Here's A Compilation Of All HC-05 Bluetooth AT Commands. For Beginners, See Arduino Bluetooth. ... Set/Check Connect Mode:

Updated: October 18, 2022

The HC-05 is a common Bluetooth module used in many microcontroller projects. Here's a compilation of all HC-05 Bluetooth AT Commands. For beginners, see Arduino Bluetooth.

Contents

Toggle

• Setting HC-05 to AT Command Mode
• Test command
• Reset
• Get firmware version
• Restore default
• Get module address
• Set/Check module name:
• Get the Bluetooth device name:
• Set/Check module mode:
• Set/Check device class
• Set/Check GIAC (General Inquire Access Code)
• Set/Check — Query access patterns
• Set/Check PIN code:
• Set/Check serial parameter:
• Set/Check connect mode:
• Set/Check fixed address:
• Set/Check LED I/O
• Set PIO output
• Set/Check – scan parameter
• Set/Check – SNIFF parameter
• Set/Check security mode
• Delete Authenticated Device
• Delete All Authenticated Device
• Search Authenticated Device
• Get Authenticated Device Count
• Most Recently Used Authenticated Device
• Get the module working state
• Initialize the SPP profile lib
• Inquiry Bluetooth Device
• Cancel Inquiring Bluetooth Device
• Equipment Matching
• Connect Device
• Disconnect
• Energy-saving mode
• Exerts Energy-saving mode
• Pairing Two HC-05 Modules

Setting HC-05 to AT Command Mode

By default, the HC-05 is configured in data mode. In this mode, the module acts like a serial bridge. To put into AT command mode the KEY pin must be set (high).

However, there are modules where the KEY pin is missing or is not wired to the actual KEY pin of the IC. To solve this, wire pin 34 of the IC to 3.3 V:

The HC-05 is now in command mode if the red LED flashes once every two seconds.

The following commands require that the HC-05 is connected to the Arduino as a serial device. Below is an example wiring diagram and sketch/code:

#include <SoftwareSerial.h> SoftwareSerial Bluetooth(7,8); void setup() { Serial.begin(9600); Bluetooth.begin(9600); } void loop() { while (Serial.available()) { delay(1); Bluetooth.write(Serial.read()); } while (Bluetooth.available()) { Serial.write(Bluetooth.read()); } }

Test command

Command	Response	Parameter
AT	OK	-

Reset

Command	Response	Parameter
AT+RESET	OK	-

Get firmware version

Command	Response	Parameter
AT+VERSION?	+VERSION:<Param> OK	Param : firmware version

Example:

AT+VERSION? +VERSION:2.0-20100601 OK

Restore default

Command	Response	Parameter
AT+ORGL	OK	-

Default state:

Slave mode, pin code :1234, device name: H-C-2010-06-01 ,Baud 38400bits/s.

Get module address

Command	Response	Parameter
AT+ADDR?	+ADDR:<Param> OK	Param: address of Bluetooth module

Bluetooth address: NAP: UAP : LAP

Example:

AT+ADDR? +ADDR:1234:56:abcdef OK

Set/Check module name:

Command	Response	Parameter
AT+NAME=<Param>	OK	Param: Bluetooth module name (Default :HC-05)
AT+NAME?	+NAME:<Param> OK or FAIL

Example:

AT+NAME=HC-05 ;set the module name to “HC-05” OK AT+NAME? +NAME: HC-05 OK

Get the Bluetooth device name:

Command	Response	Parameter
AT+RNAME?<Param1>	+NAME:<Param2> OK or FAIL	Param1,Param 2 : the address of Bluetooth device

Example: (Device address 00:02:72:od:22:24，name：HC-05)

AT+RNAME? 0002，72，od2224 +RNAME:HC-05 OK

Set/Check module mode:

Command	Response	Parameter
AT+ROLE=<Param>	OK	0 - Slave 1 - Master 2 - Slave-Loop
AT+ ROLE?	+ROLE:<Param> OK

Set/Check device class

Command	Response	Parameter
AT+CLASS=<Param>	OK	Param: Device Class
AT+CLASS?	+CLASS:<Param> OK or FAIL

