SWRA760A April   2023  – April 2024 AWR2544 , AWR2944

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Definitions, Abbreviations, Acronyms
  5. 2Introduction
  6. 3Basic Bootloader Flow
    1. 3.1 Boot Flow Introduction
    2. 3.2 Preparing the Application for Boot
      1. 3.2.1 SBL Image Format
      2. 3.2.2 Signing Scripts
    3. 3.3 ROM Boot
      1. 3.3.1 Boot mode - SFLASH
        1. 3.3.1.1 Image Load Sequence
        2. 3.3.1.2 Boot Mode UART
          1. 3.3.1.2.1 Image Download Sequence
    4. 3.4 SBL Boot
      1. 3.4.1 R5 SBL Flash Offset
      2. 3.4.2 R5 SBL Image Size
  7. 4Conclusion
  8. 5Revision History

3.1 Boot Flow Introduction

Booting user defined applications on a SOC involves multiples steps as listed below,

  • Firstly, there are multiple steps involved to convert a user application, created using a compiler+linker toolchain, into a binary format that is designed to be booted by the SOC
  • Next, we need to flash this binary file to the on-board serial flash.
  • Finally, when the SOC is powered on, the previously flashed binary is executed.
  • After powering on the device in functional mode, the boot flow takes place mainly in two steps
    • ROM boot: In which the RBL boots an SBL reading from the sFlash.
    • SBL boot: In which the secondary bootloader boots the application reading from the sFlash.
  • Note, that a system application (i.e. metaimage) itself can consist of multiple CPU specific application binaries that all collaborate together to realize the overall system goal.