT+CWMODE=3 // softAP+station mode
Response :OK
•Connect to router:
AT+CWJAP="SSID", "password" // SSID and password of router
Response :OK
•Query device’s IP:
AT+CIFSR
Response :192.168.3.106 // Device got an IP from router.
• Connect PC to the same router that ESP8266 is connected to.
Using a network tool (eg: ”NetAssist.exe”) on the computer to create a server.
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ESP8266 AT Command Examples
•ESP8266 connect to server as a client:
AT+CIPSTART="TCP", "192.168.3.116", 8080 //protocol、server IP & port
Response :OK
• Send data:
AT+CIPSEND=4 // set date length which will be sent, such as 4 bytes
>DGFY // enter the data, no CR
Response :SEND OK
Note: If the number of bytes sent is bigger than the size defined (n), will reply busy, and after
sending n number of bytes, reply SEND OK.
•Receive data:
+IPD, n: xxxxxxxxxx // received n bytes, data=xxxxxxxxxxx
2.2. Transparent Transmission
Transparent transmission is enabled only when ESP8266 is working as a single connection.
An example of how ESP8266 execute transparent transmission when it is working in station mode is
shown here. When ESP8266 is working in softAP mode, it can execute transparent transmission in
the similar way as AT commands. For more information about this, please refer to document
“ESP8266 AT Instruction Set”.
•Set WiFi mode :
AT+CWMODE=3 // softAP+station mode
Response :OK
•Connect to router:
AT+CWJAP="SSID", "password" // SSID and password of router
Response :OK
•Query device’s IP:
AT+CIFSR
Response :192.168.101.105 // Device’s IP that got from router.
• Connect PC to the same router that ESP8266 is connected to.
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ESP8266 AT Command Examples
Using a network tool (eg: ”NetAssist.exe”) on the computer to create a server.
•Device connect to server:
AT+CIPSTART="TCP", "192.168.101.110", 8080 // protocol、server IP & port
Response :OK
Linked
•Enable transparent transmission mode:
AT+CIPMODE=1
Response :OK
•Start sending data:
AT+CIPSEND
Response: > //From now on, data received from UART will be
transparent transmitted to server.
•Stop sending data:
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If a packet of data that contains only “+++”, then the transparent transmission process will be
stopped
Please be noted that if you input “+++” directly by typing, the “+++”, may not be recognised as three
consecutive “+” because of the Prolonged time when typing, therefore, it’s suggested that the
following tools shall be employed:
Input Characters: +++
New Line Mode : please don’t select the New Line Mode
Click “Send”
Note: The aim of ending “+++” is to exit transparent transmission and turn back to accept normal AT
command, while TCP still remains connected. However, we can also use command “AT+CIPSEND” to
turn back into transparent transmission.
•Delete TCP connection:
AT+CIPCLOSE
Response :CLOSED OK
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ESP8266 AT Command Examples
2.3. Multiple Connection as TCP Server
When ESP8266 is working as a TCP server, a multiple of connections shall be maintained. That is to
say, there should be more than one client connecting to ESP8266.
Here is an example showing how TCP server is realized when ESP8266 is working in softAP mode:
•Set WiFi mode :
AT+CWMODE=3 // softAP+station mode
Response :OK
• Enable multIPle connection:
AT+CIPMUX=1
Response :OK
•Setup server:
AT+CIPSERVER=1 // default port = 333
Response :OK
• After PC is connected to the softAP of the device, the PC will connect to device as a client.
Note: When ESP8266 is working as a server, there exists a timeout mechanism. That is to say, if the
client is connected to the server, whereas there is no data transmission for a period of time, then the
server will stop the connection with the client. To avoid such problems, please set up a data
transmission circulation every two seconds.
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•Send data:
// ID number of connection is defaulted to be 0.
AT+CIPSEND=0, 4 // send 4 bytes to connection NO.0
>iopd // enter the data, no CR
Response :SEND OK
Note: If the number of bytes sent is bigger than the size defined (n), will reply busy, and after
sending n number of bytes, reply SEND OK.
•Receive data:
+IPD, 0, n: xxxxxxxxxx // received n bytes, data = xxxxxxxxxx
•Delete TCP connection:
AT+CIPCLOSE=0 // Delete NO.0 connection.
Response :0, CLOSED OK
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ESP8266 AT Command Examples
2.4. UDP Transmission
UDP transmission is established via AT+CIPSTART. There is no such definition as UDP server or UDP
client. For more information about how to realize UDP transmission, please refer to document on
“ESP8266 AT Instruction Set”.