Set/Check GIAC (General Inquire Access Code)

Command	Response	Parameter
AT+IAC=<Param>	OK or FAIL	Param: GIAC (Default : 9e8b33)
AT+IAC	+IAC:<Param> OK

Example:

AT+IAC=9e8b3f OK AT+IAC? +IAC: 9e8b3f OK

Set/Check -- Query access patterns

Command	Response	Parameter
AT+INQM=<Param>,<Param2>, <Param3>	OK or FAIL	Param: 0 -- inquiry_mode_standard 1 -- inquiry_mode_rssi Param2: Maximum number of Bluetooth devices to respond to Param3: Timeout (1-48 : 1.28s to 61.44s)
AT+ INQM?	+INQM ：<Param>,<Param2>, <Param3> OK

Example:

AT+INQM=1,9,48 OK AT+INQM +INQM:1, 9, 48 OK

Set/Check PIN code:

Command	Response	Parameter
AT+PSWD=<Param>	OK	Param: PIN code (Default 1234)
AT+PSWD?	+ PSWD : <Param> OK

Set/Check serial parameter:

Command	Response	Parameter
AT+UART=<Param>,<Param2>,< Param3>	OK	Param1: Baud Param2: Stop bit Param3: Parity
+UART=<Param>,<Param2>, <Param3> OK

Example:

AT+UART=115200,1,2, OK AT+UART? +UART:115200,1,2 OK

Set/Check connect mode:

Command	Response	Parameter
AT+CMODE=<Param>	OK	Param: 0 - connect fixed address 1 - connect any address 2 - slave-Loop
+ CMODE:<Param> OK

Set/Check fixed address:

Command	Response	Parameter
AT+BIND=<Param>	OK	Param: Fixed address (Default 00:00:00:00:00:00)
AT+BIND?	+ BIND:<Param> OK

Example:

AT+BIND=1234,56,abcdef OK AT+BIND? +BIND:1234:56:abcdef OK

Set/Check LED I/O

Command	Response	Parameter
AT+POLAR=<Param1,<Param2>	OK	Param1: 0- PIO8 low drive LED 1- PIO8 high drive LED Param2: 0- PIO9 low drive LED 1- PIO9 high drive LED
+ POLAR=<Param1>,<Param2> OK

Set PIO output

Command	Response	Parameter
AT+PIO=<Param1>,<Param2>	OK	Param1: PIO number Param2: PIO level 0- low 1- high

Example:

;PIO10 output high level AT+PI0=10,1 OK

Set/Check – scan parameter

Command	Response	Parameter
AT+IPSCAN=<Param1>,<Param2 >,<Param3>,<Param4>	OK	Param1: Query time interval Param2: Query duration Param3: Paging interval Param4: Call duration
AT+IPSCAN?	+IPSCAN:<Param1>,<Param2>,<Param3>,<Param4> OK

Example:

AT+IPSCAN =1234,500,1200,250 OK AT+IPSCAN? +IPSCAN:1234,500,1200,250

Set/Check – SNIFF parameter

Command	Response	Parameter
AT+SNIFF=<Param1>,<Param2>, <Param3>,<Param4>	OK	Param1: Max time Param2: Min time Param3: Retry time Param4: Time out
AT+SNIFF?	+SNIFF:<Param1>,<Param2>,<Param3>,<Param4> OK

Set/Check security mode

Command	Response	Parameter
AT+SENM=<Param1>,<Param2>	OK or FAIL	Param1: 0 --sec_mode0+off AT+ SENM? + SENM:<Param1>,<Param2> 1——sec_mode1+non_secure 2 -- sec_mode2_service 3 -- sec_mode3_link 4 -- sec_mode_unknown Param2: 0 -- hci_enc_mode_off 1 -- hci_enc_mode_pt_to_pt 2 -- hci_enc_mode_pt_to_pt_and_bcast

Delete Authenticated Device

Command	Response	Parameter
AT+PMSAD=<Param>	OK	Param: Authenticated Device Address

Example:

