SPRUID8D September   2020  – January 2022 TMS320F280040-Q1 , TMS320F280040C-Q1 , TMS320F280041 , TMS320F280041-Q1 , TMS320F280041C , TMS320F280041C-Q1 , TMS320F280045 , TMS320F280048-Q1 , TMS320F280048C-Q1 , TMS320F280049 , TMS320F280049-Q1 , TMS320F280049C , TMS320F280049C-Q1

 

  1.   Trademarks
  2. 1Introduction
  3. 2TMS320F28004x Product Safety Capability and Constraints
  4. 3TI Development Process for Management of Systematic Faults
    1. 3.1 TI New-Product Development Process
    2. 3.2 TI Functional Safety Development Process
  5. 4TMS320F28004x Product Overview
    1. 4.1 C2000 Architecture and Product Overview
      1. 4.1.1 TMS320F28004x MCU
    2. 4.2 Functional Safety Concept
      1. 4.2.1 VDA E-GAS Monitoring Concept With TMS320F28004x MCU
      2. 4.2.2 Fault Tolerant Time Interval (FTTI)
      3. 4.2.3 TMS320F28004x MCU Safe State
      4. 4.2.4 Operating States
      5. 4.2.5 Management of Faults
      6. 4.2.6 Suggestions for Improving Freedom From Interference
      7. 4.2.7 Suggestions for Addressing Common Cause Failures
    3. 4.3 C2000 Safety Diagnostics Libraries
      1. 4.3.1 Assumptions of Use - F28004x Self-Test Libraries
      2. 4.3.2 Operational Details - F28004x Self-Test Libraries
        1. 4.3.2.1 Operational Details – C28x Self-Test Library
        2. 4.3.2.2 Operational Details – CLA Self-Test Library
        3. 4.3.2.3 Operational Details – SDL
      3. 4.3.3 C2000 Safety STL Software Development Flow
      4. 4.3.4 Software Delivery Form (SDF) for STLs
    4. 4.4 TMS320F28004x MCU Safety Implementation
      1. 4.4.1 Assumed Safety Requirements
      2. 4.4.2 Example Safety Concept Implementation Options on TMS320F28004x MCU
        1. 4.4.2.1 Safety Concept Implementation: Option 1
        2. 4.4.2.2 Safety Concept Implementation: Option 2
  6. 5Brief Description of Safety Elements
    1. 5.1 TMS320F28004x MCU Infrastructure Components
      1. 5.1.1 Power Supply
      2. 5.1.2 Clock
      3. 5.1.3 Reset
      4. 5.1.4 System Control Module and Configuration Registers
      5. 5.1.5 Efuse Static Configuration
      6. 5.1.6 JTAG Debug, Trace, Calibration, and Test Access
    2. 5.2 Processing Elements
      1. 5.2.1 C28x Central Processing Unit (CPU)
      2. 5.2.2 Control Law Accelerator
    3. 5.3 Memory (Flash, SRAM and ROM)
      1. 5.3.1 Embedded Flash Memory
      2. 5.3.2 Embedded SRAM
      3. 5.3.3 Embedded ROM
    4. 5.4 On-Chip Communication Including Bus-Arbitration
      1. 5.4.1 Device Interconnect
      2. 5.4.2 Direct Memory Access (DMA)
      3. 5.4.3 Enhanced Peripheral Interrupt Expander (ePIE) Module
      4. 5.4.4 Dual Zone Code Security Module (DCSM)
      5. 5.4.5 CrossBar (X-BAR)
      6. 5.4.6 Timer
    5. 5.5 Digital I/O
      1. 5.5.1 General-Purpose Input/Output (GPIO) and Pinmuxing
      2. 5.5.2 Enhanced Pulse Width Modulators (ePWM)
      3. 5.5.3 High Resolution PWM (HRPWM)
      4. 5.5.4 Enhanced Capture (eCAP)
      5. 5.5.5 High Resolution Capture (HRCAP)
      6. 5.5.6 Enhanced Quadrature Encoder Pulse (eQEP)
      7. 5.5.7 Sigma Delta Filter Module (SDFM)
      8. 5.5.8 External Interrupt (XINT)
    6. 5.6 Analogue I/O
      1. 5.6.1 Analog-to-Digital Converter (ADC)
      2. 5.6.2 Buffered Digital to Analog Converter (DAC)
      3. 5.6.3 Comparator Subsystem (CMPSS)
      4. 5.6.4 Programmable Gain Amplifier (PGA)
    7. 5.7 Data Transmission
      1. 5.7.1 Controller Area Network (DCAN)
      2. 5.7.2 Serial Peripheral Interface (SPI)
