AT Command Reference

Each BlueSMiRF v2 firmware comes with a set of AT commands to read or change the configuration. The following set of AT commands are similar to previous BlueSMiRF AT commands. Let's go over some of these commands!

AT Commands

Note

Command mode cannot be entered 60 seconds after power-on or resetting. This setting can be configured with the command AT-MaxCommandTimeMs.

BlueSMiRF radios are very flexible. By default, the radio is looking for serial communication at 115200 bps. Open the terminal of your choice. Then enter $$$ and wait for an OK. Both the CONNECT and STATUS LEDs will fade in and fade out whenever the board is in Command Mode. At this point, the radio is now ready for an AT command.

BlueSMiRF v2 Connected to Serial Terminal and in Command Mode

Note

Depending on your serial terminal's settings, you may not see the characters that are being sent. You can try turning on the local echo to view the characters. However, keep in mind that any characters sent when the BlueSMiRF v2 is in command mode will already be echoed back.

Note

The device can also be configured by connecting over Bluetooth and entering $$$.

Below is a brief list of commands. The BlueSMiRF will recognize commands with capital and lower case letters since the commands are not case sensitive.

AT Command	Command Description
$$$	Enter Command Mode
AT	Reports OK
AT?	Display this help text
ATA	Display all settings
ATB	Display Bluetooth settings
ATC	Check for new firmware
ATD	Display the debug settings
ATF	Restore factory settings
ATM	Display MAC address
ATP	Start pairing process
ATS	Display serial settings
ATU	Update Firmware
ATV	Display firmware version
ATW	Save current settings to NVM
ATX	Exit command mode
ATY	Display system settings
ATZ	Reboot the system
AT-Param=xxx	Set parameter's value to xxx by name (Param)
AT-Param?	Print parameter's current value by name (Param)
AT-?	Display the setting values
AT Commands

A parameter is set using the AT- prefix, followed by the name of the command with an equals sign and the value to set. For example, sending AT-SerialSpeed=115200 followed by the ENTER key (or a carriage return) will change the serial interface speed to 115200bps. This setting can be stored in NVM (non-volatile memory) by sending the ATW command.

To query a setting, send the AT command without a value and the device will respond with the current value. For example, sending AT-SerialSpeed followed by the ENTER key will generate the response 115200 followed by OK.

The commands are best discussed in groups:

• Bluetooth Commands
• Serial Commands
• System Commands

Bluetooth Commands

Below is a table for Bluetooth commands, a short description of the command, and its factory default value (if applicable). Right after the table, there is also a list which provides a detailed explanation of each parameter as well.

AT Command	Command Description	Factory Default Value
AT-BluetoothConnectRetries	Number of retries of a paired connection	5
AT-BluetoothConnectTimeoutMs	Milliseconds before a paired connection attempt times out	3000
AT-BluetoothEscapeCharacter	The character received from the remote system, sought to enter command mode	+
AT-BluetoothNickname	User configurable name to broadcast over Bluetooth during discovery	"BlueSMiRF-ABCD", where ABCD is the last four hex digits of the Bluetooth MAC
AT-BluetoothPairedMac	MAC address of the unit that the user wants to connect to at startup
AT-BluetoothPairedName	Name of the unit that the user wants to connect to at startup
AT-BluetoothPin	Pin to enter during pairing - only required for older Bluetooth devices	1234
AT-BluetoothRxSize	Bluetooth receive buffer size	2048
AT-BluetoothTxSize	Bluetooth write buffer size	1024
AT-BluetoothType	Bluetooth protocol used for communication	0
Bluetooth Commands

• BluetoothConnectRetries — If this device has a paired MAC or name, at power up it will attempt to connect to this paired device. A connection is not guaranteed, and the connection will be re-tried this number of times before going into passive, discoverable mode.

• BluetoothConnectTimeoutMs — When this device is connecting to a paired device, if this number of milliseconds expires before a connection is made, the device will attempt to reconnect to the paired device.

• BluetoothEscapeCharacter — This is the character that must be transmitted by a remote device to enter command mode remotely over the Bluetooth connection.

  Note

  Escape characters are ignored after MaxCommandTimeMs number of milliseconds and within MinEscapeTimeMs of other incoming characters.

• BluetoothNickname — The name that is broadcast when other devices are scanning for devices to pair to.

• BluetoothPairedMac — The MAC address of the BlueSMiRF that this device should pair to at power-on. Use the ATM command on the remote device to display its MAC address. This command is not normally used; use the button pairing method for an easier way to pair two devices.

• BluetoothPairedName — The name of the BlueSMiRF that this device should pair to at power-on. Use the BluetoothNickname command on the remote device to change its paired name. This command is not normally used; use the button pairing method for an easier way to pair two devices.

• BluetoothPin — The pin that is needed during pairing. Only needed on very old Bluetooth USB dongles.

• BluetoothRxSize — The size of the Bluetooth receive buffer. Increase if a large amount of data is coming into the BlueSMiRF over Bluetooth, before the speed of the serial interface can output it.

