SLAU846B June   2023  – November 2024 MSPM0G1105 , MSPM0G1106 , MSPM0G1107 , MSPM0G1505 , MSPM0G1506 , MSPM0G1507 , MSPM0G1519 , MSPM0G3105 , MSPM0G3105-Q1 , MSPM0G3106 , MSPM0G3106-Q1 , MSPM0G3107 , MSPM0G3107-Q1 , MSPM0G3505 , MSPM0G3505-Q1 , MSPM0G3506 , MSPM0G3506-Q1 , MSPM0G3507 , MSPM0G3507-Q1 , MSPM0G3519

 

  1.   1
  2.   Read This First
    1.     About This Manual
    2.     Notational Conventions
    3.     Glossary
    4.     Support Resources
    5.     Trademarks
  3. 1 Architecture
    1. 1.1 Architecture Overview
    2. 1.2 Bus Organization
    3. 1.3 Platform Memory Map
      1. 1.3.1 Code Region
      2. 1.3.2 SRAM Region
      3. 1.3.3 Peripheral Region
      4. 1.3.4 Subsystem Region
      5. 1.3.5 System PPB Region
    4. 1.4 Boot Configuration
      1. 1.4.1 Configuration Memory (NONMAIN)
        1. 1.4.1.1 CRC-Backed Configuration Data
        2. 1.4.1.2 16-bit Pattern Match for Critical Fields
      2. 1.4.2 Boot Configuration Routine (BCR)
        1. 1.4.2.1 Serial Wire Debug Related Policies
          1. 1.4.2.1.1 SWD Security Level 0
          2. 1.4.2.1.2 SWD Security Level 1
          3. 1.4.2.1.3 SWD Security Level 2
        2. 1.4.2.2 SWD Mass Erase and Factory Reset Commands
        3. 1.4.2.3 Flash Memory Protection and Integrity Related Policies
          1. 1.4.2.3.1 Locking the Application (MAIN) Flash Memory
          2. 1.4.2.3.2 Locking the Configuration (NONMAIN) Flash Memory
          3. 1.4.2.3.3 Static Write Protection NONMAIN Fields
        4. 1.4.2.4 Application CRC Verification
        5. 1.4.2.5 Fast Boot
        6. 1.4.2.6 Bootstrap Loader (BSL) Enable/Disable Policy
          1. 1.4.2.6.1 BSL Enable
      3. 1.4.3 Bootstrap Loader (BSL)
        1. 1.4.3.1 GPIO Invoke
        2. 1.4.3.2 Bootstrap Loader (BSL) Security Policies
          1. 1.4.3.2.1 BSL Access Password
          2. 1.4.3.2.2 BSL Read-out Policy
          3. 1.4.3.2.3 BSL Security Alert Policy
        3. 1.4.3.3 Application Version
        4. 1.4.3.4 BSL Triggered Mass Erase and Factory Reset
    5. 1.5 NONMAIN_G350x_G310x_G150x_G110x Registers
    6. 1.6 NONMAIN_G351x_G151x Registers
    7. 1.7 Factory Constants
      1. 1.7.1 FACTORYREGION Registers
  4. 2 PMCU
    1. 2.1 PMCU Overview
      1. 2.1.1 Power Domains
      2. 2.1.2 Operating Modes
        1. 2.1.2.1 RUN Mode
        2. 2.1.2.2 SLEEP Mode
        3. 2.1.2.3 STOP Mode
        4. 2.1.2.4 STANDBY Mode
        5. 2.1.2.5 SHUTDOWN Mode
        6. 2.1.2.6 Supported Functionality by Operating Mode
        7. 2.1.2.7 Suspended Low-Power Mode Operation
    2. 2.2 Power Management (PMU)
      1. 2.2.1 Power Supply
      2. 2.2.2 Core Regulator
      3. 2.2.3 Supply Supervisors
        1. 2.2.3.1 Power-on Reset (POR) Supervisor
        2. 2.2.3.2 Brownout Reset (BOR) Supervisor
        3. 2.2.3.3 POR and BOR Behavior During Supply Changes
      4. 2.2.4 Bandgap Reference
      5. 2.2.5 Temperature Sensor
      6. 2.2.6 VBOOST for Analog Muxes
      7. 2.2.7 Peripheral Power Enable Control
        1. 2.2.7.1 Automatic Peripheral Disable in Low Power Modes
    3. 2.3 Clock Module (CKM)
      1. 2.3.1 Oscillators
        1. 2.3.1.1 Internal Low-Frequency Oscillator (LFOSC)
        2. 2.3.1.2 Internal System Oscillator (SYSOSC)
          1. 2.3.1.2.1 SYSOSC Gear Shift
          2. 2.3.1.2.2 SYSOSC Frequency and User Trims
          3. 2.3.1.2.3 SYSOSC Frequency Correction Loop
            1. 2.3.1.2.3.1 SYSOSC FCL in External Resistor Mode (ROSC)
            2. 2.3.1.2.3.2 SYSOSC FCL in Internal Resistor Mode
          4. 2.3.1.2.4 SYSOSC User Trim Procedure
          5. 2.3.1.2.5 Disabling SYSOSC
        3. 2.3.1.3 System Phase-Locked Loop (SYSPLL)
          1. 2.3.1.3.1 Configuring SYSPLL Output Frequencies
          2. 2.3.1.3.2 Loading SYSPLL Lookup Parameters
          3. 2.3.1.3.3 SYSPLL Startup Time
        4. 2.3.1.4 Low Frequency Crystal Oscillator (LFXT)
        5. 2.3.1.5 LFCLK_IN (Digital Clock)
        6. 2.3.1.6 High Frequency Crystal Oscillator (HFXT)
        7. 2.3.1.7 HFCLK_IN (Digital clock)
      2. 2.3.2 Clocks
        1. 2.3.2.1  MCLK (Main Clock) Tree
        2. 2.3.2.2  CPUCLK (Processor Clock)
        3. 2.3.2.3  ULPCLK (Low-Power Clock)
        4. 2.3.2.4  MFCLK (Middle Frequency Clock)
        5. 2.3.2.5  MFPCLK (Middle Frequency Precision Clock)
        6. 2.3.2.6  LFCLK (Low-Frequency Clock)
        7. 2.3.2.7  HFCLK (High-Frequency External Clock)
        8. 2.3.2.8  HSCLK (High Speed Clock)
        9. 2.3.2.9  ADCCLK (ADC Sample Period Clock)
        10. 2.3.2.10 CANCLK (CAN-FD Functional Clock)
        11. 2.3.2.11 RTCCLK (RTC Clock)
        12. 2.3.2.12 External Clock Output (CLK_OUT)
        13. 2.3.2.13 Direct Clock Connections for Infrastructure
      3. 2.3.3 Clock Tree
        1. 2.3.3.1 Peripheral Clock Source Selection
      4. 2.3.4 Clock Monitors
        1. 2.3.4.1 LFCLK Monitor
        2. 2.3.4.2 MCLK Monitor
        3. 2.3.4.3 Startup Monitors
          1. 2.3.4.3.1 LFOSC Startup Monitor
          2. 2.3.4.3.2 LFXT Startup Monitor
          3. 2.3.4.3.3 HFCLK Startup Monitor
          4. 2.3.4.3.4 SYSPLL Startup Monitor
          5. 2.3.4.3.5 HSCLK Status
      5. 2.3.5 Frequency Clock Counter (FCC)
        1. 2.3.5.1 Using the FCC
        2. 2.3.5.2 FCC Frequency Computation and Accuracy
    4. 2.4 System Controller (SYSCTL)
      1. 2.4.1  Resets and Device Initialization
        1. 2.4.1.1 Reset Levels
          1. 2.4.1.1.1 Power-on Reset (POR) Reset Level
          2. 2.4.1.1.2 Brownout Reset (BOR) Reset Level
          3. 2.4.1.1.3 Boot Reset (BOOTRST) Reset Level
          4. 2.4.1.1.4 System Reset (SYSRST) Reset Level
          5. 2.4.1.1.5 CPU-only Reset (CPURST) Reset Level
        2. 2.4.1.2 Initial Conditions After POR
        3. 2.4.1.3 NRST Pin
        4. 2.4.1.4 SWD Pins
        5. 2.4.1.5 Generating Resets in Software
        6. 2.4.1.6 Reset Cause
        7. 2.4.1.7 Peripheral Reset Control
        8. 2.4.1.8 Boot Fail Handling
      2. 2.4.2  Operating Mode Selection
      3. 2.4.3  Asynchronous Fast Clock Requests
      4. 2.4.4  SRAM Write Protection
      5. 2.4.5  Flash Wait States
      6. 2.4.6  Flash Bank Address Swap
      7. 2.4.7  Shutdown Mode Handling (if present)
      8. 2.4.8  Configuration Lockout
      9. 2.4.9  System Status
      10. 2.4.10 Error Handling
      11. 2.4.11 SYSCTL Events
        1. 2.4.11.1 CPU Interrupt Event (CPU_INT)
        2. 2.4.11.2 Nonmaskable Interrupt Event (NMI)
    5. 2.5 Quick Start Reference
      1. 2.5.1 Default Device Configuration
      2. 2.5.2 Leveraging MFCLK
      3. 2.5.3 Optimizing Power Consumption in STOP Mode
      4. 2.5.4 Optimizing Power Consumption in STANDBY Mode
      5. 2.5.5 Increasing MCLK and ULPCLK Precision
      6. 2.5.6 Configuring MCLK for Maximum Speed
      7. 2.5.7 High Speed Clock (SYSPLL, HFCLK) Handling in Low-Power Modes
      8. 2.5.8 Optimizing for Lowest Wakeup Latency
      9. 2.5.9 Optimizing for Lowest Peak Current in RUN/SLEEP Mode
    6. 2.6 SYSCTL_G350x_G310x_G150x_G110x Registers
    7. 2.7 SYSCTL_G351x_G151x Registers
  5. 3 CPU
    1. 3.1 Overview
    2. 3.2 Arm Cortex-M0+ CPU
      1. 3.2.1 CPU Register File
      2. 3.2.2 Stack Behavior
      3. 3.2.3 Execution Modes and Privilege Levels
      4. 3.2.4 Address Space and Supported Data Sizes
    3. 3.3 Interrupts and Exceptions
      1. 3.3.1 Peripheral Interrupts (IRQs)
        1. 3.3.1.1 Nested Vectored Interrupt Controller (NVIC)
        2. 3.3.1.2 Interrupt Groups
        3. 3.3.1.3 Wake Up Controller (WUC)
      2. 3.3.2 Interrupt and Exception Table
      3. 3.3.3 Processor Lockup Scenario
    4. 3.4 CPU Peripherals
      1. 3.4.1 System Control Block (SCB)
      2. 3.4.2 System Tick Timer (SysTick)
      3. 3.4.3 Memory Protection Unit (MPU)
    5. 3.5 Read-Only Memory (ROM)
    6. 3.6 CPUSS Registers
    7. 3.7 WUC Registers
  6. 4 SECURITY
    1. 4.1 Overview
      1. 4.1.1 Secure Boot
      2. 4.1.2 Customer Secure Code (CSC)
    2. 4.2 Boot and Startup Sequence
      1. 4.2.1 CSC Programming Overview
    3. 4.3 Secure Key Storage
    4. 4.4 Flash Memory Protection
      1. 4.4.1 Bank Swapping
      2. 4.4.2 Write Protection
      3. 4.4.3 Read-Execute Protection
      4. 4.4.4 IP Protection
      5. 4.4.5 Data Bank Protection
      6. 4.4.6 Hardware Monotonic Counter
    5. 4.5 SRAM Protection
    6. 4.6 SECURITY Registers
  7. 5 DMA
    1. 5.1 DMA Overview
    2. 5.2 DMA Operation
      1. 5.2.1  Addressing Modes
      2. 5.2.2  Channel Types
      3. 5.2.3  Transfer Modes
        1. 5.2.3.1 Single Transfer
        2. 5.2.3.2 Block Transfer
        3. 5.2.3.3 Repeated Single Transfer
        4. 5.2.3.4 Repeated Block Transfer
        5. 5.2.3.5 Stride Mode
      4. 5.2.4  Extended Modes
        1. 5.2.4.1 Fill Mode
        2. 5.2.4.2 Table Mode
      5. 5.2.5  Initiating DMA Transfers
      6. 5.2.6  Stopping DMA Transfers
      7. 5.2.7  Channel Priorities
      8. 5.2.8  Burst Block Mode
      9. 5.2.9  Using DMA with System Interrupts
      10. 5.2.10 DMA Controller Interrupts
      11. 5.2.11 DMA Trigger Event Status
      12. 5.2.12 DMA Operating Mode Support
        1. 5.2.12.1 Transfer in RUN Mode
        2. 5.2.12.2 Transfer in SLEEP Mode
        3. 5.2.12.3 Transfer in STOP Mode
        4. 5.2.12.4 Transfers in STANDBY Mode
      13. 5.2.13 DMA Address and Data Errors
      14. 5.2.14 Interrupt and Event Support
    3. 5.3 DMA Registers
  8. 6 MATHACL
    1. 6.1 Overview
    2. 6.2 Data Format
      1. 6.2.1 Unsigned 32-bit integers
      2. 6.2.2 Signed 32-bit integers
      3. 6.2.3 Unsigned 32-bit numbers
      4. 6.2.4 Signed 32-bit numbers
    3. 6.3 Basic Operation
    4. 6.4 Configuration Details with Examples
      1. 6.4.1 Sine and Cosine (SINCOS)
      2. 6.4.2 Arc Tangent (ATAN2)
      3. 6.4.3 Square Root (SQRT)
      4. 6.4.4 Division (DIV)
      5. 6.4.5 Multiplication
        1. 6.4.5.1 Multiply32 (MPY32)
        2. 6.4.5.2 Square32 (SQUARE32)
        3. 6.4.5.3 Multiply64 (MPY64)
        4. 6.4.5.4 Square64 (SQUARE64)
      6. 6.4.6 Multiply-Accumulate (MAC)
      7. 6.4.7 Square Accumulate (SAC)
    5. 6.5 MATHACL Registers
    6. 6.6 DMA Support for Accumulation Functions
  9. 7 NVM (Flash)
    1. 7.1 NVM Overview
      1. 7.1.1 Key Features
      2. 7.1.2 System Components
      3. 7.1.3 Terminology
    2. 7.2 Flash Memory Bank Organization
      1. 7.2.1 Banks
      2. 7.2.2 Flash Memory Regions
      3. 7.2.3 Addressing
        1. 7.2.3.1 Flash Memory Map
      4. 7.2.4 Memory Organization Examples
    3. 7.3 Flash Controller
      1. 7.3.1 Overview of Flash Controller Commands
      2. 7.3.2 NOOP Command
      3. 7.3.3 PROGRAM Command
        1. 7.3.3.1 Program Bit Masking Behavior
        2. 7.3.3.2 Programming Less Than One Flash Word
        3. 7.3.3.3 Target Data Alignment (Devices with Single Flash Word Programming Only)
        4. 7.3.3.4 Target Data Alignment (Devices With Multiword Programming)
        5. 7.3.3.5 Executing a PROGRAM Operation
      4. 7.3.4 ERASE Command
        1. 7.3.4.1 Erase Sector Masking Behavior
        2. 7.3.4.2 Executing an ERASE Operation
      5. 7.3.5 READVERIFY Command
        1. 7.3.5.1 Executing a READVERIFY Operation
      6. 7.3.6 BLANKVERIFY Command
        1. 7.3.6.1 Executing a BLANKVERIFY Operation
      7. 7.3.7 Command Diagnostics
        1. 7.3.7.1 Command Status
        2. 7.3.7.2 Address Translation
        3. 7.3.7.3 Pulse Counts
      8. 7.3.8 Overriding the System Address With a Bank ID, Region ID, and Bank Address
      9. 7.3.9 FLASHCTL Events
        1. 7.3.9.1 CPU Interrupt Event Publisher
    4. 7.4 Write Protection
      1. 7.4.1 Write Protection Resolution
      2. 7.4.2 Static Write Protection
      3. 7.4.3 Dynamic Write Protection
        1. 7.4.3.1 Configuring Protection for the MAIN Region
        2. 7.4.3.2 Configuring Protection for the NONMAIN Region
    5. 7.5 Read Interface
      1. 7.5.1 Bank Address Swapping
      2. 7.5.2 ECC Error Handling
        1. 7.5.2.1 Single bit (correctable) errors
        2. 7.5.2.2 Dual bit (uncorrectable) errors
    6. 7.6 FLASHCTL_G350x_G310x_G150x_G110x Registers
    7. 7.7 FLASHCTL_G351x_G151x Registers
  10. 8 Events
    1. 8.1 Events Overview
      1. 8.1.1 Event Publisher
      2. 8.1.2 Event Subscriber
      3. 8.1.3 Event Fabric Routing
        1. 8.1.3.1 CPU Interrupt Event Route (CPU_INT)
        2. 8.1.3.2 DMA Trigger Event Route (DMA_TRIGx)
        3. 8.1.3.3 Generic Event Route (GEN_EVENTx)
      4. 8.1.4 Event Routing Map
      5. 8.1.5 Event Propagation Latency
    2. 8.2 Events Operation
      1. 8.2.1 CPU Interrupt
      2. 8.2.2 DMA Trigger
      3. 8.2.3 Peripheral to Peripheral Event
      4. 8.2.4 Extended Module Description Register
      5. 8.2.5 Using Event Registers
        1. 8.2.5.1 Event Registers
        2. 8.2.5.2 Configuring Events
        3. 8.2.5.3 Responding to CPU Interrupts in Application Software
        4. 8.2.5.4 Hardware Event Handling
  11. 9 Low Frequency Subsystem (LFSS)
    1. 9.1 Overview
    2. 9.2 Clock System
    3. 9.3 LFSS Reset
    4. 9.4 Real Time Counter (RTC_x)
    5. 9.5 Independent Watchdog Timer (IWDT)
    6. 9.6 Scratchpad Memory
    7. 9.7 Lock Function of RTC and WDT
    8. 9.8 LFSS Registers
  12. 10IOMUX
    1. 10.1 IOMUX Overview
      1. 10.1.1 IO Types and Analog Sharing
    2. 10.2 IOMUX Operation
      1. 10.2.1 Peripheral Function (PF) Assignment
      2. 10.2.2 Logic High to Hi-Z Conversion
      3. 10.2.3 Logic Inversion
      4. 10.2.4 SHUTDOWN Mode Wakeup Logic
      5. 10.2.5 Pullup/Pulldown Resistors
      6. 10.2.6 Drive Strength Control
      7. 10.2.7 Hysteresis and Logic Level Control
    3. 10.3 IOMUX Registers
  13. 11GPIO
    1. 11.1 GPIO Overview
    2. 11.2 GPIO Operation
      1. 11.2.1 GPIO Ports
      2. 11.2.2 GPIO Read/Write Interface
      3. 11.2.3 GPIO Input Glitch Filtering and Synchronization
      4. 11.2.4 GPIO Fast Wake
      5. 11.2.5 GPIO DMA Interface
      6. 11.2.6 Event Publishers and Subscribers
    3. 11.3 GPIO Registers
  14. 12ADC
    1. 12.1 ADC Overview
    2. 12.2 ADC Operation
      1. 12.2.1  ADC Core
      2. 12.2.2  Voltage Reference Options
      3. 12.2.3  Generic Resolution Modes
      4. 12.2.4  Hardware Averaging
      5. 12.2.5  ADC Clocking
      6. 12.2.6  Common ADC Use Cases
      7. 12.2.7  Power Down Behavior
      8. 12.2.8  Sampling Trigger Sources and Sampling Modes
        1. 12.2.8.1 AUTO Sampling Mode
        2. 12.2.8.2 MANUAL Sampling Mode
      9. 12.2.9  Sampling Period
      10. 12.2.10 Conversion Modes
      11. 12.2.11 Data Format
      12. 12.2.12 Advanced Features
        1. 12.2.12.1 Simultaneous Sampling
        2. 12.2.12.2 Window Comparator
        3. 12.2.12.3 DMA and FIFO Operation
        4. 12.2.12.4 Analog Peripheral Interconnection
      13. 12.2.13 Status Register
      14. 12.2.14 ADC Events
        1. 12.2.14.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 12.2.14.2 Generic Event Publisher (GEN_EVENT)
        3. 12.2.14.3 DMA Trigger Event Publisher (DMA_TRIG)
        4. 12.2.14.4 Generic Event Subscriber (FSUB_0)
    3. 12.3 ADC12 Registers
  15. 13COMP
    1. 13.1 Comparator Overview
    2. 13.2 Comparator Operation
      1. 13.2.1  Comparator Configuration
      2. 13.2.2  Comparator Channels Selection
      3. 13.2.3  Comparator Output
      4. 13.2.4  Output Filter
      5. 13.2.5  Sampled Output Mode
      6. 13.2.6  Blanking Mode
      7. 13.2.7  Reference Voltage Generator
      8. 13.2.8  Window Comparator Mode
      9. 13.2.9  Comparator Hysteresis
      10. 13.2.10 Input SHORT Switch
      11. 13.2.11 Interrupt and Events Support
        1. 13.2.11.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 13.2.11.2 Generic Event Publisher (GEN_EVENT)
        3. 13.2.11.3 Generic Event Subscribers
    3. 13.3 COMP Registers
  16. 14OPA
    1. 14.1 OPA Overview
    2. 14.2 OPA Operation
      1. 14.2.1 Analog Core
      2. 14.2.2 Power Up Behavior
      3. 14.2.3 Inputs
      4. 14.2.4 Output
      5. 14.2.5 Clock Requirements
      6. 14.2.6 Chopping
      7. 14.2.7 OPA Amplifier Modes
        1. 14.2.7.1 General-Purpose Mode
        2. 14.2.7.2 Buffer Mode
        3. 14.2.7.3 OPA PGA Mode
          1. 14.2.7.3.1 Inverting PGA Mode
          2. 14.2.7.3.2 Non-inverting PGA Mode
        4. 14.2.7.4 Difference Amplifier Mode
        5. 14.2.7.5 Cascade Amplifier Mode
      8. 14.2.8 OPA Configuration Selection
      9. 14.2.9 Burnout Current Source
    3. 14.3 OA Registers
  17. 15GPAMP
    1. 15.1 GPAMP Overview
    2. 15.2 GPAMP Operation
      1. 15.2.1 Analog Core
      2. 15.2.2 Power Up Behavior
      3. 15.2.3 Inputs
      4. 15.2.4 Output
      5. 15.2.5 GPAMP Amplifier Modes
        1. 15.2.5.1 General-Purpose Mode
        2. 15.2.5.2 ADC Buffer Mode
        3. 15.2.5.3 Unity Gain Mode
      6. 15.2.6 Chopping
    3. 15.3 GPAMP Registers
  18. 16DAC
    1. 16.1 DAC Introduction
    2. 16.2 DAC Operation
      1. 16.2.1  DAC Core
      2. 16.2.2  DAC Output
      3. 16.2.3  DAC Voltage Reference
      4. 16.2.4  DAC Output Buffers
      5. 16.2.5  DAC Data Formats
      6. 16.2.6  Sample Time Generator
      7. 16.2.7  DAC FIFO Structure
        1. 16.2.7.1 Loading Data From FIFO to Internal DAC Data Register
      8. 16.2.8  DAC Operation With DMA Controller
        1. 16.2.8.1 DMA Trigger Interface
        2. 16.2.8.2 DMA Status Interface
        3. 16.2.8.3 DMA Trigger Generation Scheme
      9. 16.2.9  DAC Operation With CPU
        1. 16.2.9.1 Interrupt conditions for DAC operation with CPU
      10. 16.2.10 Data Register Format
      11. 16.2.11 DAC Output Amplifier Offset Calibration
      12. 16.2.12 Interrupt and Event Support
        1. 16.2.12.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 16.2.12.2 Generic Event Publisher (GEN_EVENT)
        3. 16.2.12.3 DMA Trigger Event Publisher
        4. 16.2.12.4 Generic Event Subscriber (FSUB_0)
    3. 16.3 DAC12 Registers
  19. 17VREF
    1. 17.1 VREF Overview
    2. 17.2 VREF Operation
      1. 17.2.1 Internal Reference Generation
      2. 17.2.2 External Reference Input
      3. 17.2.3 Analog Peripheral Interface
    3. 17.3 VREF Registers
  20. 18UART
    1. 18.1 UART Overview
      1. 18.1.1 Purpose of the Peripheral
      2. 18.1.2 Features
      3. 18.1.3 Functional Block Diagram
    2. 18.2 UART Operation
      1. 18.2.1 Clock Control
      2. 18.2.2 Signal Descriptions
      3. 18.2.3 General Architecture and Protocol
        1. 18.2.3.1  Transmit Receive Logic
        2. 18.2.3.2  Bit Sampling
        3. 18.2.3.3  Majority Voting Feature
        4. 18.2.3.4  Baud Rate Generation
        5. 18.2.3.5  Data Transmission
        6. 18.2.3.6  Error and Status
        7. 18.2.3.7  Local Interconnect Network (LIN) Support
          1. 18.2.3.7.1 LIN Responder Transmission Delay
        8. 18.2.3.8  Flow Control
        9. 18.2.3.9  Idle-Line Multiprocessor
        10. 18.2.3.10 9-Bit UART Mode
        11. 18.2.3.11 RS485 Support
        12. 18.2.3.12 DALI Protocol
        13. 18.2.3.13 Manchester Encoding and Decoding
        14. 18.2.3.14 IrDA Encoding and Decoding
        15. 18.2.3.15 ISO7816 Smart Card Support
        16. 18.2.3.16 Address Detection
        17. 18.2.3.17 FIFO Operation
        18. 18.2.3.18 Loopback Operation
        19. 18.2.3.19 Glitch Suppression
      4. 18.2.4 Low Power Operation
      5. 18.2.5 Reset Considerations
      6. 18.2.6 Initialization
      7. 18.2.7 Interrupt and Events Support
        1. 18.2.7.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 18.2.7.2 DMA Trigger Publisher (DMA_TRIG_RX, DMA_TRIG_TX)
      8. 18.2.8 Emulation Modes
    3. 18.3 UART Registers
  21. 19SPI
    1. 19.1 SPI Overview
      1. 19.1.1 Purpose of the Peripheral
      2. 19.1.2 Features
      3. 19.1.3 Functional Block Diagram
      4. 19.1.4 External Connections and Signal Descriptions
    2. 19.2 SPI Operation
      1. 19.2.1 Clock Control
      2. 19.2.2 General Architecture
        1. 19.2.2.1 Chip Select and Command Handling
          1. 19.2.2.1.1 Chip Select Control
          2. 19.2.2.1.2 Command Data Control
        2. 19.2.2.2 Data Format
        3. 19.2.2.3 Delayed data sampling
        4. 19.2.2.4 Clock Generation
        5. 19.2.2.5 FIFO Operation
        6. 19.2.2.6 Loopback mode
        7. 19.2.2.7 DMA Operation
        8. 19.2.2.8 Repeat Transfer mode
        9. 19.2.2.9 Low Power Mode
      3. 19.2.3 Protocol Descriptions
        1. 19.2.3.1 Motorola SPI Frame Format
        2. 19.2.3.2 Texas Instruments Synchronous Serial Frame Format
      4. 19.2.4 Reset Considerations
      5. 19.2.5 Initialization
      6. 19.2.6 Interrupt and Events Support
        1. 19.2.6.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 19.2.6.2 DMA Trigger Publisher (DMA_TRIG_RX, DMA_TRIG_TX)
      7. 19.2.7 Emulation Modes
    3. 19.3 SPI Registers
  22. 20I2C
    1. 20.1 I2C Overview
      1. 20.1.1 Purpose of the Peripheral
      2. 20.1.2 Features
      3. 20.1.3 Functional Block Diagram
      4. 20.1.4 Environment and External Connections
    2. 20.2 I2C Operation
      1. 20.2.1 Clock Control
        1. 20.2.1.1 Clock Select and I2C Speed
        2. 20.2.1.2 Clock Startup
      2. 20.2.2 Signal Descriptions
      3. 20.2.3 General Architecture
        1. 20.2.3.1  I2C Bus Functional Overview
        2. 20.2.3.2  START and STOP Conditions
        3. 20.2.3.3  Data Format with 7-Bit Address
        4. 20.2.3.4  Acknowledge
        5. 20.2.3.5  Repeated Start
        6. 20.2.3.6  SCL Clock Low Timeout
        7. 20.2.3.7  Clock Stretching
        8. 20.2.3.8  Dual Address
        9. 20.2.3.9  Arbitration
        10. 20.2.3.10 Multiple Controller Mode
        11. 20.2.3.11 Glitch Suppression
        12. 20.2.3.12 FIFO operation
          1. 20.2.3.12.1 Flushing Stale Tx Data in Target Mode
        13. 20.2.3.13 Loopback mode
        14. 20.2.3.14 Burst Mode
        15. 20.2.3.15 DMA Operation
        16. 20.2.3.16 Low-Power Operation
      4. 20.2.4 Protocol Descriptions
        1. 20.2.4.1 I2C Controller Mode
          1. 20.2.4.1.1 Controller Configuration
          2. 20.2.4.1.2 Controller Mode Operation
          3. 20.2.4.1.3 Read On TX Empty
        2. 20.2.4.2 I2C Target Mode
          1. 20.2.4.2.1 Target Mode Operation
      5. 20.2.5 Reset Considerations
      6. 20.2.6 Initialization
      7. 20.2.7 Interrupt and Events Support
        1. 20.2.7.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 20.2.7.2 DMA Trigger Publisher (DMA_TRIG1, DMA_TRIG0)
      8. 20.2.8 Emulation Modes
    3. 20.3 I2C Registers
  23. 21CAN-FD
    1. 21.1 MCAN Overview
      1. 21.1.1 MCAN Features
    2. 21.2 MCAN Environment
    3. 21.3 CAN Network Basics
    4. 21.4 MCAN Functional Description
      1. 21.4.1  Clock Set up
      2. 21.4.2  Module Clocking Requirements
      3. 21.4.3  Interrupt Requests
      4. 21.4.4  Operating Modes
        1. 21.4.4.1 Normal Operation
        2. 21.4.4.2 CAN Classic
        3. 21.4.4.3 CAN FD Operation
      5. 21.4.5  Software Initialization
      6. 21.4.6  Transmitter Delay Compensation
        1. 21.4.6.1 Description
        2. 21.4.6.2 Transmitter Delay Compensation Measurement
      7. 21.4.7  Restricted Operation Mode
      8. 21.4.8  Bus Monitoring Mode
      9. 21.4.9  Disabled Automatic Retransmission (DAR) Mode
        1. 21.4.9.1 Frame Transmission in DAR Mode
      10. 21.4.10 Clock Stop Mode
        1. 21.4.10.1 Suspend Mode
        2. 21.4.10.2 Wakeup Request
      11. 21.4.11 Test Modes
        1. 21.4.11.1 External Loop Back Mode
        2. 21.4.11.2 Internal Loop Back Mode
      12. 21.4.12 Timestamp Generation
        1. 21.4.12.1 External Timestamp Counter
      13. 21.4.13 Timeout Counter
      14. 21.4.14 Safety
        1. 21.4.14.1 ECC Wrapper
        2. 21.4.14.2 ECC Aggregator
          1. 21.4.14.2.1 ECC Aggregator Overview
          2. 21.4.14.2.2 ECC Aggregator Registers
        3. 21.4.14.3 Reads to ECC Control and Status Registers
        4. 21.4.14.4 ECC Interrupts
      15. 21.4.15 Tx Handling
        1. 21.4.15.1 Transmit Pause
        2. 21.4.15.2 Dedicated Tx Buffers
        3. 21.4.15.3 Tx FIFO
        4. 21.4.15.4 Tx Queue
        5. 21.4.15.5 Mixed Dedicated Tx Buffers/Tx FIFO
        6. 21.4.15.6 Mixed Dedicated Tx Buffers/Tx Queue
