SPMA083 January   2022 TM4C129CNCPDT , TM4C129CNCPDT , TM4C129CNCZAD , TM4C129CNCZAD , TM4C129DNCPDT , TM4C129DNCPDT , TM4C129DNCZAD , TM4C129DNCZAD , TM4C129EKCPDT , TM4C129EKCPDT , TM4C129ENCPDT , TM4C129ENCPDT , TM4C129ENCZAD , TM4C129ENCZAD , TM4C129LNCZAD , TM4C129LNCZAD , TM4C129XKCZAD , TM4C129XKCZAD , TM4C129XNCZAD , TM4C129XNCZAD

 

  1.   Trademarks
  2. 1Implementation
    1. 1.1 Flash Boot Loader Project
      1. 1.1.1 Changes to the Example Project boot_serial
        1. 1.1.1.1 Changes to bl_config.h
        2. 1.1.1.2 New Functions Added
          1. 1.1.1.2.1 MyCheckUpdateFunc
          2. 1.1.1.2.2 MyReinitFunc
          3. 1.1.1.2.3 MyEndFunc
          4. 1.1.1.2.4 MyDecryptionFunc
    2. 1.2 Image Creation Project
    3. 1.3 Key Image Project
    4. 1.4 EK-TM4C129EXL Example Application Project
    5. 1.5 DK-TM4C129X Example Application Project
    6. 1.6 RAM-Based EEPROM Erase Project
  3. 2Example Walk Through
    1. 2.1 Build Environment
    2. 2.2 Importing the Examples into Code Composer Studio
    3. 2.3 Setting Keys and Variables
      1. 2.3.1 Keys
      2. 2.3.2 Initialization Vector
      3. 2.3.3 Application Start Address and Flash Size
        1. 2.3.3.1 APP_BASE
        2. 2.3.3.2 APP_END
        3. 2.3.3.3 RAM_BASE
    4. 2.4 Running the shared_key_image_encrypt Tool
    5. 2.5 Running the Shared Key Serial Boot Loader
      1. 2.5.1 Programming the Boot Loader
        1. 2.5.1.1 Erasing Existing Code and Keys
          1. 2.5.1.1.1 Erasing Flash and EEPROM With Code Composer Studio
          2. 2.5.1.1.2 Erasing Flash and EEPROM by Using the Unlock Procedure
        2. 2.5.1.2 Using the ROM Boot Loader to Program the Shared Key Boot Loader
      2. 2.5.2 Using the Shared Key Boot Loader to Program the Application Code
    6. 2.6 Returning to the Boot Loader
  4. 3Summary
1.1.1.2.2 MyReinitFunc

Since the keys can only be read from the EEPROM after a reset but before the application is invoked, the boot loader will not work when directly called from the application. Therefore, this function sets a predefined value in a static RAM location and then causes a software reset. The MyCheckUpdateFunc function checks for a software reset with the predefined RAM value and uses that condition to stay in the boot loader.