Core Module

The Core Module is the key element of every BigClown node. It has a 32-bit ARM microcontroller with 192 kB of flash memory and 20 kB of RAM. Besides the integrated sub-GHz radio for the 868/915 MHz band, it also features a digital temperature sensor, 3D accelerometer, and security chip.

Core Module R2 is the new revision. It has added FTDI FT231XQ chip which allows faster flashing and no need to press buttons for DFU mode. This FTDI chip is acting as a USB to UART bridge and is connected to UART2. This way you can use it during debugging or logging using the bc_log_* functions.

You can upload firmware by a Micro USB cable using the BigClown Firmware Tool (works on Windows, macOS, and Linux). It is easy to start development on this platform using the BigClown Firmware SDK (Software Development Kit). The SDK offers clean and consistent APIs which allow event-driven programming. These APIs are designed for low-power and battery-operated applications. If you need to debug your application and the logging API is not sufficient, you can use an SWD debugger and the onboard 10-pin connector.

The Core Module can communicate wirelessly with another Core Module, or you can create your wireless network using the Radio Dongle.


  • ARM Cortex M0+ 32-bit MCU STM32L083CZ (ST)
  • 192 kB Flash / 20 kB RAM
  • Radio module (868/915 MHz) based on SPIRIT1 (ST)
  • Security chip ATSHA204A (Microchip)
  • Digital temperature sensor TMP112 (TI)
  • 3-axis accelerometer LIS2DH12 (ST)
  • Red color LED
  • Push button RESET and BOOT (BOOT is available to MCU)
  • Easily programmable via USB (DFU bootloader)
  • 10-pin SWD connector for debugging
  • Micro-USB for host communication and/or power
  • 18x GPIO (completely free for application)
  • 3x UART, 2x I²C, 1x SPI, 5x ADC, 2x DAC
  • Deep sleep mode: < 5 µA
  • Operating voltage range: 2.0 V to 3.6 V
  • Operating temperature range: -20 to 70 °C
  • Mechanical dimensions: 33 x 55 mm


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