1.5.2 Serial Memory Bootloader execution flow

• On device reset after systme initialize, The Bootloader task starts executing from the SYS_Tasks()

• Once the Serial Memory driver is ready, it retrieves the Meta Data from serial memory

  • If any error in reading the Meta-Data it directly jumps Run application

• It checks if the Meta Data read is valid using the Prologue and Epilogue.

  • If valid

    • It stores the application start address and application size from meta data which will be used during programming operation

    • Checks if the Update Required flag is set. If set it jumps to Programming step Or continues to Trigger Check

  • If Invalid

    • It continues to Trigger Check

Trigger Check

• If there are no conditions to enter the firmware upgrade mode, the Bootloader jumps to Run application

  • Refer to Bootloader Trigger Methods for different conditions to enter firmware upgrade mode

Programming

• Starts reading the application binary from serial memory and perform erase/program operations on internal flash

• Once programming is completed, it generates CRC32 on programmed space of internal flash and verifies it against the CRC32 value stored in Meta data

• Once verification is complete it clears the update required flag in meta data and triggers reset to Run application

Run Application

• The application start address used to jump to application space can be

  • Application start address generated during compile time Or

  • Application start address retrieved from valid Meta Data

• Calls SYS_DeInitialize() function to release resources used

• Jumps to application space to run the updated application