        7. 21.4.15.7 Transmit Cancellation
        8. 21.4.15.8 Tx Event Handling
        9. 21.4.15.9 FIFO Acknowledge Handling
      16. 21.4.16 Rx Handling
        1. 21.4.16.1 Acceptance Filtering
          1. 21.4.16.1.1 Range Filter
          2. 21.4.16.1.2 Filter for Specific IDs
          3. 21.4.16.1.3 Classic Bit Mask Filter
          4. 21.4.16.1.4 Standard Message ID Filtering
          5. 21.4.16.1.5 Extended Message ID Filtering
      17. 21.4.17 Rx FIFOs
        1. 21.4.17.1 Rx FIFO Blocking Mode
        2. 21.4.17.2 Rx FIFO Overwrite Mode
      18. 21.4.18 Dedicated Rx Buffers
        1. 21.4.18.1 Rx Buffer Handling
      19. 21.4.19 Message RAM
        1. 21.4.19.1 Message RAM Configuration
        2. 21.4.19.2 Rx Buffer and FIFO Element
        3. 21.4.19.3 Tx Buffer Element
        4. 21.4.19.4 Tx Event FIFO Element
        5. 21.4.19.5 Standard Message ID Filter Element
        6. 21.4.19.6 Extended Message ID Filter Element
    5. 21.5 MCAN Integration
    6. 21.6 Interrupt and Event Support
      1. 21.6.1 CPU Interrupt Event Publisher (CPU_INT)
    7. 21.7 MCAN Registers
  24. 22CRC
    1. 22.1 CRC Overview
      1. 22.1.1 CRC16-CCITT
      2. 22.1.2 CRC32-ISO3309
    2. 22.2 CRC Operation
      1. 22.2.1 CRC Generator Implementation
      2. 22.2.2 Configuration
        1. 22.2.2.1 Polynomial Selection
        2. 22.2.2.2 Bit Order
        3. 22.2.2.3 Byte Swap
        4. 22.2.2.4 Byte Order
        5. 22.2.2.5 CRC C Library Compatibility
    3. 22.3 CRCP0 Registers
  25. 23AES
    1. 23.1 AES Overview
      1. 23.1.1 AES Performance
    2. 23.2 AES Operation
      1. 23.2.1 AES Register Access Rules
      2. 23.2.2 Loading the Key
      3. 23.2.3 Loading Data
      4. 23.2.4 Reading Data
      5. 23.2.5 Triggering an Encryption or Decryption
      6. 23.2.6 Single Block Operations
        1. 23.2.6.1 Encryption
        2. 23.2.6.2 Decryption
          1. 23.2.6.2.1 Pregenerating a Decryption Key
      7. 23.2.7 Block Cipher Mode Operations
        1. 23.2.7.1 Electronic Codebook (ECB) Mode
          1. 23.2.7.1.1 ECB Encryption
          2. 23.2.7.1.2 ECB Decryption
        2. 23.2.7.2 Cipher Block Chaining (CBC) Mode
          1. 23.2.7.2.1 CBC Encryption
          2. 23.2.7.2.2 CBC Decryption
        3. 23.2.7.3 Output Feedback (OFB) Mode
          1. 23.2.7.3.1 OFB Encryption
          2. 23.2.7.3.2 OFB Decryption
        4. 23.2.7.4 Cipher Feedback (CFB) Mode
          1. 23.2.7.4.1 CFB Encryption
          2. 23.2.7.4.2 CFB Decryption
        5. 23.2.7.5 Counter (CTR) Mode
          1. 23.2.7.5.1 CTR Encryption
          2. 23.2.7.5.2 CTR Decryption
      8. 23.2.8 AES Events
        1. 23.2.8.1 CPU Interrupt Event Publisher (CPU_EVENT)
        2. 23.2.8.2 DMA Trigger Event Publisher (DMA_TRIG0)
        3. 23.2.8.3 DMA Trigger Event Publisher (DMA_TRIG1)
        4. 23.2.8.4 DMA Trigger Event Publisher (DMA_TRIG2)
    3. 23.3 AES Registers
  26. 24AESADV
    1. 24.1 AESADV Overview
      1. 24.1.1 AESADV Performance
    2. 24.2 AESADV Operation
      1. 24.2.1 Loading the Key
      2. 24.2.2 Writing Input Data
      3. 24.2.3 Reading Output Data
      4. 24.2.4 Operation Descriptions
        1. 24.2.4.1 Single Block Operation
        2. 24.2.4.2 Electronic Codebook (ECB) Mode
          1. 24.2.4.2.1 ECB Encryption
          2. 24.2.4.2.2 ECB Decryption
        3. 24.2.4.3 Cipher Block Chaining (CBC) Mode
          1. 24.2.4.3.1 CBC Encryption
          2. 24.2.4.3.2 CBC Decryption
        4. 24.2.4.4 Output Feedback (OFB) Mode
          1. 24.2.4.4.1 OFB Encryption
          2. 24.2.4.4.2 OFB Decryption
        5. 24.2.4.5 Cipher Feedback (CFB) Mode
          1. 24.2.4.5.1 CFB Encryption
          2. 24.2.4.5.2 CFB Decryption
        6. 24.2.4.6 Counter (CTR) Mode
          1. 24.2.4.6.1 CTR Encryption
          2. 24.2.4.6.2 CTR Decryption
        7. 24.2.4.7 Galois Counter (GCM) Mode
          1. 24.2.4.7.1 GHASH Operation
          2. 24.2.4.7.2 GCM Operating Modes
            1. 24.2.4.7.2.1 Autonomous GCM Operation
              1. 24.2.4.7.2.1.1 GMAC
            2. 24.2.4.7.2.2 GCM With Pre-Calculations
            3. 24.2.4.7.2.3 GCM Operation With Precalculated H- and Y0-Encrypted Forced to Zero
        8. 24.2.4.8 Counter With Cipher Block Chaining Message Authentication Code (CCM)
          1. 24.2.4.8.1 CCM Operation
      5. 24.2.5 AES Events
        1. 24.2.5.1 CPU Interrupt Event Publisher (CPU_EVENT)
        2. 24.2.5.2 DMA Trigger Event Publisher (DMA_TRIG_DATAIN)
        3. 24.2.5.3 DMA Trigger Event Publisher (DMA_TRIG_DATAOUT)
    3. 24.3 AESADV Registers
  27. 25Keystore
    1. 25.1 Overview
    2. 25.2 Detailed Description
    3. 25.3 KEYSTORECTL Registers
  28. 26TRNG
    1. 26.1 TRNG Overview
    2. 26.2 TRNG Operation
      1. 26.2.1 TRNG Generation Data Path
      2. 26.2.2 Clock Configuration and Output Rate
      3. 26.2.3 Behavior in Low Power Modes
      4. 26.2.4 Health Tests
        1. 26.2.4.1 Digital Block Startup Self-Test
        2. 26.2.4.2 Analog Block Startup Self-Test
        3. 26.2.4.3 Runtime Health Test
          1. 26.2.4.3.1 Repetition Count Test
          2. 26.2.4.3.2 Adaptive Proportion Test
          3. 26.2.4.3.3 Handling Runtime Health Test Failures
      5. 26.2.5 Configuration
        1. 26.2.5.1 TRNG State Machine
          1. 26.2.5.1.1 Changing TRNG States
        2. 26.2.5.2 Using the TRNG
        3. 26.2.5.3 TRNG Events
          1. 26.2.5.3.1 CPU Interrupt Event Publisher (CPU_INT)
    3. 26.3 TRNG Registers
  29. 27Timers (TIMx)
    1. 27.1 TIMx Overview
      1. 27.1.1 TIMG Overview
        1. 27.1.1.1 TIMG Features
        2. 27.1.1.2 Functional Block Diagram
      2. 27.1.2 TIMA Overview
        1. 27.1.2.1 TIMA Features
        2. 27.1.2.2 Functional Block Diagram
      3. 27.1.3 TIMx Instance Configuration
    2. 27.2 TIMx Operation
      1. 27.2.1  Timer Counter
        1. 27.2.1.1 Clock Source Select and Prescaler
          1. 27.2.1.1.1 Internal Clock and Prescaler
          2. 27.2.1.1.2 External Signal Trigger
        2. 27.2.1.2 Repeat Counter (TIMA only)
      2. 27.2.2  Counting Mode Control
        1. 27.2.2.1 One-shot and Periodic Modes
        2. 27.2.2.2 Down Counting Mode
        3. 27.2.2.3 Up/Down Counting Mode
        4. 27.2.2.4 Up Counting Mode
        5. 27.2.2.5 Phase Load (TIMA only)
      3. 27.2.3  Capture/Compare Module
        1. 27.2.3.1 Capture Mode
          1. 27.2.3.1.1 Input Selection, Counter Conditions, and Inversion
            1. 27.2.3.1.1.1 CCP Input Edge Synchronization
            2. 27.2.3.1.1.2 CCP Input Pulse Conditions
            3. 27.2.3.1.1.3 Counter Control Operation
            4. 27.2.3.1.1.4 CCP Input Filtering
            5. 27.2.3.1.1.5 Input Selection
          2. 27.2.3.1.2 Use Cases
            1. 27.2.3.1.2.1 Edge Time Capture
            2. 27.2.3.1.2.2 Period Capture
            3. 27.2.3.1.2.3 Pulse Width Capture
            4. 27.2.3.1.2.4 Combined Pulse Width and Period Time
          3. 27.2.3.1.3 QEI Mode (TIMG with QEI support only)
            1. 27.2.3.1.3.1 QEI With 2-Signal
            2. 27.2.3.1.3.2 QEI With Index Input
            3. 27.2.3.1.3.3 QEI Error Detection
          4. 27.2.3.1.4 Hall Input Mode (TIMG with QEI support only)
        2. 27.2.3.2 Compare Mode
          1. 27.2.3.2.1 Edge Count
      4. 27.2.4  Shadow Load and Shadow Compare
        1. 27.2.4.1 Shadow Load (TIMG4-7, TIMA only)
        2. 27.2.4.2 Shadow Compare (TIMG4-7, TIMG12-13, TIMA only)
      5. 27.2.5  Output Generator
        1. 27.2.5.1 Configuration
        2. 27.2.5.2 Use Cases
          1. 27.2.5.2.1 Edge-Aligned PWM
          2. 27.2.5.2.2 Center-Aligned PWM
          3. 27.2.5.2.3 Asymmetric PWM (TIMA only)
          4. 27.2.5.2.4 Complementary PWM With Deadband Insertion (TIMA only)
        3. 27.2.5.3 Forced Output
      6. 27.2.6  Fault Handler (TIMA only)
        1. 27.2.6.1 Fault Input Conditioning
        2. 27.2.6.2 Fault Input Sources
        3. 27.2.6.3 Counter Behavior With Fault Conditions
        4. 27.2.6.4 Output Behavior With Fault Conditions
      7. 27.2.7  Synchronization With Cross Trigger
        1. 27.2.7.1 Main Timer Cross Trigger Configuration
        2. 27.2.7.2 Secondary Timer Cross Trigger Configuration
      8. 27.2.8  Low Power Operation
      9. 27.2.9  Interrupt and Event Support
        1. 27.2.9.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 27.2.9.2 Generic Event Publisher and Subscriber (GEN_EVENT0 and GEN_EVENT1)
        3. 27.2.9.3 Generic Subscriber Event Example (COMP to TIMx)
      10. 27.2.10 Debug Handler (TIMA Only)
    3. 27.3 TIMx Registers
  30. 28RTC
    1. 28.1 Overview
      1. 28.1.1 RTC Instances
    2. 28.2 Basic Operation
    3. 28.3 Configuration
      1. 28.3.1  Clocking
      2. 28.3.2  Reading and Writing to RTC Peripheral Registers
      3. 28.3.3  Binary vs. BCD
      4. 28.3.4  Leap Year Handling
      5. 28.3.5  Calendar Alarm Configuration
      6. 28.3.6  Interval Alarm Configuration
      7. 28.3.7  Periodic Alarm Configuration
      8. 28.3.8  Calibration
        1. 28.3.8.1 Crystal Offset Error
          1. 28.3.8.1.1 Offset Error Correction Mechanism
        2. 28.3.8.2 Crystal Temperature Error
          1. 28.3.8.2.1 Temperature Drift Correction Mechanism
      9. 28.3.9  RTC Prescaler Extension
      10. 28.3.10 RTC Timestamp Capture
      11. 28.3.11 RTC Events
        1. 28.3.11.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 28.3.11.2 Generic Event Publisher (GEN_EVENT)
    4. 28.4 RTC Registers
  31. 29IWDT
    1. 29.1 834
    2. 29.2 IWDT Clock Configuration
    3. 29.3 IWDT Period Selection
    4. 29.4 Debug Behavior of the IWDT
    5. 29.5 IWDT Registers
  32. 30WWDT
    1. 30.1 WWDT Overview
      1. 30.1.1 Watchdog Mode
      2. 30.1.2 Interval Timer Mode
    2. 30.2 WWDT Operation
      1. 30.2.1 Mode Selection
      2. 30.2.2 Clock Configuration
      3. 30.2.3 Low-Power Mode Behavior
      4. 30.2.4 Debug Behavior
      5. 30.2.5 WWDT Events
        1. 30.2.5.1 CPU Interrupt Event Publisher (CPU_INT)
    3. 30.3 WWDT Registers
  33. 31Debug
    1. 31.1 DEBUGSS Overview
      1. 31.1.1 Debug Interconnect
      2. 31.1.2 Physical Interface
      3. 31.1.3 Debug Access Ports
    2. 31.2 DEBUGSS Operation
      1. 31.2.1 Debug Features
        1. 31.2.1.1 Processor Debug
          1. 31.2.1.1.1 Breakpoint Unit (BPU)
          2. 31.2.1.1.2 Data Watchpoint and Trace Unit (DWT)
          3. 31.2.1.1.3 Processor Trace (MTB)
        2. 31.2.1.2 Peripheral Debug
        3. 31.2.1.3 EnergyTrace Technology
      2. 31.2.2 Behavior in Low Power Modes
      3. 31.2.3 Restricting Debug Access
      4. 31.2.4 Mailbox (DSSM)
        1. 31.2.4.1 DSSM Events
          1. 31.2.4.1.1 CPU Interrupt Event (CPU_INT)
    3. 31.3 DEBUGSS Registers
  34. 32Revision History

3.3.1.2 Interrupt Groups

To support mapping of more than 32 peripheral interrupt sources to the NVIC, certain MSPM0 devices include interrupt grouping logic (INT_GROUP) in the MCPUSS to combine several interrupts together to source one native NVIC interrupt.

The INT_GROUP interrupt grouping uses the MSPM0 event management register structure with the key difference being that all peripheral interrupt sources to the interrupt group are always unmasked (always enabled) such that no additional enable configuration is needed beyond the peripheral interrupt configuration and the NVIC configuration. The IMASK register itself is read-only and hardwired to enable all sources to the interrupt group. Figure 3-4 shows the INT_GROUP structure.

Interrupt Group (INT_GROUP) Figure 3-4 Interrupt Group (INT_GROUP)

Because no masking control is required, application software only needs to interface with the interrupt index (IIDX) register to efficiently handle a peripheral interrupt which is registered to the NVIC through an INT_GROUP.

Application software can read the IIDX register in the INT_GROUP to determine and clear the highest priority pending peripheral interrupt in the group. A read to IIDX will return an index corresponding to the highest priority peripheral which set an interrupt. The read action will also simultaneously clear the RIS and MIS bits corresponding to the highest priority interrupt whose index was returned by the read. The value read from the IIDX register can then be used in a case statement, as shown below.

void GROUP_HANDLER(void) 
{
  switch(IIDX)
  {
    case 0:         // no IRQ pending
      break;
    case 1:         // IRQ[0] 
      do_peripheral_1_ISR();
      break;
    case 2:         // IRQ[1] 
      do_peripheral_2_ISR();
      break;
    default:        // out of range 
      illegal();
  }
}

Usage

Because peripheral interrupts that are grouped together into an INT_GROUP source a single NVIC interrupt, it is not possible to have one peripheral interrupt in a group preempt the execution of an active handler for the interrupt group. For example, take the scenario where the WWDT0 interrupt request line and the PMCU interrupt request line are connected to INT_GROUP0, and INT_GROUP0 sources NVIC peripheral interrupt 0. If the WWDT0 interrupt is asserted, INT_GROUP0 will assert an interrupt request to the NVIC. If no higher priority interrupt is active, the NVIC will vector the processor to the INT_GROUP0 handler. Application software can then read the INT_GROUP0 IIDX register to determine that it was the WWDT0 that triggered the INT_GROUP0 interrupt on the NVIC, and software can jump to the WWDT0 handler function.

If the PMCU asserts its interrupt line while the processor is still in handler mode servicing the WWDT0 function (which is really a part of the INT_GROUP0 handler), the PMCU interrupt can not preempt the WWDT0 handler. When the WWDT0 handler completes, The INT_GROUP0 handler will return. At that time, the processor will see that the INT_GROUP0 request was asserted again (this time, due to the PMCU), and it will tail-chain a second entry to the interrupt handler. This time, application software will read the IIDX and determine that the PMCU was the cause of the INT_GROUP0 interrupt being asserted to the NVIC.

If there are two or more peripheral interrupts pending to a single interrupt group, software can set the priority with which the interrupts are handled by first reading the RIS or MIS register to test which peripheral interrupts are asserted, followed by executing the software-determined priority. Alternatively, if the interrupt index (IIDX) register is used, the interrupt group hardware will return the highest priority index based on the index order.