      3. 5.7.3 Serial Communication Interface (SCI)
      4. 5.7.4 Inter-Integrated Circuit (I2C)
      5. 5.7.5 Fast Serial Interface (FSI)
      6. 5.7.6 Local Interconnect Network (LIN)
      7. 5.7.7 Power Management Bus Module (PMBus)
  7. 6Brief Description of Diagnostics
    1. 6.1 TMS320F28004x MCU Infrastructure Components
      1. 6.1.1  Clock Integrity Check Using CPU Timer
      2. 6.1.2  Clock Integrity Check Using HRPWM
      3. 6.1.3  EALLOW and MEALLOW Protection for Critical Registers
      4. 6.1.4  Efuse Autoload Self-Test
      5. 6.1.5  Efuse ECC
      6. 6.1.6  Efuse ECC Logic Self-Test
      7. 6.1.7  External Monitoring of Clock via XCLKOUT
      8. 6.1.8  External Monitoring of Warm Reset (XRSn)
      9. 6.1.9  External Voltage Supervisor
      10. 6.1.10 External Watchdog
      11. 6.1.11 Glitch Filtering on Reset Pins
      12. 6.1.12 Hardware Disable of JTAG Port
      13. 6.1.13 Internal Watchdog (WD)
      14. 6.1.14 Lock Mechanism for Control Registers
      15. 6.1.15 Missing Clock Detect (MCD)
      16. 6.1.16 NMIWD Reset Functionality
      17. 6.1.17 NMIWD Shadow Registers
      18. 6.1.18 Multi-Bit Enable Keys for Control Registers
      19. 6.1.19 Online Monitoring of Temperature
      20. 6.1.20 Periodic Software Read Back of Static Configuration Registers
      21. 6.1.21 Peripheral Clock Gating (PCLKCR)
      22. 6.1.22 Peripheral Soft Reset (SOFTPRES)
      23. 6.1.23 PLL Lock Profiling Using On-Chip Timer
      24. 6.1.24 Reset Cause Information
      25. 6.1.25 Software Read Back of Written Configuration
      26. 6.1.26 Software Test of ERRORSTS Functionality
      27. 6.1.27 Software Test of Missing Clock Detect Functionality
      28. 6.1.28 Software Test of Reset
      29. 6.1.29 Software Test of Watchdog (WD) Operation
      30. 6.1.30 Brownout Reset (BOR)
      31. 6.1.31 Dual clock comparator (DCC) - Type0
      32. 6.1.32 Peripheral Access Protection - Type 0
    2. 6.2 Processing Elements
      1. 6.2.1  CLA Handling of Illegal Operation, Illegal Results
      2. 6.2.2  CLA Liveness Check Using CPU
      3. 6.2.3  CPU Handling of Illegal Operation, Illegal Results and Instruction Trapping
      4. 6.2.4  Reciprocal Comparison by Software
      5. 6.2.5  Software Test of CLA
      6. 6.2.6  Software Test of CPU
      7. 6.2.7  Stack Overflow Detection
      8. 6.2.8  VCU CRC Check of Static Memory Contents
      9. 6.2.9  VCU CRC Auto Coverage
      10. 6.2.10 Disabling of Unused CLA Trigger Sources
      11. 6.2.11 Embedded Real Time Analysis and Diagnostic (ERAD) - Type 0
    3. 6.3 Memory (Flash, SRAM and ROM)
      1. 6.3.1  Bit Multiplexing in Flash Memory Array
      2. 6.3.2  Bit Multiplexing in SRAM Memory Array
      3. 6.3.3  Data Scrubbing to Detect/Correct Memory Errors
      4. 6.3.4  Flash ECC
      5. 6.3.5  Flash Program Verify and Erase Verify Check
      6. 6.3.6  Software Test of ECC Logic
      7. 6.3.7  Software Test of Flash Prefetch, Data Cache and Wait-States
      8. 6.3.8  Access Protection Mechanism for Memories
      9. 6.3.9  SRAM ECC
      10. 6.3.10 SRAM Parity
      11. 6.3.11 Software Test of Parity Logic
      12. 6.3.12 Software Test of SRAM
      13. 6.3.13 Background CRC for CLA-PROM (CLAPROMCRC)
      14. 6.3.14 Memory Power-On Self-Test (MPOST)
    4. 6.4 On-Chip Communication Including Bus-Arbitration
      1. 6.4.1  1oo2 Software Voting Using Secondary Free Running Counter
      2. 6.4.2  DMA Overflow Interrupt
      3. 6.4.3  Maintaining Interrupt Handler for Unused Interrupts
      4. 6.4.4  Power-Up Pre-Operational Security Checks
      5. 6.4.5  Majority Voting and Error Detection of Link Pointer
      6. 6.4.6  PIE Double SRAM Hardware Comparison
      7. 6.4.7  PIE Double SRAM Comparison Check
      8. 6.4.8  Software Check of X-BAR Flag
      9. 6.4.9  Software Test of ePIE Operation Including Error Tests
      10. 6.4.10 Disabling of Unused DMA Trigger Sources
    5. 6.5 Digital I/O
      1. 6.5.1  eCAP Application Level Safety Mechanism
      2. 6.5.2  ePWM Application Level Safety Mechanism
      3. 6.5.3  ePWM Fault Detection Using X-BAR
      4. 6.5.4  ePWM Synchronization Check
      5. 6.5.5  eQEP Application Level Safety Mechanism
      6. 6.5.6  eQEP Quadrature Watchdog
      7. 6.5.7  eQEP Software Test of Quadrature Watchdog Functionality
      8. 6.5.8  Hardware Redundancy
      9. 6.5.9  HRPWM Built-In Self-Check and Diagnostic Capabilities
      10. 6.5.10 Information Redundancy Techniques
      11. 6.5.11 Monitoring of ePWM by eCAP
      12. 6.5.12 Monitoring of ePWM by ADC
      13. 6.5.13 Online Monitoring of Periodic Interrupts and Events
      14. 6.5.14 SDFM Comparator Filter for Online Monitoring - Type 0
      15. 6.5.15 SD Modulator Clock Fail Detection Mechanism
      16. 6.5.16 Software Test of Function Including Error Tests
      17. 6.5.17 Monitoring of HRPWM by HRCAP
      18. 6.5.18 HRCAP Calibration Logic Test Feature
      19. 6.5.19 QMA Error Detection Logic
    6. 6.6 Analogue I/O
      1. 6.6.1  ADC Information Redundancy Techniques
      2. 6.6.2  ADC Input Signal Integrity Check
      3. 6.6.3  ADC Signal Quality Check by Varying Acquisition Window
      4. 6.6.4  CMPSS Ramp Generator Functionality Check
      5. 6.6.5  DAC to ADC Loopback Check
      6. 6.6.6  DAC to Comparator Loopback Check
      7. 6.6.7  PGA to ADC Loopback Test
      8. 6.6.8  Opens/Shorts Detection Circuit for ADC
      9. 6.6.9  VDAC Conversion by ADC
      10. 6.6.10 Disabling Unused Sources of SOC Inputs to ADC
    7. 6.7 Data Transmission
      1. 6.7.1  Information Redundancy Techniques Including End-to-End Safing
      2. 6.7.2  Bit Error Detection
      3. 6.7.3  CRC in Message
      4. 6.7.4  DCAN Acknowledge Error Detection
      5. 6.7.5  DCAN Form Error Detection
      6. 6.7.6  DCAN Stuff Error Detection
      7. 6.7.7  I2C Access Latency Profiling Using On-Chip Timer
      8. 6.7.8  I2C Data Acknowledge Check
      9. 6.7.9  Parity in Message
      10. 6.7.10 SCI Break Error Detection
      11. 6.7.11 Frame Error Detection
      12. 6.7.12 Overrun Error Detection
      13. 6.7.13 Software Test of Function Using I/O Loopback
      14. 6.7.14 SPI Data Overrun Detection
      15. 6.7.15 Transmission Redundancy
      16. 6.7.16 FSI Data Overrun/Underrun Detection
      17. 6.7.17 FSI Frame Overrun Detection
      18. 6.7.18 FSI CRC Framing Checks
      19. 6.7.19 FSI ECC Framing Checks
      20. 6.7.20 FSI Frame Watchdog
      21. 6.7.21 FSI RX Ping Watchdog
      22. 6.7.22 FSI Tag Monitor
      23. 6.7.23 FSI Frame Type Error Detection
      24. 6.7.24 FSI End of Frame Error Detection
      25. 6.7.25 FSI Register Protection Mechanisms
      26. 6.7.26 LIN Physical Bus Error Detection
      27. 6.7.27 LIN No-Response Error Detection
      28. 6.7.28 LIN Checksum Error Detection
      29. 6.7.29 Data Parity Error Detection
      30. 6.7.30 LIN ID Parity Error Detection
      31. 6.7.31 PMBus Protocol CRC in Message
      32. 6.7.32 Clock Timeout
