SLAU893B October   2023  – July 2024 MSPM0C1103 , MSPM0C1103-Q1 , MSPM0C1104 , MSPM0C1104-Q1

 

  1.   1
  2.   Read This First
    1.     About This Manual
    2.     Notational Conventions
    3.     Glossary
    4.     Related Documentation
    5.     Support Resources
    6.     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 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
    5. 1.5 NONMAIN_C1103_C1104 Registers
    6. 1.6 Factory Constants
      1. 1.6.1 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 Peripheral Power Enable Control
        1. 2.2.6.1 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 Frequency Correction Loop
            1. 2.3.1.2.1.1 SYSOSC FCL in Internal Resistor Mode
          2. 2.3.1.2.2 Disabling SYSOSC
        3. 2.3.1.3 LFCLK_IN (Digital Clock)
        4. 2.3.1.4 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 LFCLK (Low-Frequency Clock)
        6. 2.3.2.6 ADCCLK (ADC Sample Period Clock)
        7. 2.3.2.7 External Clock Output (CLK_OUT)
        8. 2.3.2.8 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 MCLK Monitor
        2. 2.3.4.2 Startup Monitors
          1. 2.3.4.2.1 LFOSC Startup Monitor
      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  Shutdown Mode Handling
      7. 2.4.7  Configuration Lockout
      8. 2.4.8  System Status
      9. 2.4.9  Error Handling
      10. 2.4.10 SYSCTL Events
        1. 2.4.10.1 CPU Interrupt Event (CPU_INT)
    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 Optimizing for Lowest Wakeup Latency
      6. 2.5.6 Optimizing for Lowest Peak Current in RUN/SLEEP Mode
    6. 2.6 SYSCTL_C1103_C1104 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)
    5. 3.5 Read-Only Memory (ROM)
    6. 3.6 CPUSS Registers
    7. 3.7 WUC Registers
  6. 4 DMA
    1. 4.1 DMA Overview
    2. 4.2 DMA Operation
      1. 4.2.1  Addressing Modes
      2. 4.2.2  Channel Types
      3. 4.2.3  Transfer Modes
        1. 4.2.3.1 Single Transfer
        2. 4.2.3.2 Block Transfer
        3. 4.2.3.3 Repeated Single Transfer
        4. 4.2.3.4 Repeated Block Transfer
        5. 4.2.3.5 Stride Mode
      4. 4.2.4  Extended Modes
        1. 4.2.4.1 Fill Mode
        2. 4.2.4.2 Table Mode
      5. 4.2.5  Initiating DMA Transfers
      6. 4.2.6  Stopping DMA Transfers
      7. 4.2.7  Channel Priorities
      8. 4.2.8  Burst Block Mode
      9. 4.2.9  Using DMA with System Interrupts
      10. 4.2.10 DMA Controller Interrupts
      11. 4.2.11 DMA Trigger Event Status
      12. 4.2.12 DMA Operating Mode Support
        1. 4.2.12.1 Transfer in RUN Mode
        2. 4.2.12.2 Transfer in SLEEP Mode
        3. 4.2.12.3 Transfer in STOP Mode
        4. 4.2.12.4 Transfers in STANDBY Mode
      13. 4.2.13 DMA Address and Data Errors
      14. 4.2.14 Interrupt and Event Support
    3. 4.3 DMA Registers
  7. 5 NVM (Flash)
    1. 5.1 NVM Overview
      1. 5.1.1 Key Features
      2. 5.1.2 System Components
      3. 5.1.3 Terminology
    2. 5.2 Flash Memory Bank Organization
      1. 5.2.1 Banks
      2. 5.2.2 Flash Memory Regions
      3. 5.2.3 Addressing
        1. 5.2.3.1 Flash Memory Map
      4. 5.2.4 Memory Organization Examples
    3. 5.3 Flash Controller
      1. 5.3.1 Overview of Flash Controller Commands
      2. 5.3.2 NOOP Command
      3. 5.3.3 PROGRAM Command
        1. 5.3.3.1 Program Bit Masking Behavior
        2. 5.3.3.2 Programming Less Than One Flash Word
        3. 5.3.3.3 Target Data Alignment (Devices with Single Flash Word Programming Only)
