GS-BT2416C2

GS-BT2416C2.AT1 Bluetooth class 2 module with embedded SPP SW Features ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Bluetooth specification V.1.2 compliant Transmission rate up to 721 Kbps Output power class 2 ( 0 dBm typical) Working distance up to 10 meters ACL & SCO links AFH interferance resistance Supports USB (1.1) /UART/PCM (Pulse Code Modulation)/SPI/ I²C interfaces Optimized link manager and control Support wireless LAN coexistence in collocated scenario Integrated 4Mbit flash, 64Kbytes RAM, 4KBytes ROM 3.3V single supply voltage Hardware based UART flow control Description ST Bluetooth Modules are highly integrated for easy implementation in embedded applications. Class 2 modules enable wireless communication with other Bluetooth enabled devices up to 10 m away. The GS-BT2416C2.AT1 integrates on a unique FR4 PCB support: BT 1.2 radio and baseband, memory, 32 KHz and 13 MHz oscillator as well Vreg. The Module embeds a complete lower and upper Bluetooth stack up to the application support layers including the Generic Port Profile (GAP) and Serial Port Profile (SPP), as well the AT Command Interpreter. The antenna has not been included in order to grant a degree of freedom to the user in selecting the most suitable design and placement between external and integrated antenna that could be SMA aerial or a low cost antenna trace designed on PCB. For more details pleas refer to GS-BT2416C2DBAT1 Application Note. The GS-BT2416C2.AT1 is the SPP with AT command module of the GS-BT2416C2.xx series. GS-BT2416C2.AT1 is BQB qualified. Conformance testing through Bluetooth qualification program enables a fast time to market after system integration by ensuring a high degree of compliance and interoperability. Applications ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Serial cable replacement Industrial control Laptops POS terminals Data acquisition equipment Internet access points Machine Control Sensor monitoring Robotic and bionic control Security control Patient monitoring Audio gateway applications Hands-free sets Wireless printers Cordless terminals Laptops, PCs and accessories Hand held devices and accessories HID devices (keyboard, mouse, joystick, game controller...) Certifications ■ CE Compliant (IMQ Exp.Opinion 0081AREF00017 – Safety EN60950-1 (2001) – EMC EN301 489 17V1.2.1 – Radio ES 300 328 V1.6. FCC certified on GS-BT2416C2DBAT1 (for a more exhaustive explanation, please refer to GS-BT2416C2DB Application Note) FCC ID: S9N16C2 BQB qualified device BQB ID: B012535 1/32 www.st.com 32 ■ Order code ■ GS-BT2416C2.AT1 ■ September 2007 Rev 1 Contents GS-BT2416C2.AT1 Contents 1 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1 1.2 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Operating ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1 DC I/O specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3 Bluetooth section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1 RF performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 Integrate software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.1 4.2 4.3 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Command interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Usage scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.1 Antenna reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6 7 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 7.1 7.2 Pin connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 8 Mechanical dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Appendix A AT command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 A.1 8.1 A.2 A.3 A.4 A.5 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Modes of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Interfaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Bluetooth features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 AT command reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2/32 GS-BT2416C2.AT1 Contents A.6 A.7 A.8 A.9 A.10 A.11 A.12 A.13 A.14 A.15 A.16 A.17 A.18 A.19 A.20 A.21 A.22 A.23 A.24 A.25 A.26 A.27 A.28 AT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 AT + BTCMODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 AT+BTDMODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 