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.

GPIO Pin Mapping

Table below explains mapping between pin numbers and real STM32L083CZ GPIO pin names:

Pin Signal MCU Pin 5 V tolerant
1 P0/A0/TXD0 PA0 (10) -
2 P1/A1/RXD0 PA1 (11) Yes
4 P3/A3/RXD1 PA3 (13) Yes
3 P2/A2/TXD1 PA2 (12) Yes
5 P4/A4/DAC0 PA4 (14) -
6 P5/A5/DAC1 PA5 (15) -
7 P6/RTS1 PB1 (19) Yes
8 P7/CTS1 PA6 (16) Yes
9 P8 PB0 (18) Yes
10 P9 PB2 (20) Yes
21 P10/RXD2 PA10 (31) Yes
22 P11/TXD2 PA9 (30) Yes
23 P12/MISO PB14 (27) Yes
24 P13/MOSI PB15 (28) Yes
25 P14/SCLK PB13 (26) Yes
26 P15/CS PB12 (25) Yes
27 P16/SCL1 PB8 (45) Yes
28 P17/SDA1 PB9 (46) Yes
  • Maximum current for a single pin is 16 mA.
  • Maximum current fo all GPIOs combined is 90 mA.


  • 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


Firmware Projects

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