      33. 6.7.33 Communication Access Latency Profiling Using On-Chip Timer
  8. 7References
  9.   A Safety Architecture Configurations
  10.   B Distributed Developments
    1.     B.1 How the Functional Safety Lifecycle Applies to Functional Safety-Compliant Products
    2.     B.2 Activities Performed by Texas Instruments
    3.     B.3 Information Provided
  11.   C Terms and Definitions
  12.   D Summary of Safety Features and Diagnostics
  13.   E Glossary
  14.   Revision History

6.5.16 Software Test of Function Including Error Tests

A software test can be utilized to test basic functionality of the module and to inject diagnostic errors and check for proper error response. Such a test can be executed at boot or periodically. Software requirements necessary are defined by the software implemented by the system integrator.

Ideas for creating some module specific tests functionality and error tests are given below:

  • SDFM functionality can be checked by sending a known input test sequence to the TMS320F28004x MCU, process it using the digital decimation filters and cross check the value against a known value. For detecting faults in comparator interrupt generation logic, a test pattern can be created to configure the high and low threshold register values to minimum and maximum values respectively. Interrupt should always be generated with such a configuration.
  • DMA functionality can be checked by transferring a known good data from a source memory to the destination memory and checking for data integrity after the transfer. The transfer can be initiated using the software trigger available (CONTROL.PERINTFRC). On chip timer can be used to profile the time required for such a data transfer.
  • Software test of input and output X-BAR module can be performed by having a loop created (output X-BAR can be used as stimulus to input X-BAR) using the input and output X-BAR, sending a known test sequence at the input and observing it at the final output. Integrity of ePWM X-BAR can be checked by sending the test stimulus and observing the response using ePWM trip or sync functionality.
  • Software test of XINT functionality can be checked by configuring the input X-BAR and forcing the corresponding GPIO register to generate an interrupt. The diagnostic coverage can be enhanced by performing checks for the polarity (XINTxCR.POLARITY) and enable (XINTxCR.ENABLE) functionality as well.
  • eCAP, HRCAP and eQEP functionality can be checked by looping back the PWM, HRPWM or GPIO outputs to the respective module inputs, providing a known good sequence as required by the module and observing the module output. In the case of eCAP and HRCAP, the test can be done internally with the help of input X-BAR.
  • ROM prefetch functionality can be checked using similar techniques as given in Section 6.3.7.
  • The ePWM module consists of Time-Base (TB), Counter Compare (CC), Action Qualifier (AQ), Dead-Band Generator (DB), PWM Chopper (PC), Trip Zone (TZ), Event Trigger (ET) and Digital Compare (DC) sub-modules. The individual sub-modules can be tested by providing suitable stimulus using ePWM and observing the response using one of the capture (time stamping) modules (eCAP, XINT, eQEP, and so forth). It is recommended to cover the various register values associated with application configuration while performing the software test. Due to the regular linear nature of the various sub-modules, it is possible to get high coverage using a software test.
  • A software test of SRAM wrapper logic should provide diagnostic coverage for arbitration between various masters having access to the particular SRAM and correct functioning of access protection. This is in addition to the test used to provide coverage of SRAM bit cells (see Section 6.3.12).
  • The interconnect (INC) functionality can be tested by writing complementary data-patterns like 0xA5A5,0x5A5A, and so forth from processing units from CPU and CLA, and reading back it from registers of the IPs’ connected via different bridges .The read-back data can be compared with expected golden values to ensure fault-free interconnect operation. This exercise can be repeated for different data width types of accesses (16 and 32 bits) and wide address ranges as applicable using both CPU and CLA. The CPU accesses can be repeated for different instances of peripherals used in application connected to various bridges as shown in Figure 4-1.

  • To test core functionality of the ADC module and post processing block (PPB), a set of predetermined voltage levels can be provided on the ADC input pin by external circuit or internal DAC. The ADC / PPB results thus obtained can be cross checked against the expected value to ensure proper operation. Extreme corner values of ADC being used in application can be applied and tested to check the successful conversion across the operational range. ADC configuration registers can be checked by writing complementary data-patterns, read back and compared to expected values.

  • DAC has a set of control registers that can be checked by writing complementary data-patterns like 0xA5A5, 0x5A5A, and so forth in 16-bit access mode. All the registers can be read back and compared to expected values. Registers can be checked for reset feature by configuring the registers to 0xA5A5 pattern, asserting soft reset of DAC, reading back the registers and comparing the read back value with the expected reset value. Lock register can be checked to ensure it is set-once. Also, the registers which are getting locked must not update when written. To test core functionality of the DAC module, it can be configured using software to provide a set of predetermined voltage levels. These voltage levels can be measured by external or internal ADC and results thus obtained can be cross checked against the expected value to ensure proper operation. Extreme corner values of DAC as per application can be programmed and tested to check the successful conversion of digital to analog module across a valid range.
  • Comparator sub-system (CMPSS) has a set of registers which can be checked by writing complementary data-patterns like 0xA5A5, 0x5A5A, and so forth in both 16 and 32 bit access modes. These can be read back and compared against expected values. These accesses can be covered by applicable masters viz. DMA, CLA and CPU. Features of the CMPSS module such as ramp decrement can be checked for counting down of RAMPDLYA after it is loaded from RAMPDLYS by a rising PWMSYNC signal. It should be ensured that the decrementer reduces to zero and stays there until next reload from RAMPDLYS. Extreme values of RAMPDLYS can be configured before count down. Digital filter CTRIPHFILCTL/CTRIPLFILCTL registers can be checked by configuring them to a variety of SAMPWIN (Sample window) and THRESH (Majority voting threshold) values, and then verifying COMPHSTS/COMPLSTS changes with change in filter output. Applicable range of filter clock pre-scaler values (CTRIPLFILCLKCTL) can be exercised to ensure that filter samples correctly.
  • The general operation of the CPU Timers can be tested by a software test by loading 32-bit counter register TIMH from period register PRDH, starts decrementing of the counter on every clock cycle. When counter reaches zero a timer interrupt output generates an interrupt pulse. While testing the timer functionality vary the Timer Prescale Counter (TPR) value and also vary input clocks by selecting clock source as SYSCLK, INTOSC1, INTOSC2, or XTAL. Test interrupts generation capability at the end of the timer counting. Check for the time overflow flag and Timer reload (TRB) functions in TCR register for correct functioning.
  • A software test function in DCSM can be implemented independently in zone1, zone2 and unsecured zone to check DCSM functionality. Device security configurations are loaded from OTP to DCSM during the device boot phase. The test function can implement access filtering checks (read-write and execute permissions) to RAMs and flash sectors belonging to the same zone and different zone. An additional check for EXEONLY configuration can also be implemented for the RAMs and flash sectors to ensure that all access other than execute access is blocked.