• BluetoothTxSize — The size of the Bluetooth transmit buffer. Increase if a large amount of data needs to be transmitted over Bluetooth but the connection between devices is poor and multiple retransmissions occur.

• BluetoothType — Controls the Bluetooth protocol. This parameter accepts a 0, 1, and 2 for the Bluetooth Protocol as listed below. Note that only the SPP protocol supports pairing.

  • Protocol 0 = Serial Port Profile (SPP)
  • Protocol 1 = Bluetooth Low-Energy (BLE)
  • Protocol 2 = Radio off

Serial Commands

Below is a table for serial commands, a short description of the command, and its factory default value (if applicable). Right after the table, there is also a list which provides a detailed explanation of each parameter as well.

AT Command	Command Description	Factory Default Value
AT-FlowControl	Enable the use of CTS/RTS flow control signals	0
AT-InvertCts	Invert the input of CTS	0
AT-InvertRts	Invert the output of RTS	0
AT-PartialFrameTimeoutMs	Send partial buffer if time expires	50
AT-RtsStartSendingPercent	Percent of serialReceiveBuffer that is free when RTS is asserted	25
AT-RtsStopSendingPercent	Percent of serialReceiveBuffer that is free when RTS is deasserted	5
AT-SerialReceiveBufferSize	Serial receive buffer size	51200
AT-SerialSpeed	The baud rate that the BlueSmiRF operates at.	115200
AT-SerialTransmitBufferSize	Buffer size to receive bytes from Bluetooth	10240
Serial Commands

• FlowControl - If flow control is enabled, the BlueSMiRF v2 will send data when its CTS pin is driven low (the host system is telling the radio to transmit). If flow control is enabled, BlueSMiRF v2 will drive its RTS low if its serial buffer is full (the radio is telling the host system to hold its horses). By default, flow control is turned off.

• InvertCts - By default, InvertCts is false and CTS is high when data is allowed to flow. Enable InvertCts to do the opposite.

• InvertRts - By default, InvertRts is false and RTS is high when data is allowed to flow. Enable InvertRts to do the opposite.

• PartialFrameTimeoutMs - The number of milliseconds of timeout before a partial packet is sent. For example, if a partial frame of 12 bytes is received, the radio will wait this amount for more bytes before initiating a transmission.

• RtsStartSendingPercent - Percent of serialReceiveBuffer that is free when RTS is asserted. Default of 25% of serialReceiveBuffer.

• RtsStopSendingPercent - Percent of serialReceiveBuffer that is free when RTS is deasserted. Default of 5% of serialReceiveBuffer.

• SerialReceiveBufferSize - Buffer size to receive serial data from the serial port, to be sent over Bluetooth. The default is 51200.

• SerialSpeed - The baud rate that the BlueSMiRF operates at. Discrete values 2400, 4800, 9600, 14400, 19200, 38400, 57600, 115200 (default), 230400, 460800, and 921600bps are allowed.

• SerialTransmitBufferSize - Buffer size to receive bytes from Bluetooth, waiting to be printed out the UART. The default is 10240.

System Commands

Below is a table for system commands, a short description of the command, and its factory default value (if applicable). Right after the table, there is also a list which provides a detailed explanation of each parameter as well.

AT Command	Command Description	Factory Default Value
AT-EscapeCharacter	The character sought to enter command mode	$
AT-EscapeCharacterCount	The number of escape characters required to enter command mode	3
AT-LedStyle	Controls the behavior of the Status and Connect LEDs	0
AT-MaxCommandTimeMs	After this time in milliseconds, command mode cannot be entered	60000
AT-MinEscapeTimeMs	Serial traffic must stop this amount of milliseconds before an escape character is recognized	2000
AT-WiFiPassword	Password for the SSID, used for over-the-air-updates
AT-WiFiSSID	SSID used for over-the-air-updates
System Commands

• EscapeCharacter — The character that must be entered a number of times (EscapeCharacterCount) to enter configuration mode. An escape character must be entered before the max time of MaxCommandTimeMs and after MinEscapeTimeMs.

• EscapeCharacterCount — The number of escape characters needed before command mode is entered. Set to 0 to disable.

• LedStyle - Controls how the LEDs behave: CLASSIC = 0, SERIAL_TRAFFIC = 1, OFF = 2.

  • CLASSIC mode (default) = 0 — The STATUS LED blinks with TX/RX traffic.

  • SERIAL_TRAFFIC mode = 1 — The CONNECT LED blinks with TX traffic and the STATUS LED blinks with RX traffic.

  • OFF mode = 2 — The CONNECT and STATUS LEDs are turned off.

• MaxCommandTimeMs — Once this number of milliseconds has passed, command mode cannot be entered. This is used as a method to prevent a remote system from accidentally entering command mode.

• MinEscapeTimeMs — This number of milliseconds must pass between the last serial character received and an escape character. This is used as a method to prevent a remote system from accidentally entering command mode.

• WiFiPassword — The password for the local WiFi used for firmware updates.

• WiFiSSID — The SSID for the local WiFi used for firmware updates.