        4. 5.3.3.4 Target Data Alignment (Devices With Multiword Programming)
        5. 5.3.3.5 Executing a PROGRAM Operation
      4. 5.3.4 ERASE Command
        1. 5.3.4.1 Erase Sector Masking Behavior
        2. 5.3.4.2 Executing an ERASE Operation
      5. 5.3.5 READVERIFY Command
        1. 5.3.5.1 Executing a READVERIFY Operation
      6. 5.3.6 BLANKVERIFY Command
        1. 5.3.6.1 Executing a BLANKVERIFY Operation
      7. 5.3.7 Command Diagnostics
        1. 5.3.7.1 Command Status
        2. 5.3.7.2 Address Translation
        3. 5.3.7.3 Pulse Counts
      8. 5.3.8 Overriding the System Address With a Bank ID, Region ID, and Bank Address
      9. 5.3.9 FLASHCTL Events
        1. 5.3.9.1 CPU Interrupt Event Publisher
    4. 5.4 Write Protection
      1. 5.4.1 Write Protection Resolution
      2. 5.4.2 Static Write Protection
      3. 5.4.3 Dynamic Write Protection
        1. 5.4.3.1 Configuring Protection for the MAIN Region
        2. 5.4.3.2 Configuring Protection for the NONMAIN Region
    5. 5.5 Read Interface
      1. 5.5.1 Bank Address Swapping
    6. 5.6 FLASHCTL Registers
  8. 6 Events
    1. 6.1 Events Overview
      1. 6.1.1 Event Publisher
      2. 6.1.2 Event Subscriber
      3. 6.1.3 Event Fabric Routing
        1. 6.1.3.1 CPU Interrupt Event Route (CPU_INT)
        2. 6.1.3.2 DMA Trigger Event Route (DMA_TRIGx)
        3. 6.1.3.3 Generic Event Route (GEN_EVENTx)
      4. 6.1.4 Event Routing Map
      5. 6.1.5 Event Propagation Latency
    2. 6.2 Events Operation
      1. 6.2.1 CPU Interrupt
      2. 6.2.2 DMA Trigger
      3. 6.2.3 Peripheral to Peripheral Event
      4. 6.2.4 Extended Module Description Register
      5. 6.2.5 Using Event Registers
        1. 6.2.5.1 Event Registers
        2. 6.2.5.2 Configuring Events
        3. 6.2.5.3 Responding to CPU Interrupts in Application Software
        4. 6.2.5.4 Hardware Event Handling
  9. 7 IOMUX
    1. 7.1 IOMUX Overview
      1. 7.1.1 IO Types and Analog Sharing
    2. 7.2 IOMUX Operation
      1. 7.2.1 Peripheral Function (PF) Assignment
      2. 7.2.2 Logic High to Hi-Z Conversion
      3. 7.2.3 Logic Inversion
      4. 7.2.4 SHUTDOWN Mode Wakeup Logic
      5. 7.2.5 Pullup/Pulldown Resistors
      6. 7.2.6 Drive Strength Control
      7. 7.2.7 Hysteresis and Logic Level Control
    3. 7.3 IOMUX (PINCMx) Register Format
    4. 7.4 IOMUX Registers
  10. 8 GPIO
    1. 8.1 GPIO Overview
    2. 8.2 GPIO Operation
      1. 8.2.1 GPIO Ports
      2. 8.2.2 GPIO Read/Write Interface
      3. 8.2.3 GPIO Input Glitch Filtering and Synchronization
      4. 8.2.4 GPIO Fast Wake
      5. 8.2.5 GPIO DMA Interface
      6. 8.2.6 Event Publishers and Subscribers
    3. 8.3 GPIO Registers
  11. 9 ADC
    1. 9.1 ADC Overview
    2. 9.2 ADC Operation
      1. 9.2.1  ADC Core
      2. 9.2.2  Voltage Reference Options
      3. 9.2.3  Generic Resolution Modes
      4. 9.2.4  Hardware Averaging
      5. 9.2.5  ADC Clocking
      6. 9.2.6  Common ADC Use Cases
      7. 9.2.7  Power Down Behavior
      8. 9.2.8  Sampling Trigger Sources and Sampling Modes
        1. 9.2.8.1 AUTO Sampling Mode
        2. 9.2.8.2 MANUAL Sampling Mode
      9. 9.2.9  Sampling Period
      10. 9.2.10 Conversion Modes
      11. 9.2.11 Data Format
      12. 9.2.12 Advanced Features
        1. 9.2.12.1 Window Comparator
        2. 9.2.12.2 DMA and FIFO Operation
        3. 9.2.12.3 Analog Peripheral Interconnection
      13. 9.2.13 Status Register
      14. 9.2.14 ADC Events
        1. 9.2.14.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 9.2.14.2 Generic Event Publisher (GEN_EVENT)
        3. 9.2.14.3 DMA Trigger Event Publisher (DMA_TRIG)
        4. 9.2.14.4 Generic Event Subscriber (FSUB_0)
    3. 9.3 ADC0 Registers
  12. 10VREF
    1. 10.1 VREF Overview
    2. 10.2 VREF Operation
      1. 10.2.1 Internal Reference Generation
    3. 10.3 VREF Registers
  13. 11UART
    1. 11.1 UART Overview
      1. 11.1.1 Purpose of the Peripheral
      2. 11.1.2 Features
      3. 11.1.3 Functional Block Diagram
    2. 11.2 UART Operation
      1. 11.2.1 Clock Control
      2. 11.2.2 Signal Descriptions
      3. 11.2.3 General Architecture and Protocol
        1. 11.2.3.1  Transmit Receive Logic
        2. 11.2.3.2  Bit Sampling
        3. 11.2.3.3  Majority Voting Feature
        4. 11.2.3.4  Baud Rate Generation
        5. 11.2.3.5  Data Transmission
        6. 11.2.3.6  Error and Status
        7. 11.2.3.7  Local Interconnect Network (LIN) Support
          1. 11.2.3.7.1 LIN Responder Transmission Delay
        8. 11.2.3.8  Flow Control
        9. 11.2.3.9  Idle-Line Multiprocessor
        10. 11.2.3.10 9-Bit UART Mode
        11. 11.2.3.11 RS485 Support
        12. 11.2.3.12 DALI Protocol
        13. 11.2.3.13 Manchester Encoding and Decoding
        14. 11.2.3.14 IrDA Encoding and Decoding
        15. 11.2.3.15 ISO7816 Smart Card Support
        16. 11.2.3.16 Address Detection
        17. 11.2.3.17 FIFO Operation
        18. 11.2.3.18 Loopback Operation
        19. 11.2.3.19 Glitch Suppression
      4. 11.2.4 Low Power Operation
      5. 11.2.5 Reset Considerations
      6. 11.2.6 Initialization
      7. 11.2.7 Interrupt and Events Support
        1. 11.2.7.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 11.2.7.2 DMA Trigger Publisher (DMA_TRIG_RX, DMA_TRIG_TX)
      8. 11.2.8 Emulation Modes
    3. 11.3 UART0 Registers
  14. 12SPI
    1. 12.1 SPI Overview
      1. 12.1.1 Purpose of the Peripheral
      2. 12.1.2 Features
      3. 12.1.3 Functional Block Diagram
      4. 12.1.4 External Connections and Signal Descriptions
    2. 12.2 SPI Operation
      1. 12.2.1 Clock Control
      2. 12.2.2 General Architecture
        1. 12.2.2.1 Chip Select and Command Handling
          1. 12.2.2.1.1 Chip Select Control
          2. 12.2.2.1.2 Command Data Control
        2. 12.2.2.2 Data Format
        3. 12.2.2.3 Delayed data sampling
        4. 12.2.2.4 Clock Generation
        5. 12.2.2.5 FIFO Operation
        6. 12.2.2.6 Loopback mode
        7. 12.2.2.7 DMA Operation
        8. 12.2.2.8 Repeat Transfer mode
        9. 12.2.2.9 Low Power Mode
      3. 12.2.3 Protocol Descriptions
        1. 12.2.3.1 Motorola SPI Frame Format
        2. 12.2.3.2 Texas Instruments Synchronous Serial Frame Format
      4. 12.2.4 Reset Considerations
      5. 12.2.5 Initialization
      6. 12.2.6 Interrupt and Events Support
        1. 12.2.6.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 12.2.6.2 DMA Trigger Publisher (DMA_TRIG_RX, DMA_TRIG_TX)
      7. 12.2.7 Emulation Modes
    3. 12.3 SPI Registers
  15. 13I2C
    1. 13.1 I2C Overview
      1. 13.1.1 Purpose of the Peripheral
      2. 13.1.2 Features
      3. 13.1.3 Functional Block Diagram
      4. 13.1.4 Environment and External Connections
    2. 13.2 I2C Operation
      1. 13.2.1 Clock Control
        1. 13.2.1.1 Clock Select and I2C Speed
        2. 13.2.1.2 Clock Startup
      2. 13.2.2 Signal Descriptions
      3. 13.2.3 General Architecture
        1. 13.2.3.1  I2C Bus Functional Overview
        2. 13.2.3.2  START and STOP Conditions
        3. 13.2.3.3  Data Format with 7-Bit Address
        4. 13.2.3.4  Acknowledge
        5. 13.2.3.5  Repeated Start
        6. 13.2.3.6  SCL Clock Low Timeout
        7. 13.2.3.7  Clock Stretching
        8. 13.2.3.8  Dual Address
        9. 13.2.3.9  Arbitration
        10. 13.2.3.10 Multiple Controller Mode
        11. 13.2.3.11 Glitch Suppression
        12. 13.2.3.12 FIFO operation
          1. 13.2.3.12.1 Flushing Stale Tx Data in Target Mode
        13. 13.2.3.13 Loopback mode
        14. 13.2.3.14 Burst Mode
        15. 13.2.3.15 DMA Operation
        16. 13.2.3.16 Low-Power Operation
      4. 13.2.4 Protocol Descriptions
        1. 13.2.4.1 I2C Controller Mode
          1. 13.2.4.1.1 Controller Configuration
          2. 13.2.4.1.2 Controller Mode Operation
          3. 13.2.4.1.3 Read On TX Empty
        2. 13.2.4.2 I2C Target Mode
          1. 13.2.4.2.1 Target Mode Operation
      5. 13.2.5 Reset Considerations
      6. 13.2.6 Initialization
      7. 13.2.7 Interrupt and Events Support
        1. 13.2.7.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 13.2.7.2 DMA Trigger Publisher (DMA_TRIG1, DMA_TRIG0)
      8. 13.2.8 Emulation Modes
    3. 13.3 I2C Registers
  16. 14CRC
    1. 14.1 CRC Overview
      1. 14.1.1 CRC16-CCITT
    2. 14.2 CRC Operation
      1. 14.2.1 CRC Generator Implementation
      2. 14.2.2 Configuration
        1. 14.2.2.1 Bit Order
        2. 14.2.2.2 Byte Swap
        3. 14.2.2.3 Byte Order
        4. 14.2.2.4 CRC C Library Compatibility
    3. 14.3 CRC Registers
  17. 15Timers (TIMx)
    1. 15.1 TIMx Overview
      1. 15.1.1 TIMG Overview
        1. 15.1.1.1 TIMG Features
        2. 15.1.1.2 Functional Block Diagram
      2. 15.1.2 TIMA Overview
        1. 15.1.2.1 TIMA Features
        2. 15.1.2.2 Functional Block Diagram
      3. 15.1.3 TIMx Instance Configuration
    2. 15.2 TIMx Operation
      1. 15.2.1  Timer Counter
        1. 15.2.1.1 Clock Source Select and Prescaler
          1. 15.2.1.1.1 Internal Clock and Prescaler
          2. 15.2.1.1.2 External Signal Trigger
        2. 15.2.1.2 Repeat Counter (TIMA only)
      2. 15.2.2  Counting Mode Control
        1. 15.2.2.1 One-shot and Periodic Modes
        2. 15.2.2.2 Down Counting Mode
        3. 15.2.2.3 Up/Down Counting Mode
        4. 15.2.2.4 Up Counting Mode
        5. 15.2.2.5 Phase Load (TIMA only)
      3. 15.2.3  Capture/Compare Module
        1. 15.2.3.1 Capture Mode
          1. 15.2.3.1.1 Input Selection, Counter Conditions, and Inversion
            1. 15.2.3.1.1.1 CCP Input Edge Synchronization
            2. 15.2.3.1.1.2 CCP Input Pulse Conditions
            3. 15.2.3.1.1.3 Counter Control Operation
            4. 15.2.3.1.1.4 CCP Input Filtering
            5. 15.2.3.1.1.5 Input Selection
          2. 15.2.3.1.2 Use Cases
            1. 15.2.3.1.2.1 Edge Time Capture
            2. 15.2.3.1.2.2 Period Capture
            3. 15.2.3.1.2.3 Pulse Width Capture
            4. 15.2.3.1.2.4 Combined Pulse Width and Period Time
          3. 15.2.3.1.3 QEI Mode (TIMG with QEI support only)
            1. 15.2.3.1.3.1 QEI With 2-Signal
            2. 15.2.3.1.3.2 QEI With Index Input
            3. 15.2.3.1.3.3 QEI Error Detection
          4. 15.2.3.1.4 Hall Input Mode (TIMG with QEI support only)
        2. 15.2.3.2 Compare Mode
          1. 15.2.3.2.1 Edge Count
      4. 15.2.4  Shadow Load and Shadow Compare
        1. 15.2.4.1 Shadow Load (TIMG4-7, TIMA only)
        2. 15.2.4.2 Shadow Compare (TIMG4-7, TIMG12-13, TIMA only)
      5. 15.2.5  Output Generator
        1. 15.2.5.1 Configuration
        2. 15.2.5.2 Use Cases
          1. 15.2.5.2.1 Edge-Aligned PWM
          2. 15.2.5.2.2 Center-Aligned PWM
          3. 15.2.5.2.3 Asymmetric PWM (TIMA only)
          4. 15.2.5.2.4 Complementary PWM With Deadband Insertion (TIMA only)
        3. 15.2.5.3 Forced Output
      6. 15.2.6  Fault Handler (TIMA only)
        1. 15.2.6.1 Fault Input Conditioning
        2. 15.2.6.2 Fault Input Sources
        3. 15.2.6.3 Counter Behavior With Fault Conditions
        4. 15.2.6.4 Output Behavior With Fault Conditions
      7. 15.2.7  Synchronization With Cross Trigger
        1. 15.2.7.1 Main Timer Cross Trigger Configuration
        2. 15.2.7.2 Secondary Timer Cross Trigger Configuration
      8. 15.2.8  Low Power Operation
      9. 15.2.9  Interrupt and Event Support
        1. 15.2.9.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 15.2.9.2 Generic Event Publisher and Subscriber (GEN_EVENT0 and GEN_EVENT1)
        3. 15.2.9.3 Generic Subscriber Event Example (COMP to TIMx)
      10. 15.2.10 Debug Handler (TIMA Only)
    3. 15.3 TIMx Registers
  18. 16WWDT
    1. 16.1 WWDT Overview
      1. 16.1.1 Watchdog Mode
      2. 16.1.2 Interval Timer Mode
    2. 16.2 WWDT Operation
      1. 16.2.1 Mode Selection
      2. 16.2.2 Clock Configuration
      3. 16.2.3 Low-Power Mode Behavior
      4. 16.2.4 Debug Behavior
      5. 16.2.5 WWDT Events
        1. 16.2.5.1 CPU Interrupt Event Publisher (CPU_INT)
    3. 16.3 WWDT Registers
  19. 17Debug
    1. 17.1 Overview
      1. 17.1.1 Debug Interconnect
      2. 17.1.2 Physical Interface
      3. 17.1.3 Debug Access Ports
    2. 17.2 Debug Features
      1. 17.2.1 Processor Debug
        1. 17.2.1.1 Breakpoint Unit (BPU)
        2. 17.2.1.2 Data Watchpoint and Trace Unit (DWT)
      2. 17.2.2 Peripheral Debug
      3. 17.2.3 EnergyTrace Technology
    3. 17.3 Behavior in Low Power Modes
    4. 17.4 Restricting Debug Access
    5. 17.5 Mailbox (DSSM)
      1. 17.5.1 DSSM Events
        1. 17.5.1.1 CPU Interrupt Event (CPU_INT)
      2. 17.5.2 DEBUGSS Registers
  20. 18Revision History

2.5.2 Leveraging MFCLK

When running with the default PMCU configuration, timers and serial interfaces can select either the bus clock (MCLK/ULPCLK) or the LFCLK as their clock source. LFCLK is always 32kHz in RUN, SLEEP, STOP, and STANDBY, but MCLK/ULPCLK changes to 4MHz in STOP and to 32kHz in STANDBY, meaning that peripherals running from the bus clock see the source clock frequency change when transitioning power modes.

MFCLK, by contrast, works like LFCLK in that it provides a constant frequency clock source for peripherals across RUN, SLEEP, and STOP modes. MFCLK provides a constant 4MHz as an alternative to LFCLK which runs at 32kHz. The 4MHz time base for MFCLK is always derived from SYSOSC. Peripherals, specifically PD0 peripherals that can be used in STOP mode, can select MFCLK as their clock source instead of ULPCLK. MFCLK is maintained at 4MHz in RUN, SLEEP and STOP for peripherals like UART, I2C, and low-power timers that need a consistent clock but require a clock source greater than 32kHz.

For information on using MFCLK, see the MFCLK section.