AT+PMSAD =1234,56,abcdef OK

Delete All Authenticated Device

Command	Response	Parameter
AT+ RMAAD	OK

Search Authenticated Device

Command	Response	Parameter
AT+FSAD=<Param>	OK or FAIL	Param: Device address

Get Authenticated Device Count

Command	Response	Parameter
AT+ADCN?	+ADCN：<Param> OK	Param: Device Count

Most Recently Used Authenticated Device

Command	Respond	Parameter
AT+MRAD?	+ MRAD：<Param> OK	Param: Recently Authenticated Device Address

Get the module working state

Command	Response	Parameter
AT+ STATE?	+ STATE：<Param> OK	Param: “INITIALIZED” “READY” “PAIRABLE” “PAIRED” “INQUIRING” “CONNECTING” “CONNECTED” “DISCONNECTED” “NUKNOW”

Initialize the SPP profile lib

Command	Response	Parameter
AT+INIT	OK or FAIL	-

Inquiry Bluetooth Device

Command	Response	Parameter
AT+INQ	+INQ: <Param1>， <Param2>， <Param3> …. OK	Param1：Address Param2：Device Class Param3：RSSI Signal strength

Example:

AT+INIT OK AT+IAC=9e8b33 OK AT+CLASS=0 AT+INQM=1,9,48 AT+INQ +INQ:2:72:D2224,3E0104,FFBC +INQ:1234:56:0,1F1F,FFC1 +INQ:1234:56:0,1F1F,FFC0 +INQ:1234:56:0,1F1F,FFC1 +INQ:2:72:D2224,3F0104,FFAD +INQ:1234:56:0,1F1F,FFBE +INQ:1234:56:0,1F1F,FFC2 +INQ:1234:56:0,1F1F,FFBE +INQ:2:72:D2224,3F0104,FFBC OK

Cancel Inquiring Bluetooth Device

Command	Response	Parameter
AT+ INQC	OK	-

Equipment Matching

Command	Response	Parameter
AT+PAIR=<Param1>,<Param2>	OK or FAIL	Param1：Device Address Param2：Time out

Connect Device

Command	Response	Parameter
AT+LINK=<Param>	OK or FAIL	Param：Device Address

Example:

AT+FSAD=1234,56,abcdef OK AT+LINK=1234,56,abcdef OK

Disconnect

Command	Response	Parameter
AT+DISC	+DISC:SUCCESS OK or +DISC:LINK_LOSS OK or +DISC:NO_SLC OK or +DISC:TIMEOUT OK or +DISC:ERROR OK	Param：Device Address

Energy-saving mode

Command	Response	Parameter
AT+ENSNIFF=<Param>	OK	Param：Device Address

Exerts Energy-saving mode

Command	Response	Parameter
AT+ EXSNIFF =<Param>	OK	Param：Device Address

Pairing Two HC-05 Modules

Use an FTDI USB to Serial converter to configure the bluetooth module once it’s in command mode (how to set in command mode). Then use Arduino’s serial monitor to send out commands. The default baud rate for command mode is 38400. One module is the master device while the other is the slave device. Pairing configuration is done through the master device.

Step 1: Check if the HC-05 master is in command mode:

AT > OK

Step 2: Reset the configurations to their default values:

AT+ORGL > OK

Step 3: Set the module to master:

AT+ROLE=1 > OK

Step 4: Reset the module:

AT+RESET > OK

Step 5: Wait, then initialize:

AT+INIT > OK

Step 6:  Forget all the previous connections:

AT+RMAAD > OK

Step 7: Determine MAC address of slave device. Set slave device to command mode and issue command:

AT+INQ > +INQ:98D3:31:FC20A9,1F00,7FFF

Here, it shows that the slave device has a MAC address of 98D3:31:FC20A9. The 1F00 is the device class while the 7FFF is the received signal strength indicator (RSSI).

Step 8: Back to master module; pair with the slave device:

AT+PAIR=98D3,31,FC20A9,20 > OK

After pairing, the LED on the master module will start flashing with about two seconds of pause.

Step 9: Bind the master and slave devices:

AT+BIND=98D3,31,FC20A9 > OK

Step 10: Link the two devices:

AT+LINK=98D3,31,FC20A9 > OK

If successful, both the master and slave device's LED will now blink twice followed by about two seconds of pause.

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