BT121 BLUETOOTH SMART READY MODULE DATA SHEET Tuesday, 09 June 2015 Document Version: 1.
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VERSION HISTORY Date Edited Comment 1.0 First release of document 1.1 Minor updates 1.2 Minor updates 1.3 Power consumption measurements 1.4 Revised power consumption measurements 1.
TABLE OF CONTENTS BT121 overview 6 1.1 Key Features 6 1.2 Typical applications 7 1.3 Block diagram 7 Design guidelines 8 2.1 PCB layout recommendations 8 2.2 Power supply recommendations 8 2.3 Software application related options 8 2.4 Firmware updating related recommendations 8 Pin-out description 10 3.1 Power, ground, reset, RF and boot loader pins 10 3.2 GPIO pins 11 Power control 12 4.1 Power supply requirements 12 4.2 Power saving functionality 12 4.
8.1 UART 26 Connection examples 27 9.1 Connecting an external host using the UART interface 27 9.2 Connecting an external device using SPI interface 28 9.3 Connecting an external device using I2C interface 29 Electrical characteristics 30 10.1 Absolute maximum ratings 30 10.2 Recommended operating conditions 30 10.3 Logic signal characteristics 31 RF Characteristics 33 11.1 Supported frequencies and channels 35 11.2 Typical receiver sensitivity 35 11.
BT121 overview BT121 is a Bluetooth Smart Ready module targeted for applications that require both Bluetooth Smart and Classic connectivity. It can connect to legacy devices that only support Bluetooth SPP or Apple ® iAP2 profiles as well to devices that support Bluetooth Smart. BT121 integrates a high performance Bluetooth radio, a lowpower ARM Cortex micro-controller and a Bluegiga Bluetooth Smart Ready stack software marking it extremely easy-to-use as no RF or Bluetooth software development is needed.
1.2 Typical applications BT121 can be used in a wide variety of applications such as health and fitness, PoS (point-of-sales), M2M connectivity, automotive aftermarket, industrial and home automation gateways and others. 1.3 Block diagram The block diagram for Bluegiga Bluetooth Smart Ready module BT121 is shown in below.
Design guidelines Certain hardware related design guidelines should always be followed when developing applications based on the BT121 module. 2.1 PCB layout recommendations All ground pads should be connected to a ground plane. The antenna layout should follow the example shown in Figure 2 below and avoid the designs shown as crossed over.
Figure 3 BT121 firmware update via UART connection example Bluegiga – A Silicon Labs Company 9
Pin-out description This section contains a description of the BT121 pin-out. Each pin may have one or more functions which are all listed in tables. The pin-out is shown in Figure 4 below. Figure 4 BT121 pin-out (top view) 3.1 Power, ground, reset, RF and boot loader pins Power supply, ground, reset signal, RF antenna input/output and boot loader related pins are listed in Table 1 below. Pin / Pad Function 30,34 VDD Module power supply input pins. 1, 2, 3, 13, 21, 31, 32, 33, 41 GND Ground pin.
3.2 GPIO pins General purpose I/O pins and their functions are listed below.
Power control 4.1 Power supply requirements BT121 is powered by a single power supply input (VDD). Nominal input voltage is 3.3 VDC and input voltage range 2.2 V to 3.6 V. If the module’s internal ADC and/or DAC functions are used minimum allowed power supply voltage is 2.4V. The VDD supply should be capable of supplying a peak current of at least 150 mA even though the average current consumption of BT121 will be much less than that.
Power mode CPU clocks CPU core Radio Wakeup delay UART Current consumption * Active ON Running On - Active 10 - 20 mA Power mode 1 ON Stopped On < 7μs Active 4 - 10 mA Power mode 2 OFF Powered off On < 70 μs Off 50 - 100 μA Table 3 Power modes with corresponding wakeup delays and current consumption * Current consumption with radio inactive The logic flow of the power saving modes in relation to each other is shown in Figure 5 below.
4.4 Recovery mode Pulling the BOOT0 pin high at reset sets the BT121 module’s internal microcontroller into a recovery mode, which allows the Bluegiga DFU to be rewritten to the module using the DumoGUI software. The BOOT0 pin should be connected to a header or test point to enable DFU recovery. The pin is internally connected to a 10 kohm pull-down resistor. 4.5 Clock signals BT121 generates all the required clock signals internally.
Interfaces 5.1 GPIO BT121 contains a number of pins which can be configured to operate as general purpose digital I/O’s, analog inputs or outputs or to be used in combination with various built-in functions. The module contains I2C, SPI, UART, touch pad sensing and various timer functions. Most of the pins are 5V tolerant. All GPIO pins can drive currents of up to +/- 8 mA (up to 20mA with relaxed voltage specifications). 5.1.1 GPIO interrupts Any GPIO signal can be assigned an interrupt function.