AT+BTPMODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 AT+BTSECMODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 AT+BTENCMODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 AT+BTPINCODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 AT+BTERASELK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 AT+BTNAME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 AT+BTCLASS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 AT+BTSETTINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 AT+BTINQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 AT+BTRPORTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 AT+BTREGPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 AT+BTMACROSTART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 AT+BTMACROSTOP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 AT+BTMACROCLEAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 AT+BTCONNECT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 AT+BTDISCONNECT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 AT+ECHO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 AT+UARTSETUP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 AT+UARTSETUP=? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 AT+VER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Appendix B AT event reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 B.1 8.2 B.2 B.3 B.4 B.5 +BTSETTINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 +BTRPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 +BTINQRES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 +UARTSETUP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 +VER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 +READY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Appendix C Application examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 3/32 Maximum ratings GS-BT2416C2.AT1 1 1.1 Maximum ratings Absolute maximum ratings Absolute maximum ratings (see table 2) indicate limits beyond which damage to the device may occur. Sustained exposure to these limits will adversely affect device reliability. Operating ranges (see table 3) define the limits for functional operation and parametric characteristics of the module. Functionality outside these limits is not implied Table 1. Symbol VDD VIN Tstg Tsold Absolute maximum ratings Values Parameter Min Module supply voltage Input voltage on any digital pin Storage temperature Soldering temperature Max 4 Vss1-0.5 Vdd+0.3 -40 +85 240 V V °C Unit 1.2 Operating ranges Table 2. Symbol VDD Tstg Operating ranges Values Parameter Module supply voltage Operating ambient temperature Conditions Min - 20°C < T < 70 °C 3.13 -20 Typ 3.3 Max 3.47 +70 V °C Unit 4/32 GS-BT2416C2.AT1 Electrical characteristics 2 2.1 Electrical characteristics DC I/O specification Table 3. Symbol Vil Vih Vhyst Vol Voh DC Input / Output specification Values Parameter Low level input voltage High level input voltage Schmitt trigger hysteresis Low level output voltage High level output voltage Conditions Min 3.13 V < VDD < 3.47 V 3.13 V < VDD < 3.47 V 3.13 V < VDD < 3.47 V Io load = pin drive capability Io load = pin drive capability VDD0.15 2 0.4 0.15 Typ Max 0.8 V V V V V Unit 3 Bluetooth section Table 4. Symbol CHs Hop 13M CK Bluetooth section Values Parameter Channel space Hopping System clock System clock stability - 20°C to 70°C - 20 32 - 200 200 721 432 90 50 Conditions Min Typ 1 1600 13 20 Max MHz Hops/ sec MHZ ppm kHz ppm kbits/ sec kbits/ sec mA mA Unit LP CK Low power clock Low power clock accuracy Tra Trs Transmission rate asynchronous Transmission rate synchronous Operation current TX mode Iop Operation RX mode 5/32 Bluetooth section GS-BT2416C2.AT1 3.1 RF performance characteristics In the performance characteristics table the following applies: ● Test condition: nominal – Voltage typical Vdd 3.3V – Temperature typical Tamb 25°C Parameters are given at antenna pin Table 5. Symbol Transmitter and receiver performance characteristics Parameter Conditions 2.402 GHz Min Typ 0 0 0 - 36 - 50 - 74 Max Unit dBm dBm dBm dBm dBm dBm TX Pout TX Output power 2.441 GHz 2.480 GHz ACP RX sens TX output spectrum adjacent channel power Receiver sensitivity lM-Nl = 2 lM-Nl ≥ 3 @BER 0.1% Table 6. Symbol RF