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

3.3.3 Unlock Bootloader

Structure

HeaderLengthCMDDataCRC32
0x800x210x000x21D1...D32C1C2C3C4

Description

The command is used to unlock the bootloader. Only after bootloader unlock, all the protected commands listed in Section 3.3 are processed by the BSL.

If the host sends an incorrect password, the BSL sends the error response, then device enters sleep mode for 2 seconds. During this 2-second window, no command is received or processed. After 2 seconds, the host can send the next password. If an incorrect password is sent 3 times, a security alert action is taken. The security alert action is configurable in the BSL configuration. See Section 3.5.1.1 for more details.

Protected

No

Data

32 byte BSL password stored in the BSL configuration memory. Fresh device would have the default value all 0xFF.

Command Returns

BSL Acknowledgment and BSL core response with Message about the Status of operation. See section BSL Core Message for more details.

Example

Host: 80 21 00 21 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF 02 AA F0 3D

BSL: 00 08 02 00 3B 00 38 02 94 82