SPRAD28 October   2022 AM2431 , AM2432 , AM2434 , AM2631 , AM2631-Q1 , AM2632 , AM2632-Q1 , AM2634 , AM2634-Q1 , AM26C31 , AM26C31-EP , AM26C31C , AM26C31I , AM26C31M , AM26C32 , AM26C32-EP , AM26C32C , AM26C32M , AM26LS31 , AM26LS31M , AM26LS32A , AM26LS32AC , AM26LS32AM , AM26LS33A , AM26LS33A-SP , AM26LS33AM , AM26LV31 , AM26LV31E , AM26LV31E-EP , AM26LV32 , AM26LV32E , AM26LV32E-EP , AM26S10 , AM2732 , AM2732-Q1

 

  1.   Abstract
  2.   Trademarks
  3. 1 Building for Debug
    1. 1.1 Disable Code Optimization
    2. 1.2 Using the Debug SDK Libraries
  4. 2 Code Composer Studio Stop-Mode Debugging
    1. 2.1 Configuring the Debugger
    2. 2.2 Breakpoints and Watchpoints
      1. 2.2.1 Software Breakpoints
      2. 2.2.2 Hardware Breakpoints
      3. 2.2.3 Watchpoints
    3. 2.3 Inspecting Device Registers
    4. 2.4 Inspecting Disassembly
  5. 3 Debug Logging
    1. 3.1 Logging Methods
    2. 3.2 Log Zones
    3. 3.3 Asserts
    4. 3.4 Example Usage
  6. 4 Multi-Core Debug
    1. 4.1 Grouping Cores
      1. 4.1.1 Fixed Group
      2. 4.1.2 Hiding Cores
    2. 4.2 Using Multiple Workbench Windows
    3. 4.3 Global Breakpoints
  7. 5 Debugging Arm Cortex-R5 Exceptions
    1. 5.1 Exception Priority Order
    2. 5.2 Aborts
      1. 5.2.1 Data Aborts
        1. 5.2.1.1 Alignment
        2. 5.2.1.2 Background Aborts
        3. 5.2.1.3 Permission
        4. 5.2.1.4 Synchronous/Asynchronous External
        5. 5.2.1.5 Synchronous/Asynchronous ECC
      2. 5.2.2 Synchronous/Asynchronous Aborts
        1. 5.2.2.1 Changing an Asynchronous Abort to a Synchronous Abort
        2. 5.2.2.2 Synchronous Abort
        3. 5.2.2.3 Asynchronous Abort
        4. 5.2.2.4 Debugging Asynchronous Abort
      3. 5.2.3 Prefetch Abort
        1. 5.2.3.1 Possible Reasons for Prefetch Abort
        2. 5.2.3.2 Handling Prefetch Abort Exception
      4. 5.2.4 Undefined Instruction
        1. 5.2.4.1 Possible Reasons for Undefined Instruction Exception
        2. 5.2.4.2 Handling Undefined Instruction Exception
    3. 5.3 Fetching Core Registers Inside an Abort Handler
  8. 6 Debugging Arm Cortex-M4 Exceptions
    1. 6.1 Exception Entry and Exit Sequence
      1. 6.1.1 Entry Sequence
      2. 6.1.2 Exception Exit Sequence
      3. 6.1.3 Decoding EXC_RETURN Value
    2. 6.2 Faults Handling
      1. 6.2.1 There are 15 System Exceptions by Arm Cortex M Processors
        1. 6.2.1.1 Causes of Faults
      2. 6.2.2 HardFault Exception
        1. 6.2.2.1 Causes of HardFault Exception
      3. 6.2.3 Configurable Fault Exceptions
        1. 6.2.3.1 Mem Manage Fault Exception
        2. 6.2.3.2 BusFault Exception
        3. 6.2.3.3 Usage Fault Exception
      4. 6.2.4 Control Registers
        1. 6.2.4.1 SHP - System Handler Priority Register
      5. 6.2.5 Status Registers
        1. 6.2.5.1 Undefined Instruction Handling Example
        2. 6.2.5.2 Invalid State Handling Example
      6. 6.2.6 Printing the Stack Frame
  9. 7 Debugging Memory
    1. 7.1 Viewing Device Memory
    2. 7.2 Linker Command File (linker.cmd)
      1. 7.2.1 The Memory Directive
      2. 7.2.2 The Sections Directive
    3. 7.3 Stack Overflow
      1. 7.3.1 -fstack-protector
      2. 7.3.2 -fstack-protector-strong
      3. 7.3.3 -fstack-protector-all
      4. 7.3.4 Enabling Stack Smashing Detection
      5. 7.3.5 Enabling Stack Smashing Detection
    4. 7.4 Variables and Expressions View in CCS
    5. 7.5 Understanding Your Application's Memory Allocation
    6. 7.6 FreeRTOS ROV
  10. 8 Debugging Boot
    1. 8.1 ROM Boot
    2. 8.2 SBL Boot
    3. 8.3 GEL Files
      1. 8.3.1 Debugging Init Code
        1. 8.3.1.1 Disable Auto-Run to Main
  11. 9 Debugging Real-Time Control Loops
    1. 9.1 Trace
      1. 9.1.1 Processor / Core Trace
      2. 9.1.2 How to Use CCS to Capture Trace Data on an AM243x
    2. 9.2 Code Profile / Coverage
      1. 9.2.1 CCS Count Event
    3. 9.3 Real-Time UART Monitor
      1. 9.3.1 Confirm CCS Features
      2. 9.3.2 Create Target Configuration File
      3. 9.3.3 Add Serial Command Monitor Software
      4. 9.3.4 Launch Real Time Debug
  12. 10E2E Support Forums

6.2.4 Control Registers

The System control block (SCB) provides system implementation information, and system control. This includes configuration, control, and reporting of the system exceptions. Some of its registers are used to control fault exceptions:

  • CCR - Configuration and Control Register, controls the behavior of the UsageFault for divideby-zero and unaligned memory accesses
  • SHP - System Handler Priority Registers, control the exception priority
  • SHCRS - System Handler Control and State Register, enables the system handlers, and indicates the pending status of the BusFault, MemManage fault, and SVC exceptions
Register Address Description
CCR 0xE000ED14 Configuration and Control Register: contains enable bits for trapping of divide-by-zero and unaligned accesses with the UsageFault.
SHP 0xE000ED18 System Handler Priority registers: control the priority of exception handlers.
SHCRS 0xE000ED24 The SHCSR enables the system handlers, and indicates:

  • The pending status of the BusFault, MemManage fault, and SVC exceptions

  • The active status of the system handlers
GUID-20220417-SS0I-TJ7K-8Q0C-FHP4F82H44JX-low.jpg Figure 6-2 CCR - Configuration and Control Register

The following bits of the CCR register control the behavior of the Usage Fault:

DIV_0_TRP: Enables UsageFault when the processor executes an SDIV or UDIV instruction with a divisor of 0:

  • When '0' = do not trap divide by 0; a divide by 0 returns a quotient of 0.
  • When '1' = trap divide by 0.

UNALIGN_TRP: Enable UsageFault when a memory access to unaligned addresses are performed:

  • When '0' = do not trap unaligned halfword and word accesses
  • When '1' = trap unaligned halfword and word accesses; an unaligned access generates a UsageFault