ESP8266 - AT Command Reference

ESP8266, in it’s default configuration, boots up into the serial modem mode. In this mode you can communicate with it using a set of AT commands. I will present to you a reference of all known AT commands that ESP8266 supports, explain what they do and how to use them.

Historically AT commands are based on the Hayes Command Set and these are no different.

AT Commands

Index of all known AT commands

Basic WiFI layer TCPIP Layer
AT AT+CWMODE AT+CIPSTATUS
AT+RST AT+CWJAP AT+CIPSTART
AT+GMR AT+CWLAP AT+CIPSEND
AT+GSLP AT+CWQAP AT+CIPCLOSE
ATE AT+CWSAP AT+CIFSR
  AT+CWLIF AT+CIPMUX
  AT+CWDHCP AT+CIPSERVER
  AT+CIPSTAMAC AT+CIPMODE
  AT+CIPAPMAC AT+CIPSTO
  AT+CIPSTA AT+CIUPDATE
  AT+CIPAP +IPD

Line termination

ESP8266 expects <CR><LF> or CarriageReturn and LineFeed at the end of each command, but just<CR> seems to work too.

Command variants

Each command can have up to 4 variants changing the function of it. You can chose between them by appending one of four possible values to the end of the root command itself. These four appendices can have the following values "",=<parameter|[parameters]>,"?",=?

Type Example Description
Test AT+CIPSTART=? Query the range of values (So far only AT+CWMODE=? uses it)
Query AT+CMD? Returns the current value of the parameter.
Set AT+CMD=Parameter Set the value of user-defined parameters in commands and run.
Execute AT+CMD Runs commands with no user-defined parameters.
Note:

Commands

AT - Test AT startup

Variant Command Response Function
Execute AT OK Test if AT system works correctly

Back to Index

AT+RST - Restart module

Variant Command Response Function
Execute AT+RST OK Reset the module

ESP-01 Output after reset:

 ets Jan  8 2013,rst cause:4, boot mode:(3,7)

wdt reset
load 0x40100000, len 24444, room 16
tail 12
chksum 0xe0
ho 0 tail 12 room 4
load 0x3ffe8000, len 3168, room 12
tail 4
chksum 0x93
load 0x3ffe8c60, len 4956, room 4
tail 8
chksum 0xbd
csum 0xbd

ready

ESP-12 Output after reset:

\0x04B1\0x85 \0xff\0x13:'\0xe0;\0xcc;!G\0xfa\0x11\0xa9R\0xc6\0x83\0x01\0xd9\0x81
[Vendor:www.ai-thinker.com Version:0.9.2.4]

ready

Back to Index

AT+GMR - View version info

Variant Command Response Function
Execute AT+GMR version, OK Print firmware version
Parameters:
ESP-01 output:
00160901
ESP-12 output:
0018000902-AI03

Back to Index

AT+GSLP - Enter deep-sleep mode

Variant Command Response Function
set AT+GSLP=time time OK Enter deep sleep mode for time milliseconds
parameters:
Example:

AT+GSLP=1500

Note:

Hardware has to support deep-sleep wake up (Reset pin has to be High).

Back to Index

ATE - Enable / Disable echo

Variant Command Response Function
Execute ATE0 OK Disable echo (Doesn’t send back received command)
Execute ATE1 OK Enable echo (Sends back received command before response)
Note:

I haven’t had any luck with this command yet. Both ATE0 and ATE1 return no this fun.
ATE returns OK
This changed with ESP-12 where the command functions exactly as expected!

Back to Index

AT+CWMODE - WIFI mode(station, AP, station + AP)

Variant Command Response Function
Test AT+CWMODE=? +CWMODE:(1-3) OK List valid modes
Query AT+CWMODE? +CWMODE:mode OK Query AP’s info which is connect by ESP8266.
Execute AT+CWMODE=mode OK Set AP’s info which will be connect by ESP8266.
Parameters:
Notes:

ESP-12 came configured as host with ssid set to ESP_A0A3F2, no password, channel 1 You can use AT+CWSAP? to find the current settings.

Back to Index

AT+CWJAP - Connect to AP

Variant Command Response Function
Query AT+CWJAP? + CWJAP:ssid OK Prints the SSID of Access Point ESP8266 is connected to.
Execute AT+CWJAP=ssid,pwd OK Commands ESP8266 to connect a SSID with supplied password.
Parameters:
Example:
AT+CWJAP="my-test-wifi","1234test"  
Example AT+CWJAP?
+CWJAP:"my-test-wifi"  

Back to Index

AT+CWLAP - Lists available APs

Variant Command Response Function
Set AT+CWLAP=ssid,mac,ch +CWLAP:ecn,ssid,rssi,mac OK Search available APs with specific conditions.
Execute AT+CWLAP AT+CWLAP:ecn,ssid,rssi,mac OK Lists available Access Points.
Parameters:
Note:

On ESP-01 I have had no luck with the set version of this command (AT+CWLAP=...). If you know what it does please let me know.
On ESP-12, the Set version of the command allows to see if a certain SSID, with certain MAC on certain channel exists. If it doesit is returned as one line of the Execute version of this command.

Example AT+CWLAP:
+CWLAP:(3,"CVBJB",-71,"f8:e4:fb:5b:a9:5a",1)
+CWLAP:(3,"HT_00d02d638ac3",-90,"04:f0:21:0f:1f:61",1)
+CWLAP:(3,"CLDRM",-69,"22:c9:d0:1a:f6:54",1)
+CWLAP:(2,"AllSaints",-88,"c4:01:7c:3b:08:48",1)
+CWLAP:(0,"AllSaints-Guest",-83,"c4:01:7c:7b:08:48",1)
+CWLAP:(0,"AllSaints-Guest",-83,"c4:01:7c:7b:05:08",6)
+CWLAP:(4,"C7FU24",-27,"e8:94:f6:90:f9:d7",6)
+CWLAP:(2,"AllSaints",-82,"c4:01:7c:3b:05:08",6)
+CWLAP:(3,"QGJTL",-87,"f8:e4:fb:b5:6b:b4",6)
+CWLAP:(4,"50EFA8",-78,"74:44:01:50:ef:a7",6)
+CWLAP:(0,"optimumwifi",-78,"76:44:01:50:ef:a8",6)
+CWLAP:(3,"BHQH4",-95,"18:1b:eb:1a:af:5b",6)
+CWLAP:(3,"NETGEAR49",-86,"84:1b:5e:e0:28:03",7)
+CWLAP:(3,"ngHub_319332NW00047",-56,"20:e5:2a:79:b1:2f",11)
+CWLAP:(3,"BFZR4",-73,"18:1b:eb:1d:c3:91",11)
+CWLAP:(1,"5FFVL",-82,"00:26:b8:b5:c0:f2",11)
+CWLAP:(3,"59G6D",-77,"00:7f:28:6d:91:7b",11)
+CWLAP:(3,"N16FU",-53,"20:cf:30:ce:60:fe",11)
+CWLAP:(3,"ITS",-82,"90:72:40:21:5f:76",11)
+CWLAP:(3,"ITS",-79,"24:a2:e1:f0:04:e4",11)
Example AT+CWLAP="N16FU","20:cf:30:ce:60:fe",11:
+CWLAP:(3,"N16FU",-53,"20:cf:30:ce:60:fe",11)

Back to Index

AT+CWQAP - Disconnect from AP

Variant Command Response Function
Execute AT+CWQAP OK Disconnect ESP8266 from the AP is currently connected to.
Note:

After running this command, if you run AT+CWJAP? it still shows the AP you were connected to before. Back to Index

AT+CWSAP - Configuration of softAP mode

Variant Command Response Function
Query AT+CWSAP? +CWSAP:ssid,pwd,ch,ecn OK Query configuration of ESP8266 softAP mode.
Set AT+CWSAP=ssid,pwd,ch,ecn OK Set configuration of softAP mode.
Parameters:

Example
AT+CWSAP="esp_123","1234test",5,3
AT+CWSAP? => +CWSAP:"esp_123","1234test",5,3

Back to Index

AT+CWLIF - List clients connected to ESP8266 softAP

Variant Command Response Function
Execute AT+CWLIF [ip,other] OK List information on of connected clients.
Parameters:

ip: IP address of a client connected to the ESP8266 softAP other: Other info, look at example. I don’t know what it means yet.

Example (ESP-01):
AT+CWLIF

192.168.4.100,3fff50b4:3fff50ba:3fff50c0:3fff50c6:3fff50cc:3fff50d2

OK
Example (ESP-12):
AT+CWLIF

192.168.4.100,c0:ee:fb:25:33:ec

OK

I ran the command after connecting to the ESP8266 with my cellphone.

Back to Index

AT+CWDHCP - Enable/Disable DHCP

Variant Command Response Function
Set AT+CWDHCP=mode,en OK Enable or disable DHCP for selected mode
Parameters:
Note:

This command doesn’t seem to work on firmware 00160901 (ESP-01) nor 0018000902-AI03 (ESP-12).

Back to Index

AT+CIPSTAMAC - Set MAC address of ESP8266 station

Variant Command Response Function
Query AT+CIPSTAMAC? +CIPSTAMAC:mac OK Print current MAC ESP8266’s address.
Execute AT+CIPSTAMAC=mac OK Set ESP8266’s MAC address.
Parameters:
Example:

AT+CIPSTAMAC="18:aa:35:97:d4:7b"

Note:

This command doesn’t seem to work on firmware 00160901

Back to Index

AT+CIPAPMAC - Set MAC address of ESP8266 softAP

Variant Command Response Function
Query AT+CIPAPMAC? +CIPAPMAC:mac OK Get MAC address of ESP8266 softAP.
Execute AT+CIPAPMAC=mac OK Set mac of ESP8266 softAP.
Parameters:
Example:

AT+CIPAPMAC=”2c:aa:35:97:d4:7b”

Note:

This command doesn’t seem to work on firmware 00160901

Back to Index

AT+CIPSTA - Set IP address of ESP8266 station

Variant Command Response Function
Query AT+CIPSTA? +CIPSTA:ip OK Get IP address of ESP8266 station.
Execute AT+CIPSTA=ip OK Set ip addr of ESP8266 station.
Parameters:
Example:

AT+CIPSTA=”192.168.101.108”

Note:

This command doesn’t seem to work on firmware 00160901

Back to Index

AT+CIPAP - Set ip address of ESP8266 softAP

Variant Command Response Function
Query AT+CIPAP? +CIPAP:ip OK Get ip address of ESP8266 softAP.
Execute AT+CIPAP=ip OK Set ip addr of ESP8266 softAP.
Parameters:
Example:
AT+CIPAP="192.168.5.1"
Note:

This command doesn’t seem to work on firmware 00160901

Back to Index

AT+CIPSTATUS - Information about connection

Variant Command Response Function
Test AT+CIPSTATUS=? OK  
Execute AT+CIPSTATUS STATUS:status +CIPSTATUS:id,type,addr,port,tetype OK Get information about connection.
Parameters:
Note:

On ESP-01 this command returns STATUS:1 instead (no extra info, but status changes) On 0018000902-AI03 this command returns STATUS:2 instead (no extra info, but status changes)

Back to Index

AT+CIPSTART - Establish TCP connection or register UDP port and start a connection

Variant Command Response Function
Set AT+CIPSTART=type,addr,port OK Start a connection as client. (Single connection mode)
Set AT+CIPSTART=id,type,addr,port OK Start a connection as client. (Multiple connection mode)
Test AT+CIPSTART=? [+CIPSTART:(id)(“type”),(“ip address”),(port)] OK List possible command variations)
Parameters:

Back to Index

AT+CIPSEND - Send data

Variant Command Response Function
Test AT+CIPSEND=? OK  
Set AT+CIPSEND=length SEND OK Set length of the data that will be sent. For normal send (single connection).
Set AT+CIPSEND=id,length SEND OK Set length of the data that will be sent. For normal send (multiple connection).
Execute AT+CIPSEND   Send data. For unvarnished transmission mode.

Normal Mode

Parameters:

Unvarnished Transmission Mode

Wrap return “>” after execute command. Enters unvarnished transmission, 20ms interval between each packet, maximum 2048 bytes per packet. When single packet containing “+++” is received, it returns to command mode.

Back to Index

AT+CIPCLOSE - Close TCP or UDP connection

Variant Command Response Function
Test AT+CIPCLOSE=? OK  
Set AT+CIPCLOSE=id OK Close TCP or UDP connection.For multiply connection mode
Execute AT+CIPCLOSE OK Close TCP or UDP connection.For single connection mode
Parameters:
Note:

In server mode, id = 5 has no effect!

Back to Index

AT+CIFSR - Get local IP address

Variant Command Response Function
Test AT+CIFSR=? OK  
Execute AT+CIFSR +CIFSR:ip OK Get local IP address.
Parameters:
Example AT+CIFSR:
10.101.10.134

Back to Index

AT+CIPMUX - Enable multiple connections or not

Variant Command Response Function
Set AT+CIPMUX=mode OK Enable / disable multiplex mode (up to 4 conenctions)
Query AT+CIPMUX? +CIPMUX:mode OK Print current multiplex mode.
Parameters:
NOTE:

This mode can only be changed after all connections are disconnected. If server is started, reboot is required.

Back to Index

AT+CIPSERVER - Configure as server

Variant Command Response Function
Set AT+CIPSERVER=mode[,port] OK Configure ESP8266 as server
Parameters:
NOTE:
  1. Server can only be created when AT+CIPMUX=1
  2. Server monitor will automatically be created when Server is created.
  3. When a client is connected to the server, it will take up one connection,be gave an id.

Back to Index

AT+CIPMODE - Set transfer mode

Variant Command Response Function
Query AT+CIPMODE? +CIPMODE:mode OK Set transfer mode,normal or transparent transmission.
Set AT+CIPMODE=mode OK Set transfer mode,normal or transparent transmission.
Parameters:

Back to Index

AT+CIPSTO - Set server timeout

Variant Command Response Function
Query AT+CIPSTO? +CIPSTO:time Query server timeout.
Set AT+CIPSTO=time OK Set server timeout.
Parameters:

Back to Index

AT+CIUPDATE - update through network

!!! Don’t run this unless you know what you’re doing !!!

### !!! It will likely brick your device !!! Attempts to self-update from the internet.

Variant Command Response Function
Execute AT+CIUPDATE +CIPUPDATE:n OK Start update through network
Parameters:

-n:
- 1: found server
- 2: connect server
- 3: got edition
- 4: start update

Example:
AT+CIUPDATE

+CIUPDATE: 1
+CIUPDATE: 2
+CIUPDATE: 3
+CIUPDATE: 4

\0x02\0x8cl\0x8el\0x8e\0x1cp\0x0c\0x8c\0xf2nn\0xee\0x00l\0x8c\0x8el`
\0x02\0x90\0x12\0x12nnl\0x8cl`\0x02\0x0e\0x02nr\0x8e\0x92\0x92n\0x0c\0x0c
\0x02\0x8c\0x92`\0x02`
\0xf2n\0x0c\0x0c\0x0c\0x9e\0xe0b\0x82nl\0x8c\0x0c\0x8c
\0xf2nn\0xee\0x00\0x0c\0x8e\0x0elp\0xf2n\0xe0\0x10\0x02\0x0c
\0x0cr\0x8c\0x9c\0x9c\0xe2\0xe0\0x0c\0x0c\0x0c
\0x0cb\0x0cn\0xe2|\0x02\0xec\0xecl\0x8c\0x0cb\0x8c\0xf2nn
...forever

Back to Index

+IPD - Receive network data

Variant Command Response Function
Execute   +IPD,len:data Receive network data from single connection.
Execute   +IPD,id,len:data Receive network data from multiple connection.
Parameters:
Note:

I have had no luck with this command so far.

Back to Index

Sources

esp8266 GitHub Wiki