SPRADT6 July   2026 AWR2944 , AWR2944P

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction to AWR294x and Safety Modules
  5. 2In-Depth Guide to AWR294x Safety Diagnostic Library
    1. 2.1  DPL Data Porting Layer
    2. 2.2  CCM Core Compare Module
    3. 2.3  DCC Dual Clock Comparator
    4. 2.4  ECC Error Correction Code
    5. 2.5  ECC Bus Safety
    6. 2.6  HWA Hardware Accelerator Safety
    7. 2.7  MCRC Cyclic Redundancy Check
    8. 2.8  Parity
    9. 2.9  PBIST Programmable Built-In Self-Test
    10. 2.10 Reset Management
    11. 2.11 ROM Checksum
    12. 2.12 RTI Real-Time Windowed Watchdog
    13. 2.13 STC Self-Test Controller
  6. 3Summary
  7. 4Glossary
  8. 5References

2.12 RTI Real-Time Windowed Watchdog

The RTI DWWD (Digital Windowed Watchdog) requires watchdog servicing (kicking) to be completed within a specific time window; kicking too early or too late will trigger a safety response. It effectively detects CPU execution flow anomalies (runaway, deadlock, execution delay).

Window size ratio configuration:

Table 2-22 RTI Window Ratio Configuration
Window Size Open Window Ratio Closed Window Ratio
100% 100% 0% (Traditional watchdog behavior)
50% 50% 50%
25% 25% 75%
12.5% 12.5% 87.5%
6.25% 6.25% 93.75%
3.125% 3.125% 96.875%

The test workflow covers four use cases (UC1-UC4):

Table 2-23 RTI Module Test Workflow
Step Action Description
1 Configure RTI parameters Sets window size and preload values
2 Start watchdog Calls SDL_RTI_start
3 UC1: Correct Service Servicing within the open window, no error interrupt
4 UC2: Permanent Fault No servicing triggers timeout, ESM interrupt triggered
5 UC3: Early Service Servicing within the closed window, ESM interrupt triggered
6 UC4: Window Switching Configures different window ratios to verify validation timing
Table 2-24 RTI Module Function Descriptions
Key Function Functions
SDL_RTI_config Configures windowed watchdog parameters (window size/preload values)
SDL_RTI_verifyConfig Verifies the RTI configuration
SDL_RTI_start Starts windowed watchdog
SDL_RTI_service Services (kicks) the watchdog
SDL_RTI_writeWinSz Dynamically modifies the window size
SDL_RTI_getStatus Gets interrupt status
SDL_RTI_clearStatus Clears interrupt status