in RF out TX out ∆F Synthesizer performance characteristics Parameter Input & Output frequency range TX output spectrum at -20 dB Bandwidth TX initial carrier frequency tolerance DH1 data packet - 75 Conditions Min 2402 920 Typ Max 2480 1000 75 25 40 40 20 Unit MHz kHz kHz kHz kHz kHz Hz l∆F –pn l TX carrier frequency drift DH3 data packet DH5 data packet l∆F/50µsl Drift rate 6/32 GS-BT2416C2.AT1 Integrate software 4 Integrate software The GS-BT2416C2.AT1 implements the following Bluetooth protocols and profiles: ● ● ● ● ● L2CAP RFCOMM SDP Generic Access Profile (GAP) Serial Port Profile (SPP) Operated through AT command interpreter. Figure 1. AT1 software implementation AT command interpreter SPP GAP RFCOMM L2CAP HCI FIRMWARE HCI Bottom Layer Bluetooth Protocols and Profiles SDP LINK MANAGER BASEBAND HW RF H W Hardware Layer 4.1 Features The module with AT1 implements all Bluetooth core protocols and Serial Port Profile (SPP) to replicate UART traffic over a Bluetooth link. 4.2 Command interface The module can be fully controlled using AT commands. The AT commands and few application examples are listed and commented in appendix A. 4.3 Usage scenarios The module with AT command is dedicated to implement serial cable replacement. An automatic point to point connection takes place when modules are switched on. Modules are configured via macro instruction to play the role of master or slave. 7/32 Application information GS-BT2416C2.AT1 5 Application information Here below there are some suggestions to better implement the module in the final application. ● Module is usually put on a motherboard, avoid that traces with switching signals are routed below the module. The best would be to have a ground plane underneath the module Connect the supply voltage ground of the module with the other grounds present on the motherboard in a star way. Keep the RF ground separate from the module supply voltage ground; the two grounds are already connected inside the module in one point, see below a possible implementation. Module foot print ● ● Figure 2. Module foot print Supply voltage GND RF gnd 8/32 GS-BT2416C2.AT1 Application information 5.1 Antenna reference RF output pin must be connected to an antenna which could be: ● ● ● Antenna directly printed on the pcb (Figure 3) Integrated antenna as, for example, Antenova 30-30-A5839-01 , Murata ANCV12G44SAA127, Pulse W3008 , Yageo CAN4311153002451K. (Figure 4) External antenna connected by means a SMA connector (Figure 5) Figure 4. Antenna examples Figure 5. SMA connector for external antenna Figure 3. Antenna on PCB ● Despite of the type of antenna chosen, the connection between the RF out pin and the antenna must be executed in such a way that the connection trace must be matched to have characteristic impedance (Z0) of 50 ohm to get the maximum power transfer. Matching for 50ohm is depending on the various factors , elements to be taken into consideration are: – – – – Type of material, i.e. FR4 The electrical characteristics of the material ,i.e. the εr , electric constant at 2.4GHz Mechanical dimensions of the pcb and traces ,i.e. pcb thickness , trace/ reference ground thickness, trace width , trace thickness Just to give an example , using a 1mm thick FR4 board , with an εr = 4.3 at 2.4GHz , with Cu thickness of 41 µm, the resulted width of 50ohm strip-line is 1.9 mm ( Microstrip type calculation). Parameters for trace matching ● Figure 6. Trace width Trace thickness PCB thickness εr (Dielectric constant) Reference ground Tools for calculating the characteristic impedance, based on the physical and mechanical characteristics of the pcb , can be easily found on the web. 9/32 Block diagram GS-BT2416C2.AT1 6 Block diagram Figure 7. Block diagram UART USB PCM SPI I²C GPIO 32kHz XTAL 32kHz XTAL RF antenna STLC2416 Baseband ARM7 proc STLC2150 Radio chip Filter balun 10/32 GS-BT2416C2.AT1 Pin settings 7 7.1 Pin settings Pin connections Figure 8. Pin connection diagram 7.2 Pin descriptions Table 7. Pin N° Pin descriptions Name I/O Description Power, ground and system signal 42 41 23 24 35 6 Vss1 Vdd RESET BOOT LP CLOCK OUT INT1 ----I I O I GND Module supply voltage- Single 3.3V Reset pin (active low) External downloading Enable (active low) internally pullupped to 