SLUUDI6 December   2025 MSPM33C321A

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Overview of BSL Features
    2. 1.2 Terminology
    3. 1.3 Additional resources
  5. 2BSL Architecture
    1. 2.1 Design
      1. 2.1.1 Timeout Feature
        1. 2.1.1.1 Interface Autodetection
        2. 2.1.1.2 Command Reception
    2. 2.2 BSL Invocation
      1. 2.2.1 Application Request
      2. 2.2.2 GPIO Based Invocation
      3. 2.2.3 Debug Mailbox Command
      4. 2.2.4 Other BSL Invocation Methods
        1. 2.2.4.1 Pre-Boot Application Verification
        2. 2.2.4.2 Blank Device Handling
    3. 2.3 Memory
      1. 2.3.1 SRAM Memory Usage
    4. 2.4 BSL Non-Main Configuration
      1. 2.4.1  BSL Configuration ID
      2. 2.4.2  BSL Interface Pins (BLINTERFACE_PINS)
      3. 2.4.3  BSL Invoke Pin Configuration (BSLPIN_INVOKE)
      4. 2.4.4  Memory Readout Configuration
      5. 2.4.5  BSL Password
      6. 2.4.6  Application Revision Pointer
      7. 2.4.7  Security Alert Level
      8. 2.4.8  UART Baud Rate
      9. 2.4.9  I2C Slave Address
      10. 2.4.10 Configuration CRC
    5. 2.5 Changing BSL Configuration
      1. 2.5.1 Reference
      2. 2.5.2 Using SysConfig and Code Composer Studio (CCS)
      3. 2.5.3 Using Debug Interface
  6. 3Bootloader Protocol
    1. 3.1 Packet Format
    2. 3.2 BSL Protocol
      1. 3.2.1 BSL Acknowledgment
      2. 3.2.2 Peripheral Configuration
        1. 3.2.2.1 UART
        2. 3.2.2.2 I2C
        3. 3.2.2.3 CRC
    3. 3.3 Bootloader Core Commands
      1. 3.3.1  Connection
      2. 3.3.2  Get Device Info
      3. 3.3.3  Unlock Bootloader
      4. 3.3.4  Program Data
      5. 3.3.5  Program Data Fast
      6. 3.3.6  Readback Data
      7. 3.3.7  Flash Range Erase
      8. 3.3.8  Mass Erase
      9. 3.3.9  Factory Reset
      10. 3.3.10 Standalone Verification
      11. 3.3.11 Start Application
      12. 3.3.12 Change Baud Rate
    4. 3.4 Bootloader Core Response
      1. 3.4.1 BSL Core Message
      2. 3.4.2 Detailed Error
      3. 3.4.3 Memory Readback
      4. 3.4.4 Device Info
      5. 3.4.5 Standalone Verification
    5. 3.5 Bootloader Security
      1. 3.5.1 Password Protected Commands
        1. 3.5.1.1 Security Alert
      2. 3.5.2 BSL Entry
  7. 4Sample Program Flow with Bootloader
  8. 5Revision History

3.1 Packet Format

The BSL data packet has a layered structure. The BSL core command contains the actual command data to be processed by the BSL. In addition to the standard BSL commands, there can be wrapper data before and after each core command known as the peripheral interface code (PI Code). This wrapper data is information that is specific to the peripheral and protocol being used, and it contains information that allows for correct transmission of the BSL core command. Taken together, the wrapper and core command constitute a BSL data packet

PI CodeBSL Core DataPI Code