•Set WiFi mode :
AT+CWMODE=3 // softAP+station mode
Response :OK
•Connect to router:
AT+CWJAP="SSID", "password" // SSID and password of router
Response :OK
•Query device’s IP:
AT+CIFSR
Response :+CIFSR: STAIP, "192.168.101.104" // IP address of ESP8266 station
• Connect PC to the same router as ESP8266 is connected to.
Using a network tool (eg: ”NetAssist.exe”) on the computer to create a UDP .
Below is two examples on UDP transmission.
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ESP8266 AT Command Examples
1. UDP (remote IP and port are fixed)
In UDP transmission, whether remote IP and port is fixed or not is decided by the last parameter of
“AT+CIPSTART”. “0” means that the remote IP and port is fixed and cannot be changed. A specific ID
is given to such connection, making sure that the data sender and receiver will not be replaced by
other devices.
•Enable multiple connection:
AT+CIPMUX=1
Response :OK
• Create a UDP transmission, for example, ID is 4.
AT+CIPSTART=4, "UDP", "192.168.101.110", 8080, 1112, 0
Response :4, CONNECT OK
Note :
"192.168.101.110", 8080 here is the remote IP and port of UDP transmission of the opposite side,
i.e., the configuration set by PC.
1112 is the local port of ESP8266. User can self-define this port. The value of this port will be random
if it’s not defined beforehand.
0 means that the opposite terminal will not be changed though UDP transmission is established and
data is transmitted to ESP8266 UDP port 1112. For example, in this case, if another PC also creates a
UDP entity and sends data to ESP8266 port 1112. For example, ESP8266 can receive data sent from
UDP port 1112, but when data is sent using AT command “AT+CIPSEND=4, X”, it will still be sent to
the first PC end. If this parameter is not 0, it will send to a new PC.
•Send data:
AT+CIPSEND=4, 5 // Send 5 bytes to transmission NO.4
>DGFYQ // enter the data, no CR
Response :SEND OK
Note: If the number of bytes sent is bigger than the size defined (n), will reply busy, and after
sending n number of bytes, reply SEND OK.
•Receive data:
+IPD, 4, n: xxxxxxxxxx // received n bytes, data=xxxxxxxxxxx
•Delete UDP transmission NO.4:
AT+CIPCLOSE=4
Response :4, CLOSED OK
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ESP8266 AT Command Examples
2. UDP (remote IP, port can be changed)
• Create a UDP transmission, last parameter is “2”.
AT+CIPSTART="UDP", "192.168.101.110", 8080, 1112, 2
Response :CONNECT OK
Note :
"192.168.101.110", 8080 here refer to the remote IP and port of UDP transmission terminal which
is created on PC in step 4;
1112 is the local port of ESP8266. User can self-define this port. The value of this port will be random
if it’s not defined beforehand.
2 means the opposite terminal of UDP transmission side will change to be the latest one that has
been communicating with ESP8266.
•Send data:
AT+CIPSEND=5 // Send 5 bytes
>DGFYQ // enter the data, no CR
Response :SEND OK
Note: If the number of bytes sent is bigger than the size defined (n), will reply busy, and after
sending n number of bytes, reply SEND OK.
• If you want to send data to any other UDP terminals, please set the IP and port of this terminal.
AT+CIPSEND=6, ”192.168.101.111”, 1000 // Send 6 bytes
>abcdef // enter the data, no CR
Response :SEND OK
•Receive data:
+IPD, n: xxxxxxxxxx // received n bytes, data=xxxxxxxxxxx
•Delete UDP transmission:
AT+CIPCLOSE
Response :CLOSED OK
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ESP8266 AT Command Examples
3. Questions & Answers
If you have any questions about the execution of AT instructions, please contact support-
at@espressif.com. Please describe the issues that you encountered using the following format: with
information as follows:
• Version info or AT Command: You can use command “AT+GMR” to acquire your current AT
command version info.
• Hardware Module info :example AITHINK ESP-01
• Screenshot of the test steps, for example:
• If possible, please provide the printed log information, such as:
ets Jan 8 2013, rst cause: 1, boot mode: (3, 3)
load 0x40100000, len 26336, room 16
tail 0
chksum 0xde
load 0x3ffe8000, len 5672, room 8
tail 0
chksum 0x69
load 0x3ffe9630, len 8348, room 8
tail 4
chksum 0xcb
csum 0xcb
SDK version: 0.9.1
addr not ack when tx write cmd
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