1.8V by 10kohm 32kHz Out External Interrupt signal internally connected to VSS1 with 10K. / If not used connect to VSS1 General purpose signals 25 26 27 28 29 30 GPIO0 GPIO1 GPIO2 GPIO3 GPIO4 GPIO5 (1) General purpose I/O line Bluetooth link present General purpose I/O line Command/Data Mode Input General purpose I/O line General purpose I/O line O (1) I (1) (1) 11/32 Pin settings Table 7. Pin N° 31 32 33 34 36 37 38 39 40 GS-BT2416C2.AT1 Pin descriptions (continued) Name GPIO6 GPIO7 GPIO8 GPIO9 GPIO11 GPIO12 GPIO13 GPIO14 GPIO15 I/O (1) (1) (1) (1) (1) (1) (1) (1) (1) Description General purpose I/O line General purpose I/O line General purpose I/O line General purpose I/O line General purpose I/O line General purpose I/O line General purpose I/O line General purpose I/O line General purpose I/O line Test interface signals 1 4 2 3 5 TDI TDO TMS NTRST TCK (1) (1) (1) (1) (1) JTAG pin JTAG pin JTAG pin JTAG pin JTAG pin If not used connect to VSS1 I2C interface signals 7 8 I2C_dat I2C_clk (1) I2C bus interface data To be connected to VDD with 10 K. resistor I2C bus interface clock To be connected to VDD with 10 K. resistor (1) PCM interface signals 10 9 12 11 PCM_SYNC PCM_CLK PCM_A PCM_B (1) (1) (1) (1) PCM 8kHz synch PCM clock PCM Data In/Out PCM Data In//Out USB interface signals 21 22 USB_DN USB_DP (1) (1) USB data - If not used connect to VSS1 USB data + If not used connect to VSS1 UART interface signals 13 14 15 16 UART2_RXD UART2_TXD UART2_I1 UART2_02 I O I O UART2 data input If not used connect to VDD UART2 data output UART2 clear to send input If not used connect to VDD UART2 ready to send output 12/32 GS-BT2416C2.AT1 Table 7. Pin N° Pin settings Pin descriptions (continued) Name I/O Description SPI interface signals 17 18 19 20 Antenna signals 43 44 45 Vss2 ( RF GND) +ANTENNA Vss2 (RF GND) ------RF GND Antenna out RF GND SPI_FRM SPI_CLK SPI_TXD SPI_RXD (1) (1) (1) (1) Synchronous Serial Interface frame synch Synchronous Serial Interface clock Synchronous Serial Interface transmit data Synchronous Serial Interface receive data If not used connect to VSS1 1. Not used with AT command 13/32 Mechanical dimensions GS-BT2416C2.AT1 8 Mechanical dimensions Figure 9. Mechanical dimensions Figure 10. Land pattern and connection diagram 14/32 GS-BT2416C2.AT1 AT command Appendix A AT command SPP Embedded Bluetooth™ firmware for STLC2416 based modules version 1.2.1.8 A.1 Introduction AT command interpreter OBSTFW-101 has been developed by Sycom on its proprietary Bluetooth stack Following data are disclosed with Sycom permission and agreement. All these information are subject to usual ST reproduction and disclosure rules stated on the last page of the present document. 8.1 Description Sycom firmware OBSTFW-101, from now on named .AT1, implements all Bluetooth core protocols and Serial Port Profile (SPP) to replicate UART data traffic over a Bluetooth link. The module can be fully controlled using AT commands. The throughput over-the-air is up to ~290 Kbps. A.2 Modes of operation The module has two modes of operation: ● COMMAND MODE: this mode allows the module to accept AT commands from the UART. AT commands are used to control any property of the module (Bluetooth name, visibility, etc.) as well as to trigger any operation (connection set-up, tear-down, discovery, etc.) DATA MODE: this mode allows the module to send and receive raw data over a Bluetooth SPP link. When in DATA MODE each byte transmitted over the UART is replicated onto the existing Bluetooth SPP link, and each byte received from the remote Bluetooth device is replicated onto the UART port. DATA MODE should be activated only if a Bluetooth link has already been setup using AT commands in COMMAND MODE. ● To notice that there is not a default MODE, regardless connection status: this mean that the active MODE is always established by GPIO3 status. The external MCU can switch the mode of operation of the module using GPIO3. Both when the module is turned on or it is switched from DATA MODE to COMMAND MODE a +READY event is generated. This event informs the external MCU that the module is ready to accept AT commands. Before the +READY event is generated, no AT commands can be issued to the module. 