5.2 UART There is one UART port available on the BT121. By default it is used for BGAPI™ host interface but with BGScript™ it can be used as an application UART. The UART supports all standard baud rates up to 4 Mbps. RTS/CTS handshake scheme is supported and recommended for every application for reliable data transfer. 5.3 I2C BT121 has up to two I2C ports available.
Antenna The internal chip antenna on the BT121 uses the application board ground plane as part of the antenna, and requires at least 20 mm of ground plane on both sides of the module to radiate with optimal efficiency. BT121 must be placed on the application board edge, preferably roughly in the middle of the board edge. The ground plane can be internal to the application PCB, allowing components to be placed on both sides of the module and on both sides of the application board.
6.1 Effect on antenna matching of a plastic sheet placed near the antenna As an example on how a plastic sheet placed in the vicinity of the module and/or antenna effect the antenna matching we can examine Figure 8 below.
6.2 Effect on antenna matching of a metal sheet placed under the antenna As an example on how a metal sheet placed in the vicinity of the module and/or antenna effect the antenna matching we can examine Figure 9 below.
6.3 Effect on antenna matching of a metal sheet placed against the end of the module As an example on how a metal sheet placed in the vicinity of the module and/or antenna effect the antenna matching we can examine Figure 10 below.
6.4 Measured antenna efficiency The measured antenna efficiency as a function of frequency is shown in Figure 11 below.
6.5 Measured 2D radiation patterns Typical radiation patters of the BT121 module shown as 2D plots are shown below in Figure 12 (view from module side), Figure 13 (view from antenna end) and on the following page in Figure 14 (view from above module).
Figure 14 Typical 2D radiation pattern for BT121 with view from above module Bluegiga – A Silicon Labs Company 23
6.6 Measured 3D radiation patterns Typical radiation patters of the BT121 module shown as 3D plots are shown below. Figure 15 represents a radiation pattern from module end side opposite to antenna and Figure 16 from above the module.
Bluetooth Stack Software Bluegiga's Bluetooth Smart Ready Software is a complete Bluetooth Smart Ready software stack for BT121 Bluetooth Smart Ready module. The software implements a full Bluetooth BR/EDR and LE compatible Bluetooth Stack and L2CAP, RFCOMM, SMP and ATT protocols as well as Bluetooth SPP, Apple iAP2, GATT over BT profiles and any GATT based Bluetooth Smart profile.
Host interface 8.1 UART For applications where an external host such as MCU is used BT121 can be controlled over the UART interface using the BGAPITM serial protocol. For reliable communications can data transfer the hardware flow control RTS/CTS signals must be used in the UART interface. It is also recommended that the accuracy of the clock of the controlling host should be 1% or better for the UART signaling to work reliably with speeds exceeding 115200 kbps (maximum baud rate is 4 Mbps).
Connection examples The following sections show how to connect a Bluegiga Bluetooth Smart Ready module with various external devices using the UART, SPI and I2C interface. 9.1 Connecting an external host using the UART interface The connection to an external host is done using the UART interface of the module. This interface is also used for module reprogramming using the DFU method and thus an optional connector should be provided on the application PCB to allow reprogramming if needed.
9.2 Connecting an external device using SPI interface Bluegiga Bluetooth Smart Ready module BT121 contains two physical SPI peripherals (SPI 1 and SPI2) each with alternative configurations (Alt 1 and Alt 2). All of the four optional configurations can be used to connect different types of peripheral devices to the module. Pin configurations for the four SPI interface options are listed in Table 2. An example of this type of interfacing is shown in Figure 19 below.
9.3 Connecting an external device using I2C interface Bluegiga Bluetooth Smart Ready module BT121 contains two physical I2C peripherals (I2C 1 and I2C 2). I2C 1 has two alternatives (Alt 1 and Alt 2) and I2C 2 one alternative (Alt 2). All of the three optional configurations can be used to connect different types of peripheral devices with the module. Pin configurations for the three I2C interface options are listed in Table 2. An example of this type of interfacing is shown in Figure 20 below.
Electrical characteristics 10.1 Absolute maximum ratings Parameter Min Max Unit Storage temperature -40 85 °C VDD -0.3 3.6 V 5V tolerant GPIO voltages -0.3 5.5 V Other terminal voltages -0.3 VDD+0.3 V Output current sourced or sunk by any GPIO pad 25 mA Current on all GPIO pads combined 120 mA Table 5 Absolute maximum ratings 10.2 Recommended operating conditions Rating Min Max Unit Operating temperature range -40 85 °C VDD 2.2 3.6 V VDD (when operating ADC or DAC) 2.
