Answer

Introduction 

 Lyra BGM220P, BGM220S modules from BG22 family can be programmed with two bootloaders types:

•  BGAPI UART DFU – programmed by SiLabs to all BG22 modules, supports firmware updates over UART with special utility uart_dfu.exe 

 UART XMODEM – the firmware update can be performed over UART interface using TeraTerm or similar program, the protocol for sending the file is XMODEM 

 The instructions below will provide with steps for building, and debugging the bootloader firmware using Simplicity Studio.  

Building

The bootloader project is built by right clicking the project in the Project Explorer and selecting “Build Project”. The project built takes several minutes and should complete without errors or warnings. The information on the progress of the building process is outputted to the Console. The output of the building process is a file in binary format 
 

Debugging  

The firmware is debugged with Simplicity Studio debug perspective. The bootloader executable, which includes debugging symbols and was produced by project build is loaded by debug session J-Link utility during launch to the internal flash of the module into location 0x00. Once the firmware is loaded to the flash the debug session will instruct the MCU to run the firmware from the Reset vector location. The debug session is configured to halt the MCU at main() and can be resumed by pressing "Resume" button within debug perspective.
 

Launching debug session  

The built project can be loaded by Debug session in the Simplicity Studio by clicking project in the Project Explorer and selecting “Debug As” a  predefined “Silicon Labs ARM program” debug configuration as shown:

 
 

The program will be halted by debug session at main() and the debugging procedures can be started. The program execution can be resumed by pressing “Resume” button. The following screen indicates that program was launched and halted at main()

 

Summary: 

The basic steps which are described above can help with getting stated with debugging the bootloader template provided by Silicon Labs. In addition, it can support maintaining the exiting functions and developing a new procedures where firmware troubleshooting is required.