15/32 AT command GS-BT2416C2.AT1 Moreover it is possible to store a startup commands sequence directly into flash memory. The sequence can be long up to 512bytes. If a macro sequence is present, in startup phase, some OK events are generated, one for every command of the sequence, before the +READY event. This behavior can be avoided setting a AT+ECHO=OFF command starting the macro (avoiding the +READY too). The sequence execution is stoppable changing the state of GPIO3 in startup phase. A.3 Interfaces The module must be controlled by an external MCU using the UART and 2 GPIOs. ● UART: used to control the module with AT commands (COMMAND MODE), or send/receive serial data to be transmitted over the SPP Bluetooth link (DATA MODE). The first time that the module is powered up, the default UART settings are as following (saved in flash memory): Baud rate: (bps) 9600 Data bits: 8 Parity: None Stop bits: 1 Flow control: None When these settings are changed by the AT+UARTSETUP command, they are stored in the flash memory to be reloaded when the module is powered up the next time. ● ● GPIO1: configured as output. GPIO1 is high when an SPP Bluetooth link to a remote device is present. GPIO1 is low when no Bluetooth link is present. GPIO3: configured as input. If GPIO3 is set to high the module switches its mode of operation to DATA MODE. If GPIO3 is set to low, the module switches its mode of operation to COMMAND MODE. 16/32 GS-BT2416C2.AT1 AT command A.4 Bluetooth features .AT1 implements the following Bluetooth protocols and profiles: ● ● ● ● ● L2CAP RFCOMM SDP Generic Access Profile (GAP) Serial Port Profile (SPP) The embedded SPP can be used in two modes: ● SERVER MODE: This mode allows the module to be connected by other devices. In this configuration the local module does not initiate a Bluetooth SPP connection, but simply exposes an SPP service that can be connected by other devices. In order to expose an SPP service the AT+BTREGPORT must be used. CLIENT MODE: This mode is used to initiate an SPP connection to an SPP service exposed by a remote Bluetooth device. To set-up an SPP Bluetooth link the AT+BTCONNECT must be used. ● The two modes of operation are fully interoperable and the same module can be configured simultaneously both as a CLIENT and SERVER device. The module only allows a single Bluetooth SPP connection to exist at the same time. When an active connection is present (GPIO1 high) the module is set as “Non-Connectable” and “Non-Discoverable”, to reduce affection of inquiry scan or connection entabishment attempt. When no more connection is active the module reset its modes to those previously stored by “+BTCMODE” and “+BTDMODE” commands. 17/32 AT command GS-BT2416C2.AT1 A.5 AT command reference AT commands are used to configure the module and trigger operations. AT commands are transmitted over the UART channel from the external MCU to the Bluetooth module. AT commands have the following syntax: AT + CMD = parameter0, parameter1, …\0x0D\0x0A AT + CMD\0x0D\0x0A Each line must be always terminated by the 0x0D 0x0A characters and only a single command per line is allowed. The response to an AT command can be OK if the command was successfully executed, or ERROR if an error occurred and has the following syntax: \0x0D\0x0AOK\0x0D\0x0A \0x0D\0x0AERROR\0x0D\0x0A Some AT commands can generate events. Events are always reported as follows: \0x0D\0x0A+EVENT: parameter0, …\0x0D\0x0A Each event is always bounded by the characters 0x0D 0x0A and can have zero or more parameters. The command syntax is case insensitive. A.6 AT Test the UART communication channel to the Bluetooth module Syntax: AT Return value: OK 18/32 GS-BT2416C2.AT1 AT command A.7 AT + BTCMODE Indicate if the module can be contacted by other Bluetooth devices. This command does not register any SPP service. Syntax: AT+BTCMODE= Parameters: 0: The module cannot be contacted by other Bluetooth devices (default) 1: The module can be contacted by other Bluetooth devices Return value: A.8 AT+BTDMODE Indicate if the module can be discovered when an inquiry procedure is performed by other Bluetooth devices. Syntax: AT+BTDMODE= Parameters: 0: The module cannot be discovered by other Bluetooth devices (default) 1: The module can be discovered by other Bluetooth devices Return value: