SPMU447 June   2026 CC2755P20

 

  1.   1
  2.   Read This First
    1.     About This Manual
    2.     Devices
    3.     Register, Field, and Bit Calls
    4.     Related Documentation
    5.     Trademarks
  3. 1 Architectural Overview
    1. 1.1  Target Applications
    2. 1.2  Introduction
    3. 1.3  Arm Cortex-M33
      1. 1.3.1 Processor Core
      2. 1.3.2 SysTick Timer
      3. 1.3.3 Nested Vectored Interrupt Controller
      4. 1.3.4 System Control Block (SCB)
      5. 1.3.5 TI Machine Learning Instruction Extensions
    4. 1.4  On-Chip Memory
      1. 1.4.1 SRAM
      2. 1.4.2 FLASH
      3. 1.4.3 ROM
    5. 1.5  Power Supply System
      1. 1.5.1 VDDS
      2. 1.5.2 VDDIO
      3. 1.5.3 VDDR
      4. 1.5.4 VDDD Digital Core Supply
      5. 1.5.5 DC/DC Converter
    6. 1.6  Radio
    7. 1.7  Hardware Security Module
    8. 1.8  AES 128-Bit Cryptographic Accelerator
    9. 1.9  System Timer (SYSTIM)
    10. 1.10 General Purpose Timers (LGPT)
    11. 1.11 Always-ON (AON) or Ultra-Low Leakage (ULL) Domain
      1. 1.11.1 Watchdog Timer
      2. 1.11.2 Battery and Temperature Monitor
      3. 1.11.3 Voltage Glitch Monitor (VGM)
      4. 1.11.4 Real-Time Clock (RTC)
      5. 1.11.5 Low Power Comparator
    12. 1.12 Direct Memory Access
    13. 1.13 System Control and Clock
    14. 1.14 Communication Peripherals
      1. 1.14.1 UART
      2. 1.14.2 I2C
      3. 1.14.3 SPI
      4. 1.14.4 CAN-FD
      5. 1.14.5 I2S
    15. 1.15 Programmable I/Os
    16. 1.16 Algorithm Processing Unit (APU)
    17. 1.17 Serial Wire Debug (SWD)
  4. 2 Arm® Cortex®-M33 Processor
    1. 2.1 Arm® Cortex®-M33 Processor Introduction
    2. 2.2 M33 Instantiation Parameters
    3. 2.3 Arm® Cortex®-M33 System Peripheral Details
      1. 2.3.1 Floating Point Unit (FPU)
      2. 2.3.2 Memory Protection Unit (MPU)
      3. 2.3.3 Digital Signal Processing (DSP)
      4. 2.3.4 Security Attribution Unit (SAU)
      5. 2.3.5 System Timer (SysTick)
      6. 2.3.6 Nested Vectored Interrupt Controller (NVIC)
      7. 2.3.7 System Control Block (SCB)
      8. 2.3.8 System Control Space (SCS)
    4. 2.4 CPU Sub-System Peripheral Details
      1. 2.4.1 Trace Port Interface Unit (TPIU)
      2. 2.4.2 DAP Bridge and Debug Authentication
      3. 2.4.3 Implementation Defined Attribution Unit (IDAU)
      4. 2.4.4 Custom Datapath Extension (CDE)
    5. 2.5 Programming Model
      1. 2.5.1 Modes of Operation and Execution
        1. 2.5.1.1 Security States
        2. 2.5.1.2 Operating Modes
        3. 2.5.1.3 Operating States
        4. 2.5.1.4 Privileged Access and Unprivileged User Access
      2. 2.5.2 Instruction Set Summary
      3. 2.5.3 Memory Model
        1. 2.5.3.1 Private Peripheral Bus
        2. 2.5.3.2 Unaligned Accesses
      4. 2.5.4 Processor Core Registers Summary
      5. 2.5.5 Exceptions
        1. 2.5.5.1 Exception Handling and Prioritization
    6. 2.6 TrustZone
      1. 2.6.1 Overview
      2. 2.6.2 M33 Configuration
      3. 2.6.3 Description of Elements
        1. 2.6.3.1 IDAU (Implementation Defined Attribution Unit)
          1. 2.6.3.1.1 Expected Use
        2. 2.6.3.2 Gaskets
          1. 2.6.3.2.1 Periphery Gasket
          2. 2.6.3.2.2 Controller Gasket
        3. 2.6.3.3 Memories
        4. 2.6.3.4 TCM
      4. 2.6.4 TCM Registers
    7. 2.7 Arm® Cortex®-M33 Registers
      1. 2.7.1  CPU_ROM_TABLE Registers
      2. 2.7.2  TPIU Registers
      3. 2.7.3  DCB Registers
      4. 2.7.4  DIB Registers
      5. 2.7.5  DWT Registers
      6. 2.7.6  FPB Registers
      7. 2.7.7  FPE Registers
      8. 2.7.8  ICB Registers
      9. 2.7.9  ITM Registers
      10. 2.7.10 MPU Registers
      11. 2.7.11 NVIC Registers
      12. 2.7.12 SAU Registers
      13. 2.7.13 SCB Registers
      14. 2.7.14 SYSTICK Registers
      15. 2.7.15 Clock Control
      16. 2.7.16 Protocol Descriptions
      17. 2.7.17 Reset Considerations
        1. 2.7.17.1 Hardware Reset Considerations
      18. 2.7.18 Initialization
      19. 2.7.19 Interrupt and Event Support
        1. 2.7.19.1 Connection to Event Fabric
      20. 2.7.20 Power Management
  5. 3 Memory Map
    1. 3.1 Memory Map
  6. 4 Interrupts and Events
    1. 4.1 Exception Model
      1. 4.1.1 Exception States
      2. 4.1.2 Exception Types
      3. 4.1.3 Exception Handlers
      4. 4.1.4 Vector Table
      5. 4.1.5 Exception Priorities
      6. 4.1.6 Interrupt Priority Grouping
      7. 4.1.7 Exception Entry and Return
        1. 4.1.7.1 Exception Entry
        2. 4.1.7.2 Exception Return
    2. 4.2 Fault Handling
      1. 4.2.1 Fault Types
      2. 4.2.2 Fault Escalation to HardFault
      3. 4.2.3 Fault Status Registers and Fault Address Registers
      4. 4.2.4 Lockup
    3. 4.3 Security State Switches
    4. 4.4 Event Fabric
      1. 4.4.1 Introduction
      2. 4.4.2 Overview
      3. 4.4.3 Registers
      4. 4.4.4 AON Event Fabric
        1. 4.4.4.1 AON Common Input Events List
        2. 4.4.4.2 AON Event Subscribers
        3. 4.4.4.3 Power Management Controller (PMCTL)
        4. 4.4.4.4 Real Time Clock (RTC)
        5. 4.4.4.5 AON to MCU Event Fabric
      5. 4.4.5 MCU Event Fabric
        1. 4.4.5.1 Common Input Event List
        2. 4.4.5.2 MCU Event Subscribers
          1. 4.4.5.2.1 System CPU
          2. 4.4.5.2.2 Non-Maskable Interrupt (NMI)
    5. 4.5 Digital Test Bus (DTB)
    6. 4.6 EVTSVT Registers
    7. 4.7 EVTULL Registers
  7. 5 Debug Subsystem
    1. 5.1  Introduction
    2. 5.2  Block Diagram
    3. 5.3  Overview
      1. 5.3.1 Physical Interface
      2. 5.3.2 Debug Access Ports
    4. 5.4  Debug Features
      1. 5.4.1 Processor Debug
      2. 5.4.2 Breakpoint Unit (BPU)
      3. 5.4.3 Peripheral Debug
    5. 5.5  Behavior in Low Power Modes
    6. 5.6  Restricting Debug Access
    7. 5.7  Mailbox (DSSM)
    8. 5.8  Mailbox Events
      1. 5.8.1 CPU Interrupt Event (AON_DBG_COMB)
    9. 5.9  Software Considerations
    10. 5.10 DBGSS Registers
  8. 6 Power, Reset, and Clocking
    1. 6.1 Introduction
    2. 6.2 System CPU Modes
    3. 6.3 Supply System
      1. 6.3.1 Internal DC/DC Converter and Global LDO
    4. 6.4 Power States
      1. 6.4.1 RESET
      2. 6.4.2 SHUTDOWN
      3. 6.4.3 ACTIVE
      4. 6.4.4 IDLE
      5. 6.4.5 STANDBY
      6. 6.4.6 PMCTL Registers
    5. 6.5 Digital Power Partitioning
    6. 6.6 Clocks
      1. 6.6.1 Block Diagram
      2. 6.6.2 LF clock
        1. 6.6.2.1 LFINC Measurement Mechanism
        2. 6.6.2.2 LFINC Filtering
      3. 6.6.3 HFOSC
        1. 6.6.3.1 HFOSC Control and Qualification
        2. 6.6.3.2 HFOSC Tracking Loop
      4. 6.6.4 AFOSC
        1. 6.6.4.1 AFOSC Control and Qualification
        2. 6.6.4.2 AFOSC Tracking Loop
        3. 6.6.4.3 AFOSC Ratio
      5. 6.6.5 CLKSVT
      6. 6.6.6 CLKULL
      7. 6.6.7 CKMD Registers
      8. 6.6.8 CLKCTL Registers
    7. 6.7 Resets
      1. 6.7.1 Watchdog Timer (WDT)
      2. 6.7.2 RTC Reset
      3. 6.7.3 LF Loss Detection
    8. 6.8 AON (REG3V3) Register Bank
  9. 7 Internal Memory
    1. 7.1 SRAM
      1. 7.1.1 Overview
        1. 7.1.1.1 Purpose of the Peripheral
        2. 7.1.1.2 Features
        3. 7.1.1.3 Functional Block Diagram
      2. 7.1.2 Peripheral Functional Description
        1. 7.1.2.1 Parity Error Detection
          1. 7.1.2.1.1 Parity Error Debug Register
        2. 7.1.2.2 Extension Mode
        3. 7.1.2.3 Initialization
        4. 7.1.2.4 TrustZone Watermarking
      3. 7.1.3 SRAMCTRL Registers
    2. 7.2 VIMS
      1. 7.2.1 Overview
        1. 7.2.1.1 Purpose of the Peripheral
        2. 7.2.1.2 Features
        3. 7.2.1.3 Functional Block Diagram
      2. 7.2.2 Peripheral Functional Description
        1. 7.2.2.1 Dedicated 8KB CPU Cache
        2. 7.2.2.2 Dedicated 2KB HSM Cache
        3. 7.2.2.3 Dedicated 128-Bit Line Buffer
        4. 7.2.2.4 ROM
        5. 7.2.2.5 Flash
        6. 7.2.2.6 Auxiliary Regions
        7. 7.2.2.7 Flash Partition and Protection
          1. 7.2.2.7.1 Main Region
          2. 7.2.2.7.2 Read Protection
          3. 7.2.2.7.3 Sticky Write/Erase Protection
        8. 7.2.2.8 TrustZone Watermark
        9. 7.2.2.9 Debug Access
      3. 7.2.3 VIMS Registers
    3. 7.3 FLASH
      1. 7.3.1 FLASH Registers
  10. 8 Hardware Security Module (HSM)
    1. 8.1 Introduction
    2. 8.2 Overview
    3. 8.3 One-Time-Programmable (OTP) Controller
      1. 8.3.1 High-Level Sequence to Handle OTP Requests
    4. 8.4 Mailbox and Register Access Firewall
    5. 8.5 DMA Firewall
    6. 8.6 Coprocessor
    7. 8.7 HSM FW
      1. 8.7.1 Acquiring the Latest HSM FW
      2. 8.7.2 Programming HSM FW
      3. 8.7.3 Optional Customer Signing of HSM FW
    8. 8.8 HSM Registers
    9. 8.9 HSMCRYPTO Registers
  11. 9 Device Boot and Bootloader
    1. 9.1 Device Boot and Programming
      1. 9.1.1 Boot Flow
      2. 9.1.2 Boot Status
      3. 9.1.3 Boot Protection/Locking Mechanisms
      4. 9.1.4 Debug and Active SWD Connections at Boot
        1. 9.1.4.1 Secure Debug and Persistent Debug
      5. 9.1.5 Flashless Test Mode and Tools Client Mode
        1. 9.1.5.1 Flashless Test Mode
        2. 9.1.5.2 Tools Client Mode
      6. 9.1.6 Retest Mode and Return-to-Factory Procedure
      7. 9.1.7 Disabling SWD Debug Port
    2. 9.2 Flash Programming
      1. 9.2.1 CCFG
      2. 9.2.2 CCFG Permissions/Restrictions that Affect Flash Programming
      3. 9.2.3 SACI Flash Programming Commands
      4. 9.2.4 Flash Programming Flows
        1. 9.2.4.1 Initial Programming of a New Device
        2. 9.2.4.2 Reprogramming of Previously Programmed Device
        3. 9.2.4.3 Add User Record on Already Programmed Device as Part of Commissioning Step
        4. 9.2.4.4 Incrementally Program Ancillary Data to MAIN Flash Sectors of a Previously Programmed Device
        5. 9.2.4.5 Reprogramming of Only the Main Flash Application of a Previously Programmed Device
    3. 9.3 Device Management Command Interface
      1. 9.3.1 SACI Communication Protocol
        1. 9.3.1.1 Host Side Protocol
        2. 9.3.1.2 Command Format
        3. 9.3.1.3 Response Format
        4. 9.3.1.4 Response Result Field
        5. 9.3.1.5 Command Sequence Tag
        6. 9.3.1.6 Host Side Timeout
      2. 9.3.2 SACI Commands
        1. 9.3.2.1 Miscellaneous Commands
          1. 9.3.2.1.1 SACI_CMD_MISC_NO_OPERATION
          2. 9.3.2.1.2 SACI_CMD_MISC_GET_DIE_ID
          3. 9.3.2.1.3 SACI_CMD_MISC_GET_CCFG_USER_REC
          4. 9.3.2.1.4 SACI_CMD_GET_SECBOOT_HSMFW_UPDATE_STATUS
          5. 9.3.2.1.5 SACI_CMD_HSM_GET_SYS_INFO
        2. 9.3.2.2 Debug Commands
          1. 9.3.2.2.1 SACI_CMD_DEBUG_EXIT_SACI_HALT
          2. 9.3.2.2.2 SACI_CMD_DEBUG_EXIT_SACI_SHUTDOWN
          3. 9.3.2.2.3 SACI_CMD_DEBUG_REQ_KEY_ID
          4. 9.3.2.2.4 SACI_CMD_DEBUG_REQ_CHALLENGE
          5. 9.3.2.2.5 SACI_CMD_DEBUG_SUBMIT_CHALLENGE_RESP
          6. 9.3.2.2.6 SACI_CMD_DEBUG_CLOSE_SESSION
          7. 9.3.2.2.7 SACI_CMD_BLDR_APP_RESET_DEVICE
          8. 9.3.2.2.8 SACI_CMD_BLDR_APP_EXIT_SACI_RUN
        3. 9.3.2.3 Flash Programming Commands
          1. 9.3.2.3.1  SACI_CMD_FLASH_ERASE_CHIP
          2. 9.3.2.3.2  SACI_CMD_FLASH_ERASE_MAIN_APP
          3. 9.3.2.3.3  SACI_CMD_FLASH_PROG_CCFG_SECTOR
          4. 9.3.2.3.4  SACI_CMD_FLASH_PROG_CCFG_USER_REC
          5. 9.3.2.3.5  SACI_CMD_FLASH_PROG_SCFG_SECTOR
          6. 9.3.2.3.6  SACI_CMD_FLASH_PROG_MAIN_SECTOR
          7. 9.3.2.3.7  SACI_CMD_FLASH_PROG_MAIN_PIPELINED
          8. 9.3.2.3.8  SACI_CMD_FLASH_VERIFY_MAIN_SECTORS
          9. 9.3.2.3.9  SACI_CMD_FLASH_VERIFY_CCFG_SECTOR
          10. 9.3.2.3.10 SACI_CMD_FLASH_VERIFY_SCFG_SECTOR
    4. 9.4 Bootloader Support
      1. 9.4.1 Bootloader v.s Secure Boot
    5. 9.5 ROM Serial Bootloader
      1. 9.5.1 ROM Serial Bootloader Interfaces
        1. 9.5.1.1 Packet Handling
          1. 9.5.1.1.1 Packet Acknowledge and Not-Acknowledge Bytes
        2. 9.5.1.2 Transport Layer
          1. 9.5.1.2.1 UART Transport
            1. 9.5.1.2.1.1 UART Baud Rate Automatic Detection
          2. 9.5.1.2.2 SPI Transport
      2. 9.5.2 ROM Serial Bootloader Parameters
      3. 9.5.3 ROM Serial Bootloader Commands
        1. 9.5.3.1 BLDR_CMD_PING
        2. 9.5.3.2 BLDR_CMD_GET_STATUS
        3. 9.5.3.3 BLDR_CMD_GET_PART_ID
        4. 9.5.3.4 BLDR_CMD_RESET
        5. 9.5.3.5 BLDR_CMD_CHIP_ERASE
        6. 9.5.3.6 BLDR_CMD_CRC32
        7. 9.5.3.7 BLDR_CMD_DOWNLOAD
        8. 9.5.3.8 BLDR_CMD_DOWNLOAD_CRC
        9. 9.5.3.9 BLDR_CMD_SEND_DATA
      4. 9.5.4 Bootloader Firmware Update Example
  12. 10Device Configuration
    1. 10.1 Guidelines for Securely Configuring Your Device
      1. 10.1.1 Enabling and Configuring Secure Boot
      2. 10.1.2 Configure Debug Access
      3. 10.1.3 Configure Flash Protections
      4. 10.1.4 Configure Device Permissions
      5. 10.1.5 Configure HSM FW Update Keys
      6. 10.1.6 Configure emSensor
    2. 10.2 Factory Configuration (FCFG)
    3. 10.3 Customer Configuration (CCFG)
    4. 10.4 Security Configuration (SCFG)
  13. 11Secure Boot
    1. 11.1  Secure Boot
    2. 11.2  Execution Flow
    3. 11.3  ROM API
      1. 11.3.1 HAPI (Hardware API)
      2. 11.3.2 Registers
    4. 11.4  Configuration
      1. 11.4.1 Slot Configuration
      2. 11.4.2 Policy
        1. 11.4.2.1 Authentication Method
        2. 11.4.2.2 Authentication Algorithm
        3. 11.4.2.3 Update Mode
          1. 11.4.2.3.1 Overwrite
          2. 11.4.2.3.2 XIP Revert Enabled/Disabled
      3. 11.4.3 Key Update Key Hash
      4. 11.4.4 Key Ring
      5. 11.4.5 Boot Seed
    5. 11.5  Generic Image Format
    6. 11.6  Application Update
      1. 11.6.1 Image Format
    7. 11.7  Secondary Secure Bootloader Update
      1. 11.7.1 Image Format
      2. 11.7.2 Update Pattern
    8. 11.8  Key Update
      1. 11.8.1 Image Format
    9. 11.9  Antirollback
    10. 11.10 Version Log (VLOG)
      1. 11.10.1 Record structure
    11. 11.11 Fallback
    12. 11.12 ROM Panic
  14. 12General Purpose Timers (LGPT)
    1. 12.1 Overview
    2. 12.2 Block Diagram
    3. 12.3 Functional Description
      1. 12.3.1  Prescaler
      2. 12.3.2  Counter
      3. 12.3.3  Target
      4. 12.3.4  Channel Input Logic
      5. 12.3.5  Channel Output Logic
      6. 12.3.6  Channel Actions
        1. 12.3.6.1 Period and Pulse Width Measurement
        2. 12.3.6.2 Clear on Zero, Toggle on Compare Repeatedly
        3. 12.3.6.3 Set on Zero, Toggle on Compare Repeatedly
      7. 12.3.7  Channel Capture Configuration
      8. 12.3.8  Channel Filters
        1. 12.3.8.1 Setting up the Channel Filters
      9. 12.3.9  Synchronize Multiple LGPT Timers
      10. 12.3.10 Interrupts, ADC Trigger, and DMA Request
    4. 12.4 Timer Modes
      1. 12.4.1 Quadrature Decoder
      2. 12.4.2 DMA
      3. 12.4.3 IR Generation
      4. 12.4.4 Fault and Park
      5. 12.4.5 Deadband
      6. 12.4.6 Deadband, Fault, and Park
      7. 12.4.7 Example Application: Brushless DC (BLDC) Motor
    5. 12.5 LGPT0 Registers
    6. 12.6 LGPT1 Registers
    7. 12.7 LGPT2 Registers
    8. 12.8 LGPT3 Registers
  15. 13Algorithm Processing Unit (APU)
    1. 13.1 Introduction
    2. 13.2 APU Related Collateral
    3. 13.3 Functional Description
    4. 13.4 APU Operation
    5. 13.5 Interrupts and Events
    6. 13.6 Data Representation
    7. 13.7 Data Memory
    8. 13.8 Software
    9. 13.9 APU Registers
  16. 14Voltage Glitch Monitor (VGM)
    1. 14.1 Overview
    2. 14.2 Features and Operation
  17. 15System Timer (SYSTIM)
    1. 15.1 Overview
    2. 15.2 Block Diagram
    3. 15.3 Functional Description
      1. 15.3.1 Common Channel Features
        1. 15.3.1.1 Compare Mode
        2. 15.3.1.2 Capture Mode
        3. 15.3.1.3 Additional Channel Arming Methods
      2. 15.3.2 Interrupts and Events
    4. 15.4 SYSTIM Registers
  18. 16Real Time Clock (RTC)
    1. 16.1 Introduction
    2. 16.2 Block Diagram
    3. 16.3 Interrupts and Events
      1. 16.3.1 Input Event
      2. 16.3.2 Output Event
      3. 16.3.3 Arming and Disarming Channels
    4. 16.4 CAPTURE and COMPARE Configurations
      1. 16.4.1 CHANNEL 0 - COMPARE CHANNEL
      2. 16.4.2 CHANNEL 1—CAPTURE CHANNEL
    5. 16.5 RTC Registers
  19. 17Low Power Comparator (SYS0)
    1. 17.1 Introduction
    2. 17.2 Block Diagram
    3. 17.3 Functional Description
      1. 17.3.1 Input Selection
      2. 17.3.2 Voltage Divider
      3. 17.3.3 Hysteresis
      4. 17.3.4 Wake-Up
    4. 17.4 SYS0 Registers
  20. 18Battery Monitor, Temperature Sensor, and DCDC Controller (PMUD)
    1. 18.1 Introduction
    2. 18.2 Functional Description
      1. 18.2.1 BATMON
      2. 18.2.2 DCDC
    3. 18.3 PMUD Registers
  21. 19Micro Direct Memory Access (µDMA)
    1. 19.1 Introduction
    2. 19.2 Block Diagram
    3. 19.3 Functional Description
      1. 19.3.1  Channel Assignments
      2. 19.3.2  Priority
      3. 19.3.3  Arbitration Size
      4. 19.3.4  Request Types
        1. 19.3.4.1 Single Request
        2. 19.3.4.2 Burst Request
      5. 19.3.5  Channel Configuration
      6. 19.3.6  Transfer Modes
        1. 19.3.6.1 Stop Mode
        2. 19.3.6.2 Basic Mode
        3. 19.3.6.3 Auto Mode
        4. 19.3.6.4 Ping-Pong Mode
        5. 19.3.6.5 Memory Scatter-Gather Mode
        6. 19.3.6.6 Peripheral Scatter-Gather Mode
      7. 19.3.7  Transfer Size and Increments
      8. 19.3.8  Peripheral Interface
      9. 19.3.9  Software Request
      10. 19.3.10 Interrupts and Errors
      11. 19.3.11 Initialization and Configuration
        1. 19.3.11.1 Module Initialization
        2. 19.3.11.2 Configuring a Memory-to-Memory Transfer
        3. 19.3.11.3 Configure the Channel Attributes
        4. 19.3.11.4 Configure the Channel Control Structure
        5. 19.3.11.5 Start the Transfer
        6. 19.3.11.6 Software Considerations
    4. 19.4 DMA Registers
  22. 20Advanced Encryption Standard (AES)
    1. 20.1 Introduction
      1. 20.1.1 AES Performance
    2. 20.2 Functional Description
      1. 20.2.1 Reset Considerations
      2. 20.2.2 Interrupt and Event Support
        1. 20.2.2.1 Interrupt Events and Requests
        2. 20.2.2.2 Connection to Event Fabric
      3. 20.2.3 µDMA
        1. 20.2.3.1 µDMA Example
    3. 20.3 Encryption and Decryption Configuration
      1. 20.3.1  CBC-MAC (Cipher Block Chaining-Message Authentication Code)
      2. 20.3.2  CBC (Cipher Block Chaining) Encryption
      3. 20.3.3  CBC Decryption
      4. 20.3.4  CTR (Counter) Encryption/Decryption
      5. 20.3.5  ECB (Electronic Code Book) Encryption
      6. 20.3.6  ECB Decryption
      7. 20.3.7  CFB (Cipher Feedback) Encryption
      8. 20.3.8  CFB Decryption
      9. 20.3.9  OFB (Open Feedback) Encryption
      10. 20.3.10 OFB Decryption
      11. 20.3.11 PCBC (Propagating Cipher Block Chaining) Encryption
      12. 20.3.12 PCBC Decryption
      13. 20.3.13 CTR-DRBG (Counter-Deterministic Random Bit Generator)
      14. 20.3.14 CCM
    4. 20.4 AES Registers
  23. 21Analog to Digital Converter (ADC)
    1. 21.1 Overview
    2. 21.2 Block Diagram
    3. 21.3 Functional Description
      1. 21.3.1  ADC Core
      2. 21.3.2  Voltage Reference Options
      3. 21.3.3  Resolution Modes
      4. 21.3.4  ADC Clocking
      5. 21.3.5  Power Down Behavior
      6. 21.3.6  Sampling Trigger Sources and Sampling Modes
        1. 21.3.6.1 AUTO Sampling Mode
        2. 21.3.6.2 MANUAL Sampling Mode
      7. 21.3.7  Sampling Period
      8. 21.3.8  Conversion Modes
      9. 21.3.9  ADC Data Format
      10. 21.3.10 Status Register
      11. 21.3.11 ADC Events
        1. 21.3.11.1 CPU Interrupt Event Publisher (INT_EVENT0)
        2. 21.3.11.2 Generic Event Publisher (INT_EVENT1)
        3. 21.3.11.3 DMA Trigger Event Publisher (INT_EVENT2)
        4. 21.3.11.4 Generic Event Subscriber
    4. 21.4 Advanced Features
      1. 21.4.1 Window Comparator
      2. 21.4.2 DMA & FIFO Operation
        1. 21.4.2.1 DMA/CPU Operation in Non-FIFO Mode (FIFOEN=0)
        2. 21.4.2.2 DMA/CPU Operation in FIFO Mode (FIFOEN=1)
        3. 21.4.2.3 DMA/CPU Operation Summary Matrix
      3. 21.4.3 Ad-hoc Single Conversion
    5. 21.5 ADC Registers
  24. 22I/O Controller (IOC)
    1. 22.1  Introduction
    2. 22.2  Block Diagram
    3. 22.3  I/O Mapping and Configuration
      1. 22.3.1 Basic I/O Mapping
      2. 22.3.2 Radio GPO
      3. 22.3.3 Pin Mapping
      4. 22.3.4 DTB Muxing
    4. 22.4  Edge Detection
    5. 22.5  GPIO
    6. 22.6  I/O Pins
    7. 22.7  Unused Pins
    8. 22.8  Debug Configuration
    9. 22.9  IOC Registers
    10. 22.10 GPIO Registers
  25. 23Universal Asynchronous Receiver/Transmitter (UART-LIN)
    1. 23.1 Introduction
    2. 23.2 Block Diagram
    3. 23.3 UART Functional Description
      1. 23.3.1 Transmit and Receive Logic
      2. 23.3.2 Baud Rate Generation
      3. 23.3.3 FIFO Operation
        1. 23.3.3.1 FIFO Remapping
      4. 23.3.4 Data Transmission
      5. 23.3.5 Flow Control
      6. 23.3.6 IrDA Encoding and Decoding
      7. 23.3.7 Interrupts
      8. 23.3.8 Loopback Operation
    4. 23.4 UART-LIN Specification
      1. 23.4.1 Break transmission in UART mode
      2. 23.4.2 Break reception in UART mode
      3. 23.4.3 Break/Synch transmission in LIN mode
      4. 23.4.4 Break/Synch reception in LIN mode
      5. 23.4.5 Dormant mode operation
      6. 23.4.6 Wakeup signal generation
      7. 23.4.7 Wakeup signal detection when device is in active/idle modes
      8. 23.4.8 Wakeup signal detection when device is in standby mode
    5. 23.5 Interface to µDMA
    6. 23.6 Initialization and Configuration
    7. 23.7 UART Registers
  26. 24Serial Peripheral Interface (SPI)
    1. 24.1 Overview
      1. 24.1.1 Features
      2. 24.1.2 Block Diagram
    2. 24.2 Signal Description
    3. 24.3 Functional Description
      1. 24.3.1  Clock Control
      2. 24.3.2  FIFO Operation
        1. 24.3.2.1 Transmit FIFO
        2. 24.3.2.2 Repeated Transmit Operation
        3. 24.3.2.3 Receive FIFO
        4. 24.3.2.4 FIFO Flush
      3. 24.3.3  Interrupts
      4. 24.3.4  Data Format
      5. 24.3.5  Delayed Data Sampling
      6. 24.3.6  Chip Select Control
      7. 24.3.7  Command Data Control
      8. 24.3.8  Protocol Descriptions
        1. 24.3.8.1 Motorola SPI Frame Format
        2. 24.3.8.2 Texas Instruments Synchronous Serial Frame Format
        3. 24.3.8.3 MICROWIRE Frame Format
      9. 24.3.9  CRC Configuration
      10. 24.3.10 Auto CRC Functionality
      11. 24.3.11 Auto Header Functionality
      12. 24.3.12 SPI Status
      13. 24.3.13 Debug Halt
    4. 24.4 µDMA Operation
    5. 24.5 Initialization and Configuration
    6. 24.6 SPI Registers
  27. 25Inter-Integrated Circuit (I2C)
    1. 25.1 Introduction
    2. 25.2 Block Diagram
    3. 25.3 Functional Description
      1. 25.3.1 Functional Overview
        1. 25.3.1.1 Start and Stop Conditions
        2. 25.3.1.2 Data Format with 7-Bit Address
        3. 25.3.1.3 Data Validity
        4. 25.3.1.4 Acknowledge
        5. 25.3.1.5 Arbitration
      2. 25.3.2 Available Speed Modes
      3. 25.3.3 Interrupts
        1. 25.3.3.1 I2C Controller Interrupts
        2. 25.3.3.2 I2C Target Interrupts
      4. 25.3.4 Loopback Operation
      5. 25.3.5 Command Sequence Flowcharts
        1. 25.3.5.1 I2C Controller Command Sequences
        2. 25.3.5.2 I2C Target Command Sequences
    4. 25.4 Initialization and Configuration
    5. 25.5 I2C Registers
  28. 26Inter-IC Sound (I2S)
    1. 26.1  Introduction
    2. 26.2  Block Diagram
    3. 26.3  Clock Architecture
    4. 26.4  Signal Descriptions
    5. 26.5  Functional Description
      1. 26.5.1 Pin Configuration
      2. 26.5.2 Serial Format Configuration
      3. 26.5.3 I2S Format Schematic
        1. 26.5.3.1 Register Configuration
      4. 26.5.4 Left-Justified (LJF)
        1. 26.5.4.1 Register Configuration
      5. 26.5.5 Right-Justified (RJF)
        1. 26.5.5.1 Register Configuration
      6. 26.5.6 DSP
        1. 26.5.6.1 Register Configuration
      7. 26.5.7 Clock Configuration
    6. 26.6  Memory Interface
      1. 26.6.1 Sample Word Length
      2. 26.6.2 Padding Mechanism
      3. 26.6.3 Channel Mapping
      4. 26.6.4 Sample Storage in Memory
      5. 26.6.5 DMA Operation
        1. 26.6.5.1 Start-Up
        2. 26.6.5.2 Operation
        3. 26.6.5.3 Shutdown
    7. 26.7  Samplestamp Generator
      1. 26.7.1 Samplestamp Counters
      2. 26.7.2 Start-Up Triggers
      3. 26.7.3 Samplestamp Capture
      4. 26.7.4 Achieving Constant Audio Latency
    8. 26.8  Error Detection
    9. 26.9  Usage
      1. 26.9.1 Start-Up Sequence
      2. 26.9.2 Shutdown Sequence
    10. 26.10 I2S Configuration Guideline
    11. 26.11 I2S Registers
  29. 27CAN-FD
    1. 27.1 Introduction
    2. 27.2 Functions
    3. 27.3 MCAN Subsystem
    4. 27.4 MCAN Functional Description
      1. 27.4.1 Operating Modes
        1. 27.4.1.1 Software Initialization
        2. 27.4.1.2 Normal Operation
        3. 27.4.1.3 CAN FD Operation
        4. 27.4.1.4 Transmitter Delay Compensation
          1. 27.4.1.4.1 Description
          2. 27.4.1.4.2 Transmitter Delay Compensation Measurement
        5. 27.4.1.5 Restricted Operation Mode
        6. 27.4.1.6 Bus Monitoring Mode
        7. 27.4.1.7 Disabled Automatic Retransmission
          1. 27.4.1.7.1 Frame Transmission in DAR Mode
        8. 27.4.1.8 Power Down (Sleep Mode)
          1. 27.4.1.8.1 MCAN Clock Stop and Wake Operations
          2. 27.4.1.8.2 MCAN Debug Suspend Operation
        9. 27.4.1.9 Test Modes
          1. 27.4.1.9.1 External Loop Back Mode
          2. 27.4.1.9.2 Internal Loop Back Mode
      2. 27.4.2 Timestamp Generation
        1. 27.4.2.1 External Timestamp Counter
        2. 27.4.2.2 Block Diagram
      3. 27.4.3 Timeout Counter
      4. 27.4.4 Rx Handling
        1. 27.4.4.1 Acceptance Filtering
          1. 27.4.4.1.1 Range Filter
          2. 27.4.4.1.2 Filter for specific IDs
          3. 27.4.4.1.3 Classic Bit Mask Filter
          4. 27.4.4.1.4 Standard Message ID Filtering
          5. 27.4.4.1.5 Extended Message ID Filtering
        2. 27.4.4.2 Rx FIFOs
          1. 27.4.4.2.1 Rx FIFO Blocking Mode
          2. 27.4.4.2.2 Rx FIFO Overwrite Mode
        3. 27.4.4.3 Dedicated Rx Buffers
          1. 27.4.4.3.1 Rx Buffer Handling
        4. 27.4.4.4 Debug on CAN Support
          1. 27.4.4.4.1 Filtering for Debug Messages
          2. 27.4.4.4.2 Debug Message Handling
      5. 27.4.5 Tx Handling
        1. 27.4.5.1 Transmit Pause
        2. 27.4.5.2 Dedicated Tx Buffers
        3. 27.4.5.3 Tx FIFO
        4. 27.4.5.4 Tx Queue
        5. 27.4.5.5 Mixed Dedicated Tx Buffers / Tx FIFO
        6. 27.4.5.6 Mixed Dedicated Tx Buffers / Tx Queue
        7. 27.4.5.7 Transmit Cancellation
        8. 27.4.5.8 Tx Event Handling
      6. 27.4.6 FIFO Acknowledge Handling
      7. 27.4.7 MCAN Message RAM
        1. 27.4.7.1 Message RAM Configuration
        2. 27.4.7.2 Rx Buffer and FIFO Element
        3. 27.4.7.3 Tx Buffer Element
        4. 27.4.7.4 Tx Event FIFO Element
        5. 27.4.7.5 Standard Message ID Filter Element
        6. 27.4.7.6 Extended Message ID Filter Element
      8. 27.4.8 Interrupt Requests
    5. 27.5 CC27xx MCAN Wrapper
    6. 27.6 MCAN Clock Enable
    7. 27.7 Additional Notes
    8. 27.8 CANFD Registers
  30. 28Radio
    1. 28.1  Introduction
    2. 28.2  Block Diagram
    3. 28.3  Overview
      1. 28.3.1 Radio Sub-Domains
      2. 28.3.2 Radio RAMs
      3. 28.3.3 Doorbell (DBELL)
        1. 28.3.3.1 Interrupts
        2. 28.3.3.2 GPIO Control
        3. 28.3.3.3 SYSTIM Interface
    4. 28.4  Radio Usage Model
      1. 28.4.1 CRC and Whitening
    5. 28.5  LRFDDBELL Registers
    6. 28.6  LRFDMDM32 Registers
    7. 28.7  LRFDPBE Registers
    8. 28.8  LRFDPBE32 Registers
    9. 28.9  LRFDRFE Registers
    10. 28.10 LRFDRFE32 Registers
    11. 28.11 LRFDRXF Registers
    12. 28.12 LRFDS2R Registers
    13. 28.13 LRFDTRC Registers
    14. 28.14 LRFDTXF Registers
  31. 29Revision History

4.1.7.2 Exception Return

An exception return occurs when the processor is in Handler mode and execution of one of the following instructions attempts to set the PC to an EXC_RETURN value:

  • A POP or LDM instruction that loads the PC
  • An LDR instruction that loads the PC
  • A BX instruction using any register
The processor saves an EXC_RETURN value to the LR on exception entry. The exception mechanism relies on this value to detect when the processor has completed an exception handler. When the processor loads a value matching this pattern to the PC it detects that the operation is not a normal branch operation and, instead, that the exception is complete. As a result, it starts the exception return sequence. Bits[6:0] of the EXC_RETURN value indicate the required return stack, processor mode, Security state, and stack frame as shown in Table 4-4.

Table 4-4 Exception Return Behavior
Bits

Name

Description

[31:24]

PREFIX

Indicates that this is an EXC_RETURN value. This field reads as 0b11111111
[23:7]

-

Reserved, RES1

[6]

S

Indicates whether registers have been pushed to a Secure or Non-secure stack.

0: Non-secure stack used

1: Secure stack used.

[5]

DCRS

Indicates whether the default stacking rules apply, or whether the called registers are already on the stack.

0: Stacking of the called saved registers is skipped

1: Default rules for stacking the called registers are followed

[4]

FType

In a PE with the Main and Floating-point Extensions:

0: The PE allocated space on the stack for FP context

1: The PE did not allocate space on the stack for FP context.

In a PE without the Floating-point Extension, this bit is Reserved, RES1

[3]

Mode

Indicates the mode that was stacked from.

0: Handler mode

1: Thread mode

[2]

SPSEL

Indicates which stack contains the exception stack frame.

0: Main stack pointer

1: Process stack pointer

[1]

-

Reserved, RES0

[0]

ES

Indicates the Security state the exception was taken to.

0: Non-secure

1: Secure