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An Introduction to the Silicon Labs BT121 Bluetooth Long Range Smart Ready Module and DKBT Development Kit

Wednesday, May 13, 2015

The Silicon Labs BT121 Long Range BT 4.1 Smart Ready Module integrates both Bluetooth BR/EDR and Bluetooth Smart wireless technologies in a single 11x14mm module with an integrated antenna and fully certified dual mode protocol stack, minimizing design time, cost, and complexity. It is ideal for applications that require connectivity to both legacy devices that only support Bluetooth BR/EDR and newer devices that support Bluetooth Smart including connected home, health and fitness, wearables, and point-of-sale terminals. The BT121 has uncompromising performance with RF output up to +12 dBm, providing reliable and long range Bluetooth connections, and is certified with full modular approval for FCC, IC, CE, South Korea, and Japan.


BT121 integrates a high performance Bluetooth radio, a low-power ARM Cortex microcontroller, and a Bluegiga Bluetooth Smart Ready stack software, making it extremely easy to use as no RF or Bluetooth software development is needed, and provides connectivity to Windows, Android, and Apple devices. BT121 can be used as a modem together with a separate host MCU, but applications can also be embedded into the built-in ARM Cortex MCU with the Bluegiga BGScriptTM scripting language.



The Apple MFI version of the module, the BT121-A-V1-IAP, provides support for the Apple iAP2 Accessory Protocol (Apple MFI license required).


BT121 Features:  

  • Bluetoothv.4.1 dual mode:
  •  - Supports master and slave modesuctorstore.c
  •  - Up to 6 x BR/EDR and 7 x BLE connections
  •  - 1x BR/EDR + 7 x BLE connections
  • Radio Performance:
  •  - Transmit power: +10 (BLE) / 12 dBm (BR/EDR)
  •  - Receiver sensitivity: -96 dBm
  •  - Link budget 106 dB
  •  - Range 200-400 meters
  • Low Current Consumption:
  •  - Full EDR transmit55 mA
  •  - BLE connected 170 uA
  •  - Power mode 2 60 uA
  •  - Power mode 2, radio OFF7uA*
  •  - Sleep with RTC wake-up3 uA*
  • Integrated Bluetooth Smart Ready stack:
  •  - SPP, iAP2 for Bluetooth Classic
  •  - GATT over BR
  •  - Common GAP, SMP and L2CAP
  •  - ATT and GATT for Bluetooth Smart
  •  - Any Bluetooth Smart profile(s)
  • Flexible Peripheral Interfaces:
  •  - UART, SPI and I2C serial interfaces
  •  - PWM*,GPIO with interrupts
  •  - 12-bit ADC and DAC
  • Host Interfaces:
  •  - UART
  • Compact Size:
  •  - 11.0 mm x 13.9 mm x 2.2 mm
  •  - 153 mm2
  • RTC with calendar alarms*
  • Programmable ARM Cortex-M0 processor:
  •  - 16kb RAM / 256 kB Flash
  • Bluetooth, CE, FCC, IC, South-Korea and Japan qualified

*Apple MFI license required


The DKBT BT121 Long Range Bluetooth 4.1 Smart Module Development Kit contains everything needed to jumpstart a Bluetooth Smart Ready design using the BT121 module.



The DKBT Development Kit Contains:

  • Display
  • On-board accelerometer, altimeter and potentiometer
  • AAA battery holder
  • USB and RS232 interfaces
  • On-board firmware programming
  • Current measurement point
  • I/O headers
  • BT121 Carrier Board
  • Bluetooth Smart Ready SDK:
  •  - BGAPITM documentation
  •  - BGScriptTM development tools
  •  - BGLIBTM source code
  •  - Profile ToolkitTM 
  •  - BGScript and BGLIB examples
  •  - Profile examples
  • Documentation
  • iOS and Android example applications for BLE


The BLE121LR is a similar long range module, but only supports Bluetooth Smart. This is a good option when classic Bluetooth is not required.


Order yours, or get more information about BT121 and other Silicon Labs products by calling Symmetry at (310) 536-6190, or contact us online.



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