4.15  UART
STWBC2 is intended to be operated independently that is, without being interfaced with a host system. For 
development purposes, there might be a need to access the device for the runtime diagnostics and configuration. 
This is done primarily by the STSW-WBC2STUDIO software, which is described in Section 5: Graphical user 
interface (GUI) of this document.
For the purpose of mass production, the user may either use the STM32Cube Programmer, or implement the 
UART approach described in the following chapters to program the devices.
In case of STLINK usage, its UART interface is used, but any generic UART (supporting the configuration 
described later) can be used as well.
Note: It is necessary to manually calibrate the device after the first power-up.
4.15.1  UART configuration
Rate: 115200 bps
Data bits: 8 b
Parity: None
Stop bits: 1 b
4.15.2  Firmware update without GUI
This approach aims to simplify mass production by automating the device loading. UART commands are used for 
programming.
For already loaded devices, it is necessary to switch to a bootloader mode first. Empty devices switch to the 
bootloader mode automatically.
When in bootloader mode, the NVM can be erased and loaded. The bootloader and its use are described in detail 
in the USART protocol used in the STM32 bootloader application note for STM32 microcontrollers.
Figure 13. Bootloader start
UM3286
Device description and operation
UM3286 - Rev 1
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