10.3 Logic signal characteristics 10.3.1 Digital I/O Digital I/O pins Min Typ Max Unit VIL input logic level low 1.7V ≤ VDD ≤ 3.6V -0.3 - 0.3VDD V VIH input logic level high 1.7V ≤ VDD ≤ 3.6V 0.7 VDD - VDD + 0.3 V - - 0.4 V VDD - 0.4 - VDD V Input voltage levels Output voltage levels VOL output logic level low, Vdd = 3.6 V, Iol = 7 mA VOH output logic level high Vdd = 3.6 V, Ioh = -12 mA Table 7 Digital I/O pin electrical characteristics 10.3.
10.3.4 DAC Power-on Reset Min Typ Max Unit 5 - - kohm 0.2 - VDD - 0.2 V DAC differential nonlinearity - - 2 LSB DAC integral nonlinearity - - 4 LSB DAC offset error - - 12 LSB DAC gain error - - 0.
10.4 Power consumption Operation state Current Unit CPU active 14 mA Power state 1 - RF idle 6.
Connected, continuous data 15.8 mA 115kbps over BGAPI* Connected, continuous data, sniff 1s 7.2 mA 115kbps over BGAPI* Table 13 Typical power consumption, Classic Bluetooth (Master mode, CPU sleep enabled) *sleep controlled by wakeup pin, in the constant UART data streaming test the CPU is not allowed to enter sleep mode Operation state Current Unit Description Advertising, not connectable 1.4 mA 108ms Advertising, connectable 1.
RF Characteristics 11.1 Supported frequencies and channels Parameter Min Max Unit Frequency 2402 2480 MHz Channels 0 78 CH # Table 15 Supported frequencies and channels 11.2 Typical receiver sensitivity -40 to 85oC Unit DH1 -95 dBm 2DH1 -96 dBm 3DH3 -88 dBm LE -96 dBm Packet type Table 16 Typical receiver sensitivity 11.
Physical dimensions Figure 21 BT121 module physical dimensions Figure 22 BT121 module recommended PCB pad pattern The 8 center pins of the module are reserved for production programming and should be left unsoldered but despite of this unmasked traces and vias should NOT be placed under the module in order to prevent short circuits.
Figure 23 BT121 module side view dimensions Bluegiga – A Silicon Labs Company 37
Soldering recommendations Bluegiga Bluetooth Smart Ready module BT121 is compatible with the industrial standard reflow profile for Pb-free solders. The reflow profile to be used depends on the thermal mass of the entire populated application PCB, heat transfer efficiency of the oven and on the particular type of solder paste used. Consult the datasheet of the particular solder paste used for more detailed information regarding profile configurations.
13.1 Soldering profile example As an example of a typical soldering profile please see an example of a generic example of a reflow profile shown below. As stated in previous section soldering profiles are solder paste specific. Consult the manufacturer of the paste used.
Tape and reel packaging This section contains information regarding the tape and reel packaging and materials of packaging with dimensions for the Bluegiga Bluetooth Smart Ready BT121 module. 14.1 Reel material and dimensions Reel material Reel diameter Reel color PS Conductive Black – surface resistance 103 ↔ 105 13” Black Symbol Dimensions [mm] D0 330.2 D1 100.0 W1 24.0 Table 19 Reel dimensions 14.
14.3 Tape and reel box dimensions Symbol Dimensions [mm] W1 338 W2 344 W3 44 Table 21 Tape and reel box dimensions 14.
Certifications BT121 compliance certifications are pending. 15.1 CE BT121 is in conformity with the essential requirements and other relevant requirements of the R&TTE Directive (1999/5/EC). The product is conformity with the following standards and/or normative documents. EMC (immunity only) EN 301 489-17 V.1.3.2 in accordance with EN 301 489-1 V1.8.1 Radiated emissions EN 300 328 V1.8.1 15.2 FCC This device complies with Part 15 of the FCC Rules.
IMPORTANT NOTE: In the event that these conditions cannot be met (for certain configurations or co-location with another transmitter), then the FCC authorization is no longer considered valid and the FCC ID cannot be used on the final product. In these circumstances, the OEM integrator will be responsible for re-evaluating the end product (including the transmitter) and obtaining a separate FCC and Industry Canada authorization. End Product Labeling The BT121 module is labeled with its own FCC ID.
Ordering information Product code Description BT121-A-V1 BT121 Bluetooth Smart Ready module with an integrated antenna BT121-A-V1-iAP BT121 Bluetooth Smart Ready module with an integrated antenna and Apple iAP profile. This part number is only available to Apple MFI licenses.
Contact Information Sales: www.bluegiga.com Technical Support: www.bluegiga.com/support Orders: bluegiga-orders@silabs.com WWW: www.bluegiga.com SILICON LABS Phone: +1 877.444.
