AT Command Set¶
Here is a list of AT commands. Some of them can only work on the ESP32 series, so they are marked as [ESP32 Only] at the beginning; others without any mark can work on both the ESP8266 and ESP32 series.
- Basic AT Commands
- Wi-Fi AT Commands
- TCP-IP AT Commands
- [ESP32 Only] Bluetooth® Low Energy AT Commands
- [ESP32 Only] Bluetooth® AT Commands
- MQTT AT Commands
- HTTP AT Commands
- [ESP32 Only] Ethernet AT Commands
- [ESP8266 Only] Signaling Test AT Commands
- [ESP32 & ESP32S2 Only] Driver AT Commands
- AT Command Set Comparison
It is strongly recommended to read the following sections for some common information on AT commands before you dive into the details of each command.
AT Command Types¶
Generic AT command has four types:
|Test Command||AT+<CommamdName>=?||Query the Set Commands’ internal parameters and their range of values.|
|Query Command||AT+<CommamdName>?||Return the current value of parameters.|
|Set Command||AT+<CommamdName>=<…>||Set the value of user-defined parameters in commands, and run these commands.|
|Execute Command||AT+<CommamdName>||Run commands with no user-defined parameters.|
Not all AT commands support all of the four types mentioned above.
Square brackets [ ] designate parameters that can be omitted. The default value of the parameter will be used instead when you omit it.
Below are examples of entering the command AT+CWJAP with some parameters omitted:
If the parameter you want to omit is followed by a parameter(s), you must give a
,to indicate it.
String values need to be included in double quotation marks.
Escape character syntax is needed if a string contains special characters, such as
\\: escape the backslash itself
\,: escape comma which is not used to separate each parameter
\": escape double quotation mark which is not used to mark string input
<any>character means that drop backslash symbol and only use
The default baud rate of AT command is 115200.
The length of each AT command should be no more than 256 bytes.
AT commands end with a new-line (CR-LF), so the serial tool should be set to “New Line Mode”.
Definitions of AT command error codes are provided in AT API Reference:
AT Commands with Configuration Saved in the Flash¶
Configuration settings entered by the following AT Commands will always be saved in the flash NVS Area, so they can be automatically restored on reset:
Saving of configuration settings by several other commands can be switched on or off with AT+SYSSTORE command.
There are two types of ESP-AT messages returned from the ESP-AT command port:
ESP-AT Response Messages (passive)
Each ESP-AT command input returns response messages to tell the sender the result of the ESP-AT command.
ESP-AT Message Reports (active)
ESP-AT will report important state changes or messages in the system.
|AT Response Messages||Description|
|OK||AT command process done and return OK|
|ERROR||AT command error or error occurred during the execution|
|SEND OK||Data has been sent to the protocol stack (specific to AT+CIPSEND and AT+CIPSENDEX command)|
|SEND FAIL||Error occurred during sending the data to the protocol stack (specific to AT+CIPSEND and AT+CIPSENDEX command|
||Response to the sender that describes AT command process results in details|
|ESP-AT Message Report||Description|
|ready||The ESP-AT firmware is ready|
|busy p…||Busy processing. The system is in process of handling the previous command, thus CANNOT accept the new input|
||Error code for different command|
|Will force to restart!!!||Module restart right now|
|Smart get wifi info||Smartconfig has got the SSID and PASSWORD information|
|smartconfig connected wifi||Smartconfig done. ESP-AT has connected to the Wi-Fi|
|WIFI CONNECTED||Wi-Fi station interface has connected to an AP|
|WIFI GOT IP||Wi-Fi station interface has got the IPv4 address|
|WIFI DISCONNECT||Wi-Fi station interface has disconnected from an AP|
|+ETH_CONNECTED||Ethernet station interface has connected|
|+ETH_GOT_IP||Ethernet station interface has got the IPv4 address|
|+ETH_DISCONNECTED||Ethernet station interface has disconnected|
|[<conn_id>,]CONNECT||A network connection of which ID is
|[<conn_id>,]CLOSED||A network connection of which ID is
|+LINK_CONN||Detailed connection information of TCP/UDP/SSL|
|+STA_CONNECTED: <sta_mac>||A station has connected to the Wi-Fi softAP interface of ESP-AT|
|+DIST_STA_IP: <sta_mac>,<sta_ip>||The Wi-Fi softAP interface of ESP-AT distributes an IP address to the station|
|+STA_DISCONNECTED: <sta_mac>||A station disconnected from the Wi-Fi softAP interface of ESP-AT|
|>||ESP-AT is waiting for more data to be received|
||ESP-AT has already received
|+IPD||ESP-AT received the data from the network|
|SEND Canceled||Cancel to send in Wi-Fi passthrough mode|
||Has reached the maximum connection counts for server|
|+QUITT||ESP-AT quits from the Wi-Fi passthrough mode|
|NO CERT FOUND||No valid device certificate found in custom partition|
|NO PRVT_KEY FOUND||No valid private key found in custom partition|
|NO CA FOUND||No valid CA certificate found in custom partition|
|+MQTTCONNECTED||MQTT connected to the broker|
|+MQTTDISCONNECTED||MQTTT disconnected from the broker|
|+MQTTSUBRECV||MQTT received the data from the broker|
|+MQTTPUB:FAIL||MQTT failed to publish data|
|+MQTTPUB:OK||MQTT publish data done|
|+BLECONN||A Bluetooth LE connection established|
|+BLEDISCONN||A Bluetooth LE connection ends|
|+READ||A read operation from Bluetooth LE connection|
|+WRITE||A write operation from Bluetooth LE connection|
|+NOTIFY||A notification from Bluetooth LE connection|
|+INDICATE||An indication from Bluetooth LE connection|
|+BLESECNTFYKEY||Bluetooth LE SMP key|
|+BLEAUTHCMPL||Bluetooth LE SMP pairing completed|