GS-BT2416C1AT1

GS-BT2416C1.AT1 Bluetooth® class 1 module with embedded SPP SW Features ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Bluetooth® specification V.1.2 compliant Transmission rate up to 721 Kbps Output power class 1 (20 dBm max) Working distance up to 100 meters ACL and SCO links AFH interference 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 4 Mbit Flash, 64 Kbytes RAM, 4 Kbytes ROM 3.3 V single supply voltage Hardware based UART flow control Description Applications ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Serial cable replacement Industrial control Laptops POS terminals Data acquisition equipment Internet access points Machine control Sensor monitoring Security control Robotic and bionic 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...) bs O let o Pr e du o (s) ct so Ob - ST Bluetooth® modules are highly integrated for easy implementation in embedded applications. Class 1 modules enable wireless communication with other Bluetooth® enabled devices up to 100 m away. The GS-BT2416C1.AT1 integrates on a unique FR4 PCB support: BT 1.2 radio and baseband, memory, 32 kHz and 13 MHz oscillator, Vreg as well PA function. 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-BT2416C1DBAT1 application note. The GS-BT2416C1.AT1 is the SPP with AT command module of the GS-BT2416C1.xx series. GS-BT2416C1.AT1 is BQB pre-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. te le ro P uc d s) t( May 2008 Rev 2 1/38 www.st.com 38 Contents GS-BT2416C1.AT1 Contents 1 2 Certifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1 2.2 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Operating ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.1 DC I/O specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4 Bluetooth® section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.1 RF performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5 Integrate software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.1 5.2 5.3 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Command interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Usage scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 6.1 Antenna reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 7 8 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 8.1 8.2 bs O 10 9 let o Soldering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Mechanical dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Pr e Pin connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 du o (s) ct so Ob - te le ro P uc d s) t( Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2/38 GS-BT2416C1.AT1 Contents Appendix A AT command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 A.1 10.1 A.2 A.3 A.4 A.5 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 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Modes of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Interfaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Bluetooth® features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 AT command reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 AT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 AT + BTCMODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 AT+BTDMODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 AT+BTPMODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 AT+BTSECMODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 AT+BTENCMODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 AT+BTPINCODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 AT+BTERASELK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 AT+BTNAME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 AT+BTCLASS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 AT+BTSETTINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 AT+BTINQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 AT+BTRPORTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 AT+BTREGPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 AT+BTMACROSTART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 AT+BTMACROSTOP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 AT+BTMACROCLEAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 AT+BTCONNECT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 AT+BTDISCONNECT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 AT+ECHO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 AT+UARTSETUP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 AT+UARTSETUP=? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 AT+VER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 bs O let o A.24 A.25 A.26 A.27 Pr e du o (s) ct so Ob - te le ro P uc d s) t( A.28 3/38 Contents GS-BT2416C1.AT1 Appendix B AT event reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 B.1 10.2 B.2 B.3 B.4 B.5 +BTSETTINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 +BTRPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 +BTINQRES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 +UARTSETUP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 +VER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 +READY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Appendix C Application examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 11 12 Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 bs O let o Pr e du o (s) ct so Ob - te le ro P uc d s) t( 4/38 GS-BT2416C1.AT1 Certifications 1 Certifications ● CE compliant (IMQ exp. opinion 0081-AREF00017) – – – – – Safety EN60950-1 (2001) EMC EN301 489 17V1.2.1 Radio ES 300 328 V1.6. FCC certified on GS-BT2416C1DBAT1 (for a more exhaustive explanation, please refer to GS-BT2416C1DBAT1 application note) FCC ID: S9NBT2416C1DB ● BQB compliant bs O let o Pr e du o (s) ct so Ob - te le ro P uc d s) t( 5/38 Maximum ratings GS-BT2416C1.AT1 2 2.1 Maximum ratings Absolute maximum ratings Absolute maximum ratings (see Table 1) indicate limits beyond which damage to the device may occur. Sustained exposure to these limits will adversely affect device reliability. Operating ranges (see Table 2) 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 V Unit 2.2 Operating ranges Table 2. Symbol VDD Tstg Operating ranges Parameter Module supply voltage Operating ambient temperature bs O let o od Pr e ct u (s) Ob - Conditions so te le ro P Min 3.13 -20 uc d 240 Typ 3.3 s) t( V °C Values Unit Max 3.47 +70 V °C - 20 °C < T < 70 °C 6/38 GS-BT2416C1.AT1 Electrical characteristics 3 3.1 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 4 Bluetooth® section Table 4. Symbol CHs Hop 13M CK Bluetooth® section Parameter Channel space Hopping System clock LP CK bs O let o Pr e Tra Trs Iop System clock stability Low power clock Low power clock accuracy Transmission rate asynchronous Transmission rate synchronous Operation current TX mode Operation RX mode du o (s) ct so Ob - te le ro P Min uc d s) t( Values Unit Typ 1 1600 13 Max MHz Hops/ sec MHZ 20 32 - 200 200 721 432 180 60 ppm Conditions - 20 °C to 70 °C - 20 kHz ppm kbits/ sec kbits/ sec mA mA 7/38 Bluetooth® section GS-BT2416C1.AT1 4.1 RF performance characteristics In the performance characteristics table the following applies: ● Test condition: nominal – Voltage typical Vdd = 3.3 V – Temperature typical TA = 25 °C Parameters are given at antenna pin Table 5. Symbol Transmitter and receiver performance characteristics Parameter Conditions 2.402 GHz Min Typ 18 18 18 - 36 - 44 - 84 Max 20 20 20 Unit 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 and output frequency range TX output spectrum at -20 dB Bandwidth TX initial carrier frequency tolerance Conditions l∆F –pn l TX carrier frequency drift bs O let o l∆F/50µsl ro P e uc d (s) t so Ob - eP let Min 2402 - 75 od r Typ 920 uc s) t( dBm Max 2480 1000 75 25 40 40 20 Unit MHz kHz kHz kHz kHz kHz Hz DH1 data packet DH3 data packet DH5 data packet Drift rate 8/38 GS-BT2416C1.AT1 Integrate software 5 Integrate software The GS-BT2416C1.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 Hardware Layer 5.1 Features The module with AT1 implements all Bluetooth® core protocols and serial port profile (SPP) to replicate UART traffic over a Bluetooth® link. 5.2 Command interface bs O 5.3 let o The module can be fully controlled using AT commands. The AT commands and few application examples are listed and commented in appendix A. Pr e du o (s) ct so Ob - RF H W te le ro P uc d s) t( 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. 9/38 Application information GS-BT2416C1.AT1 6 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 bs O let o Pr e du o (s) ct so Ob - te le ro P uc d s) t( 10/38 GS-BT2416C1.AT1 Application information 6.1 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 Ω to get the maximum power transfer. Matching for 50 Ω 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 2.4 GHz 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 1 mm thick FR4 board, with an εr = 4.3 at 2.4 GHz, with Cu thickness of 41 µm, the resulted width of 50 Ω strip-line is 1.9 mm (Microstrip type calculation). Parameters for trace matching ● Figure 6. bs O let o Trace width Pr e du o (s) ct so Ob - te le ro P uc d s) t( 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. 