ESP8266 AT Command Reference

ESP8266 AT Command Reference

Communication with the ESP is via serial connection. The designers of the ESP adopted a scheme known as "AT commands" that stems from the age when computers connected to a network via modem (I am even older than that).

The commands that the ESP understands depend on the firmware version. There are a number of those; here are the ones I found a manual for:

• 0.20
• 0.22
• 0.23
• 0.24
• 0.25
• 0.30
• 1.3 At the beginning of 2017 this was the newest version when ordering from Banggood
• 1.4
• 1.5
• 1.5.4
• 2.0.0
• 2.1.0

REM: A change in FW version does not imply a change in supported AT commands.

Communication with the ESP comes in four flavors:

• test command: To query values parameters can assume, use AT+<cmd>=?
• query command: To query the current value of parameters, use AT+<cmd&gt?
• setup command: To set parameters, use AT+<cmd>=<x>
• execute command: To execute a function, use AT+<cmd>

This scheme does not always apply but gives you an idea.

Generally:

• Strings need to be quoted
• Parameter are separated with a comma
• Each command must be followed with CRLF
• 115200Baud is the default speed

I wrote a Java program that communicates with an ESP8266 to try out things before I put them into my AC_ESP8266 library. Testing out of Eclipse is just way faster and more convenient then uploading a new version to the Arduino each time. And, logging on the desktop offers way more possibilities.

Basic

Group	AT Command	Description	Parameters	Response	MQTT-Relevant?
Basic	AT	Test AT startup	-	OK
Basic	AT+RST	Restart module	-	OK	x, for error handling
Basic	AT+GMR	View version info	-	<AT version info> <SDK version info> <compile time> OK	x, for issuing the correct commands
Basic	AT+GSLP	Enter deep-sleep mode	<time in millis>	<time> OK	-
Basic	ATE	AT	commands echo or not	ATE0, ATE1 OK	-
Basic	AT+RESTORE	Factory reset	-	OK	-
Basic	AT+UART	UART configuration, [@deprecated]			-
Basic	AT+UART_CUR	UART current configuration	<baudrate 110-115200>, <databits 5-8>, <stopbits 1: 1, 2: 1.5, 3: 2>, <parity 0: none, 1: odd, 2: even>, <flow control 0: disable, 1: RTS, 2: CTS, 3: RTS + CTS>	OK	-
Basic	AT+UART_DEF	UART default configuration, save to flash			once
Basic	AT+SLEEP	Sleep mode (station mode only)	<sleep mode 0: disable, 1: light, 2: modem>	Query: +SLEEP:<sleep mode> Set: OK	-
Basic	AT+WAKEUPGPIO	Set a GPIO to wake ESP8266 up from light-sleep mode			-
Basic	AT+RFPOWER	Set maximum value of RF TX Power	<power 0-82> in 0.25dBm	OK	-
Basic	AT+RFVDD	Set RF TX Power according to VDD33			-

WLAN

Group	AT Command	Description	Parameters	Response	MQTT-Relevant?
WLAN	AT+CWMODE	Wi-Fi mode(sta/AP/sta+AP), [@deprecated]			-
WLAN	AT+CWMODE_CUR	Wi-Fi mode (station/ AP/ station+AP). Settings not updated in flash.	<mode 1: station, 2: softAP, 3: softAP + station>		-
WLAN	AT+CWMODE_DEF	Wi-Fi default mode(station/ AP/ station+AP). Save to flash.			x - what does saving to flash provide?
WLAN	AT+CWJAP	Connect to AP, [@deprecated]			-
WLAN	AT+CWJAP_CUR	Connect to AP, won’t save to flash (station mode only)	<ssid>,<pwd>[, <bssid>]	Query: +CWJAP_CUR:<ssid>, <bssid>, <channel>, <rssi> OK Set: OK or +CWJAP:<error code 1: connection timeout, 2: wrong password, 3: cannot find target AP, 4: connection failed>	-
WLAN	AT+CWJAP_DEF	Connect to AP, save to flash (station mode only)			x - what does saving to flash provide?
WLAN	AT+CWLAPOPT	Set the configuration of command AT+CWLAP	<sort enable 0: no sort, 1: sort by rssi>,<mask b0: ECN, b1: SSID, b2: RSSI, b3: MAC, b4: chn, b5: freq offset, b6: freq calibration>
WLAN	AT+CWLAP	Lists available APs	<ssid>[, <mac>, <ch>]	+CWLAP:<ecn 0: open, 1: WEP, 2: WPA_PSK, 3: WPA2_PSK, 4: WPA_WPA2_PSK, 5: WPA2_Enterprise>, <ssid>, <rssi>, <mac>, <ch>, <freq offset>, <freq calibration> OK depending on options set with CWLAPOPT	maybe, for selecting a WLAN
WLAN	AT+CWQAP	Disconnect from AP	-	OK	maybe, for error handling
WLAN	AT+CWSAP	Set configuration of ESP8266 soft-AP, [@deprecated]			-
WLAN	AT+CWSAP_CUR	Set current configuration of ESP8266 soft-AP. Settings not updated in flash.	<ssid>, <pwd>, <chl>, <ecn 0, 2, 3, 4>[, <max conn 1-4>][, <ssid hidden 0: broadcast, 1: don't broadcast>]	Query: +CWSAP_CUR:<ssid>, <pwd>, <chl>, <ecn>, <max conn>, <ssid hidden> Set: OK or ERROR	-
WLAN	AT+CWSAP_DEF	Set configuration of ESP8266 soft-AP. Save changes to flash.			-
WLAN	AT+CWLIF	Get station IP which is connected to ESP8266 soft-AP	-	<IP addr>, <mac> OK	-
WLAN	AT+CWDHCP	Enable/Disable DHCP, [@deprecated]			-
WLAN	AT+CWDHCP_CUR	Enable/Disable DHCP, changes not save to flash			-
WLAN	AT+CWDHCP_DEF	Enable/Disable DHCP, save changes to flash			-
WLAN	AT+CWDHCPS_CUR	Set IP range of DHCP server, changes not save to flash			-
WLAN	AT+CWDHCPS_DEF	Set IP range of DHCP server, save changes to flash			-
WLAN	AT+CWAUTOCONN	Connect to AP automatically on power-up	<enable 0: disable, 1: enable auto-connect on startup>		x - quite possibly!
WLAN	AT+CIPSTAMAC	Set MAC address of ESP8266 station [@deprecated]			-
WLAN	AT+CIPSTAMAC_CUR	Set MAC address of ESP8266 station. Changes not save to flash.			-
WLAN	AT+CIPSTAMAC_DEF	Set MAC address of ESP8266 station. Save changes to flash.			-
WLAN	AT+CIPAPMAC	Set MAC address of ESP8266 soft-AP [@deprecated]			-
WLAN	AT+CIPAPMAC_CUR	Set MAC address of ESP8266 soft-AP. Changes not save to flash.			-
WLAN	AT+CIPAPMAC_DEF	Set MAC address of ESP8266 soft-AP. Save changes to flash.			-
WLAN	AT+CIPSTA	Set IP address of ESP8266 station, [@deprecated]			-
WLAN	AT+CIPSTA_CUR	Set IP address of ESP8266 station. Changes not save to flash.			x - to query
WLAN	AT+CIPSTA_DEF	Set IP address of ESP8266 station. Save changes to flash.			-
WLAN	AT+CIPAP	Set IP address of ESP8266 soft-AP, [@deprecated]			-
WLAN	AT+CIPAP_CUR	Set IP address of ESP8266 soft-AP. Changes not save to flash.			-
WLAN	AT+CIPAP_DEF	Set IP address of ESP8266 soft-AP. Save changes to flash.			-
WLAN	AT+CWSTARTSMART	Start SmartConfig (for AirKiss or ESP-TOUCH)			-
WLAN	AT+CWSTOPSMART	Stop SmartConfig			-
WLAN	AT+CWSTARTDISCOVER	Start the mode that ESP8266 can be found by WeChat			-
WLAN	AT+CWSTOPDISCOVER	Stop the mode that ESP8266 can be found by WeChat			-
WLAN	AT+WPS	Set WPS function			-
WLAN	AT+MDNS	Set MDNS function			-

TCP

Group	AT Command	Description	Parameters	Response	MQTT-Relevant?
TCP	AT+CIPSTATUS	Get connection status		STATUS:<stat: 2: connected to AP, obtained IP, 3: TCP or UDP connection created, 4: TCP or UDP disconnected, 5: not connected to AP> +CIPSTATUS:<link ID 0-4>, <type TCP or UDP>, <remote_IP>, <remote_port>, <local_port>, <tetype 0: client, 1: server>	x
TCP	AT+CIPDOMAIN	DNS function			-
TCP	AT+CIPSTART	Establish TCP connection, UDP transmission or SSL connection (only one at the same time, high memory consumption)	<link ID 0-4>,<type TCP, UDP, SSL>, <remote IP>, <remote port>[, <TCP keep alive>]		x
TCP	AT+CIPSSLSIZE	Set the size of SSL buffer			maybe, SSL would be great
TCP	AT+CIPSEND	Send data	AT+CIPSEND=<link ID>, <length> then receives serial data until length is reached, then ERROR or SEND OK	x
TCP	AT+CIPSENDEX	Send data, if <length> or "\0" is met, data will be sent
TCP	AT+CIPSENDBUF	Write data into TCP-send-buffer
TCP	AT+CIPBUFRESET	Reset segment ID count
TCP	AT+CIPBUFSTATUS	Check status of TCP-send-buffer (not for SSL connections)
TCP	AT+CIPCHECKSEQ	Check if a specific segment is sent or not
TCP	AT+CIPCLOSE	Close TCP/UDP/SSL connection			x
TCP	AT+CIFSR	Get local IP address		+ CIFSR:<IP address> OK	x
TCP	AT+CIPMUX	Set multiple connections mode			x - to select single mode, but do we need single mode?
TCP	AT+CIPSERVER	Configure as server			-
TCP	AT+CIPMODE	Set transmission mode			- not used so far
TCP	AT+SAVETRANSLINK	Save transparent transmission link to flash			- I get the impression this creates a TCP connection and after that, serial talks transparently to that connection
TCP	AT+CIPSTO	Set timeout when ESP8266 runs as TCP server			-
TCP	AT+CIUPDATE	Upgrade firmware through network			-
TCP	AT+PING	Function PING	<IP>	+<time> OK Or ERROR	maybe, for error handling
TCP	AT+CIPDINFO	Show remote IP and remote port with "+IPD"			-