11/38 Block diagram GS-BT2416C1.AT1 7 Block diagram Figure 7. Block diagram RF antenna UART USB PCM SPI I²C GPIO STLC2416 Baseband ARM7 proc STLC2150 Radio chip LNA PA SW Filter 32kHz XTAL 32kHz XTAL bs O let o Pr e du o (s) ct so Ob - te le ro P uc d s) t( 12/38 GS-BT2416C1.AT1 Pin settings 8 8.1 Pin settings Pin connections Figure 8. Pin connection diagram bs O let o Pr e du o (s) ct so Ob - te le ro P uc d s) t( 13/38 Pin settings GS-BT2416C1.AT1 8.2 Table 7. Pin N° Pin descriptions Pin descriptions Name I/O Description Power, ground and system signal 1 2 41 42 43 44 45 46 13 26 Vss1 Vdd 1V8 3V3 Vss1 2V7 RESET BOOT LP CLOCK OUT INT1 ----O O --O I I O (1) GND Module supply voltage - single 3.3 V 1.8 V digital supply out (test purpose) to be left not connected 3.3 V I/O power supply out (test purpose) to be left not connected GND (test purpose) to be left not connected 2.7 digital core supply out (test purpose) to be left not connected Reset pin (active low) External downloading enable (active low) internally pull-upped to 1.8 V by 10 kΩ 32 kHz out External interrupt signal internally connected to VSS1 with 10 kΩ / if not used connect to VSS1 General purpose signals 3 4 5 6 7 8 10 11 12 14 GPIO0 GPIO1 GPIO2 GPIO3 GPIO4 GPIO5 GPIO7 GPIO8 GPIO9 (1) General purpose I/O line I (1) Bluetooth® link present General purpose I/O line I (1) (1) (1) (1) (1) (1) Command/data mode input General purpose I/O line General purpose I/O line General purpose I/O line General purpose I/O line GPIO11 No connect signals 9 O bs 15 16 17 18 let o ---------------- Pr e du o (s) ct so Ob - te le ro P uc d s) t( General purpose I/O line General purpose I/O line (1) (1) (1) (1) (1) Not to be used internally used for RX/TX switch Not to be used internally used for TX gain setting Not to be used internally used for TX gain setting Not to be used internally used for TX gain setting Not to be used internally used for TX gain setting 14/38 GS-BT2416C1.AT1 Table 7. Pin N° Pin settings Pin descriptions (continued) Name I/O Description Test interface signals 19 20 21 22 23 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 24 25 I2C_dat I2C_clk (1) (1) I2C bus interface data to be connected to VDD with 10 kΩ resistor I2C bus interface clock to be connected to VDD with 10 kΩ resistor PCM interface signals 27 28 29 30 PCM_SYNC PCM_CLK PCM_A PCM_B (1) (1) (1) (1) PCM 8 kHz synch PCM clock PCM data in/out PCM data in//out USB interface signals 31 32 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 33 34 35 36 47 48 UART2_RXD UART2_TXD UART2_I1 UART2_02 UART10_TXD 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 UART1 data output UART1 data input If not used connect to VDD (1) (1) UART11_RXD SPI interface signals 37 O bs 38 39 40 49 50 51 let o SPI_FRM SPI_CLK Pr e du o (s) ct so Ob - te le ro P uc d s) t( (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 SPI_TXD SPI_RXD Antenna signals Vss2 (RF GND) +ANTENNA Vss2 (RF GND) ------RF GND Antenna out RF GND 1. Not used with AT command 15/38 Soldering GS-BT2416C1.AT1 9 Soldering Soldering phase has to be execute with care: in order to avoid undesired melting phenomenon, particular attention has to be take on the set up of the peak temperature. Here following some suggestions for the temperature profile based on IPC/JEDEC J-STD-020C, July 2004 recommendations. Table 8. Soldering Profile feature Average ramp up rate (TSMAX to TP) Preheat Temperature min (TS min) Temperature max (TS max) Time (tS min to tS max) (tS) Time maintained above: Temperature TL Time tL Peak temperature (Tp) Time within 5 °C of actual peak temperature (tP) Ramp down rate Time from 25 °C to peak temperature PB free assembly 3 °C / sec max 150 °C 200 °C 60 – 100 sec 217 °C 40 – 70 sec Figure 9. Soldering bs O let o Pr e du o (s) ct so Ob - te le ro P 240 + 0 °C 10 – 20 sec 6 °C / sec uc d s) t( 8 minutes max 16/38 GS-BT2416C1.AT1 Mechanical dimensions 10 Mechanical dimensions In order to meet environmental requirements, ST offers these devices in ECOPACK® packages. These packages have a lead-free second level interconnect. The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com. Figure 10. Mechanical dimensions bs O let o Pr e du o (s) ct so Ob - te le ro P uc d s) t( 17/38 Mechanical dimensions Figure 11. Land pattern and connection diagram GS-BT2416C1.AT1 bs O let o Pr e du o (s) ct so Ob - te le ro P uc d s) t( 18/38 GS-BT2416C1.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. 10.1 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. ● O bs let o 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. Pr e du o (s) ct so Ob - te le ro P uc d s) t( ® 19/38 AT command GS-BT2416C1.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. bs O let o Pr e du o (s) ct so Ob - te le ro P uc d s) t( 20/38 GS-BT2416C1.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 establishment attempt. When no more connection is active the module reset its modes to those previously stored by “+BTCMODE” and “+BTDMODE” commands. bs O let o Pr e du o (s) ct so Ob - te le ro P uc d s) t( 21/38 AT command GS-BT2416C1.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 bs O let o Pr e Return value: OK du o (s) ct so Ob - te le ro P uc d s) t( 22/38 GS-BT2416C1.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: