SLAU847F October   2022  â€“ March 2026 MSPM0L1105 , MSPM0L1106 , MSPM0L1116 , MSPM0L1117 , MSPM0L1227 , MSPM0L1227-Q1 , MSPM0L1228 , MSPM0L1228-Q1 , MSPM0L1303 , MSPM0L1304 , MSPM0L1304-Q1 , MSPM0L1305 , MSPM0L1305-Q1 , MSPM0L1306 , MSPM0L1306-Q1 , MSPM0L1343 , MSPM0L1344 , MSPM0L1345 , MSPM0L1346 , MSPM0L2116 , MSPM0L2117 , MSPM0L2227 , MSPM0L2227-Q1 , MSPM0L2228 , MSPM0L2228-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 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
      4. 1.4.4 NONMAIN Layout Types
      5. 1.4.5 NONMAIN_TYPEA Registers
      6. 1.4.6 NONMAIN_TYPEC Registers
      7. 1.4.7 NONMAIN_TYPEE Registers
    5. 1.5 Factory Constants
      1. 1.5.1 FACTORYREGION Layout Types
      2. 1.5.2 FACTORYREGION_TYPEA Registers
      3. 1.5.3 FACTORYREGION_TYPEC Registers
      4. 1.5.4 FACTORYREGION_TYPED Registers
      5. 1.5.5 FACTORYREGION_TYPEE 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)
        2. 2.2.3.2 Brownout Reset (BOR)
        3. 2.2.3.3 POR and BOR Behavior During Supply Changes
      4. 2.2.4 Bandgap Reference
      5. 2.2.5 VBOOST for Analog Muxes
      6. 2.2.6 Peripheral Enable
        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 Gear Shift
          2. 2.3.1.2.2 SYSOSC Frequency
          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 Low Frequency Crystal Oscillator (LFXT)
        4. 2.3.1.4 LFCLK_IN (Digital Clock)
        5. 2.3.1.5 High Frequency Crystal Oscillator (HFXT)
        6. 2.3.1.6 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 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 Power-Up
        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 SYSCTL Layout Types
    6. 2.6 SYSCTL_TYPEA Registers
    7. 2.7 SYSCTL_TYPEB Registers
    8. 2.8 SYSCTL_TYPEC Registers
    9. 2.9 Quick Start Reference
      1. 2.9.1 Default Device Configuration
      2. 2.9.2 Leveraging MFCLK
      3. 2.9.3 Optimizing Power Consumption in STOP Mode
      4. 2.9.4 Optimizing Power Consumption in STANDBY Mode
      5. 2.9.5 Increasing MCLK Precision
      6. 2.9.6 High Speed Clock (SYSPLL, HFCLK) Handling in Low-Power Modes
      7. 2.9.7 Optimizing for Lowest Wakeup Latency
      8. 2.9.8 Optimizing for Lowest Peak Current in RUN/SLEEP Mode
  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)
    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 Direct Memory Access (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 NVM (Flash)
    1. 6.1 NVM Overview
      1. 6.1.1 Key Features
      2. 6.1.2 System Components
      3. 6.1.3 Terminology
    2. 6.2 Flash Memory Bank Organization
      1. 6.2.1 Banks
      2. 6.2.2 Flash Memory Regions
      3. 6.2.3 Addressing
        1. 6.2.3.1 Flash Memory Map
      4. 6.2.4 Memory Organization Examples
    3. 6.3 Flash Controller
      1. 6.3.1 Overview of Flash Controller Commands
      2. 6.3.2 NOOP Command
      3. 6.3.3 PROGRAM Command
        1. 6.3.3.1 Program Bit Masking Behavior
        2. 6.3.3.2 Programming Less Than One Flash Word
        3. 6.3.3.3 Target Data Alignment (Devices with Single Flash Word Programming Only)
        4. 6.3.3.4 Target Data Alignment (Devices With Multiword Programming)
        5. 6.3.3.5 Executing a PROGRAM Operation
      4. 6.3.4 ERASE Command
        1. 6.3.4.1 Erase Sector Masking Behavior
        2. 6.3.4.2 Executing an ERASE Operation
      5. 6.3.5 READVERIFY Command
        1. 6.3.5.1 Executing a READVERIFY Operation
      6. 6.3.6 BLANKVERIFY Command
        1. 6.3.6.1 Executing a BLANKVERIFY Operation
      7. 6.3.7 Command Diagnostics
        1. 6.3.7.1 Command Status
        2. 6.3.7.2 Address Translation
        3. 6.3.7.3 Pulse Counts
      8. 6.3.8 Overriding the System Address With a Bank ID, Region ID, and Bank Address
      9. 6.3.9 FLASHCTL Events
        1. 6.3.9.1 CPU Interrupt Event Publisher
    4. 6.4 Write Protection
      1. 6.4.1 Write Protection Resolution
      2. 6.4.2 Static Write Protection
      3. 6.4.3 Dynamic Write Protection
        1. 6.4.3.1 Configuring Protection for the MAIN Region
        2. 6.4.3.2 Configuring Protection for the NONMAIN Region
    5. 6.5 Read Interface
      1. 6.5.1 Bank Address Swapping
    6. 6.6 FLASHCTL Registers
  9. 7 Events
    1. 7.1 Events Overview
      1. 7.1.1 Event Publisher
      2. 7.1.2 Event Subscriber
      3. 7.1.3 Event Fabric Routing
        1. 7.1.3.1 CPU Interrupt Event Route (CPU_INT)
        2. 7.1.3.2 DMA Trigger Event Route (DMA_TRIGx)
        3. 7.1.3.3 Generic Event Route (GEN_EVENTx)
      4. 7.1.4 Event Routing Map
      5. 7.1.5 Event Propagation Latency
    2. 7.2 Events Operation
      1. 7.2.1 CPU Interrupt
      2. 7.2.2 DMA Trigger
      3. 7.2.3 Peripheral to Peripheral Event
      4. 7.2.4 Extended Module Description Register
      5. 7.2.5 Using Event Registers
        1. 7.2.5.1 Event Registers
        2. 7.2.5.2 Configuring Events
        3. 7.2.5.3 Responding to CPU Interrupts in Application Software
        4. 7.2.5.4 Hardware Event Handling
  10. 8 IOMUX
    1. 8.1 IOMUX Overview
      1. 8.1.1 IO Types and Analog Sharing
    2. 8.2 IOMUX Operation
      1. 8.2.1 Peripheral Function (PF) Assignment
      2. 8.2.2 Logic High to Hi-Z Conversion
      3. 8.2.3 Logic Inversion
      4. 8.2.4 SHUTDOWN Mode Wakeup Logic
      5. 8.2.5 Pullup/Pulldown Resistors
      6. 8.2.6 Drive Strength Control
      7. 8.2.7 Hysteresis and Logic Level Control
    3. 8.3 IOMUX Registers
  11. 9 General-Purpose Input/Output (GPIO)
    1. 9.1 GPIO Overview
    2. 9.2 GPIO Operation
      1. 9.2.1 GPIO Ports
      2. 9.2.2 GPIO Read/Write Interface
      3. 9.2.3 GPIO Input Glitch Filtering and Synchronization
      4. 9.2.4 GPIO Fast Wake
      5. 9.2.5 GPIO DMA Interface
      6. 9.2.6 Event Publishers and Subscribers
    3. 9.3 GPIO Registers
  12. 10AES
    1. 10.1 AES Overview
      1. 10.1.1 AESADV Performance
    2. 10.2 AESADV Operation
      1. 10.2.1 Loading the Key
      2. 10.2.2 Writing Input Data
      3. 10.2.3 Reading Output Data
      4. 10.2.4 Operation Descriptions
        1. 10.2.4.1 Single Block Operation
        2. 10.2.4.2 Electronic Codebook (ECB) Mode
          1. 10.2.4.2.1 ECB Encryption
          2. 10.2.4.2.2 ECB Decryption
        3. 10.2.4.3 Cipher Block Chaining (CBC) Mode
          1. 10.2.4.3.1 CBC Encryption
          2. 10.2.4.3.2 CBC Decryption
        4. 10.2.4.4 Output Feedback (OFB) Mode
          1. 10.2.4.4.1 OFB Encryption
          2. 10.2.4.4.2 OFB Decryption
        5. 10.2.4.5 Cipher Feedback (CFB) Mode
          1. 10.2.4.5.1 CFB Encryption
          2. 10.2.4.5.2 CFB Decryption
        6. 10.2.4.6 Counter (CTR) Mode
          1. 10.2.4.6.1 CTR Encryption
          2. 10.2.4.6.2 CTR Decryption
        7. 10.2.4.7 Galois Counter (GCM) Mode
          1. 10.2.4.7.1 GHASH Operation
          2. 10.2.4.7.2 GCM Operating Modes
            1. 10.2.4.7.2.1 Autonomous GCM Operation
              1. 10.2.4.7.2.1.1 GMAC
            2. 10.2.4.7.2.2 GCM With Pre-Calculations
            3. 10.2.4.7.2.3 GCM Operation With Precalculated H- and Y0-Encrypted Forced to Zero
        8. 10.2.4.8 Counter With Cipher Block Chaining Message Authentication Code (CCM)
          1. 10.2.4.8.1 CCM Operation
      5. 10.2.5 AES Events
        1. 10.2.5.1 CPU Interrupt Event Publisher (CPU_EVENT)
        2. 10.2.5.2 DMA Trigger Event Publisher (DMA_TRIG_DATAIN)
        3. 10.2.5.3 DMA Trigger Event Publisher (DMA_TRIG_DATAOUT)
    3. 10.3 AESADV Registers
  13. 11CRC
    1. 11.1 CRC Overview
      1. 11.1.1 CRC16-CCITT
      2. 11.1.2 CRC32-ISO3309
    2. 11.2 CRC Operation
      1. 11.2.1 CRC Generator Implementation
      2. 11.2.2 Configuration
        1. 11.2.2.1 Polynomial Selection
        2. 11.2.2.2 Bit Order
        3. 11.2.2.3 Byte Swap
        4. 11.2.2.4 Byte Order
        5. 11.2.2.5 CRC C Library Compatibility
    3. 11.3 CRCP0 Registers
  14. 12Keystore
    1. 12.1 Overview
    2. 12.2 Detailed Description
    3. 12.3 KEYSTORECTL Registers
  15. 13TRNG
    1. 13.1 TRNG Overview
    2. 13.2 TRNG Operation
      1. 13.2.1 TRNG Generation Data Path
      2. 13.2.2 Clock Configuration and Output Rate
      3. 13.2.3 Behavior in Low Power Modes
      4. 13.2.4 Health Tests
        1. 13.2.4.1 Digital Block Startup Self-Test
        2. 13.2.4.2 Analog Block Startup Self-Test
        3. 13.2.4.3 Runtime Health Test
          1. 13.2.4.3.1 Repetition Count Test
          2. 13.2.4.3.2 Adaptive Proportion Test
          3. 13.2.4.3.3 Handling Runtime Health Test Failures
      5. 13.2.5 Configuration
        1. 13.2.5.1 TRNG State Machine
          1. 13.2.5.1.1 Changing TRNG States
        2. 13.2.5.2 Using the TRNG
        3. 13.2.5.3 TRNG Events
          1. 13.2.5.3.1 CPU Interrupt Event Publisher (CPU_INT)
    3. 13.3 TRNG Registers
  16. 14Temperature Sensor
  17. 15ADC
    1. 15.1 ADC Overview
    2. 15.2 ADC Operation
      1. 15.2.1  ADC Core
      2. 15.2.2  Voltage Reference Options
      3. 15.2.3  Generic Resolution Modes
      4. 15.2.4  Hardware Averaging
      5. 15.2.5  ADC Clocking
      6. 15.2.6  Common ADC Use Cases
      7. 15.2.7  Power Down Behavior
      8. 15.2.8  Sampling Trigger Sources and Sampling Modes
        1. 15.2.8.1 AUTO Sampling Mode
        2. 15.2.8.2 MANUAL Sampling Mode
      9. 15.2.9  Sampling Period
      10. 15.2.10 Conversion Modes
      11. 15.2.11 Data Format
      12. 15.2.12 Advanced Features
        1. 15.2.12.1 Window Comparator
        2. 15.2.12.2 DMA and FIFO Operation
        3. 15.2.12.3 Analog Peripheral Interconnection
      13. 15.2.13 Status Register
      14. 15.2.14 ADC Events
        1. 15.2.14.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 15.2.14.2 Generic Event Publisher (GEN_EVENT)
        3. 15.2.14.3 DMA Trigger Event Publisher (DMA_TRIG)
        4. 15.2.14.4 Generic Event Subscriber (FSUB_0)
    3. 15.3 ADC12 Registers
  18. 16COMP
    1. 16.1 Comparator Overview
    2. 16.2 Comparator Operation
      1. 16.2.1  Comparator Configuration
      2. 16.2.2  Comparator Channels Selection
      3. 16.2.3  Comparator Output
      4. 16.2.4  Output Filter
      5. 16.2.5  Sampled Output Mode
      6. 16.2.6  Blanking Mode
      7. 16.2.7  Reference Voltage Generator
      8. 16.2.8  Comparator Hysteresis
      9. 16.2.9  Input SHORT Switch
      10. 16.2.10 Interrupt and Events Support
        1. 16.2.10.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 16.2.10.2 Generic Event Publisher (GEN_EVENT)
        3. 16.2.10.3 Generic Event Subscribers
    3. 16.3 COMP0 Registers
  19. 17OPA
    1. 17.1 OPA Overview
    2. 17.2 OPA Operation
      1. 17.2.1 Analog Core
      2. 17.2.2 Power Up Behavior
      3. 17.2.3 Inputs
      4. 17.2.4 Output
      5. 17.2.5 Clock Requirements
      6. 17.2.6 Chopping
      7. 17.2.7 OPA Amplifier Modes
        1. 17.2.7.1 General-Purpose Mode
        2. 17.2.7.2 Buffer Mode
        3. 17.2.7.3 OPA PGA Mode
          1. 17.2.7.3.1 Inverting PGA Mode
          2. 17.2.7.3.2 Non-inverting PGA Mode
        4. 17.2.7.4 Difference Amplifier Mode
        5. 17.2.7.5 Cascade Amplifier Mode
      8. 17.2.8 OPA Configuration Selection
      9. 17.2.9 Burnout Current Source
    3. 17.3 OA Registers
  20. 18GPAMP
    1. 18.1 GPAMP Overview
    2. 18.2 GPAMP Operation
      1. 18.2.1 Analog Core
      2. 18.2.2 Power Up Behavior
      3. 18.2.3 Inputs
      4. 18.2.4 Output
      5. 18.2.5 GPAMP Amplifier Modes
        1. 18.2.5.1 General-Purpose Mode
        2. 18.2.5.2 ADC Buffer Mode
        3. 18.2.5.3 Unity Gain Mode
      6. 18.2.6 Chopping
    3. 18.3 GPAMP Registers
  21. 19VREF
    1. 19.1 VREF Overview
    2. 19.2 VREF Operation
      1. 19.2.1 Internal Reference Generation
      2. 19.2.2 External Reference Input
      3. 19.2.3 Analog Peripheral Interface
    3. 19.3 VREF Registers
  22. 20LCD
    1. 20.1 LCD Introduction
      1. 20.1.1 LCD Operating Principle
      2. 20.1.2 Static Mode
      3. 20.1.3 2-Mux Mode
      4. 20.1.4 3-Mux Mode
      5. 20.1.5 4-Mux Mode
      6. 20.1.6 6-Mux Mode
      7. 20.1.7 8-Mux Mode
      8. 20.1.8 Introduction
      9. 20.1.9 LCD Waveforms
    2. 20.2 LCD Clocking
    3. 20.3 Voltage Generation
      1. 20.3.1  Mode 0 - Voltage Generation from external reference and external resistor divider
      2. 20.3.2  Mode 1 - Voltage Generation from AVDD and external resistor divider
      3. 20.3.3  Mode 2 - Voltage Generation from external reference and internal resistor divider
      4. 20.3.4  Mode 3 - Voltage Generation From AVDD and Internal Resistor Ladder
      5. 20.3.5  Mode 4 - Voltage Generation from charge pump with external supply
      6. 20.3.6  Mode 5 - Voltage Generation From Charge Pump With AVDD
      7. 20.3.7  Mode 6 - Voltage Generation From Charge Pump With External Reference on R13
      8. 20.3.8  Mode 7 - Voltage Generation From Charge Pump With Internal Reference on R13
      9. 20.3.9  Charge pump
      10. 20.3.10 Internal Reference Generation
    4. 20.4 Analog Mux
      1. 20.4.1 Static Mode
      2. 20.4.2 Non-Static 1/3 bias mode
      3. 20.4.3 Non-Static 1/4 bias mode
      4. 20.4.4 Low power mode switch controls
    5. 20.5 LCD Memory and output drive
      1. 20.5.1 LCD Memory organization
        1. 20.5.1.1 Memory Organization in Mux-1 to Mux-4 Modes
        2. 20.5.1.2 Memory Organization in Mux-5 to Mux-8 Modes
        3. 20.5.1.3 Configuring memory
        4. 20.5.1.4 Accessing memory and output drive
        5. 20.5.1.5 Blinking Override
    6. 20.6 IO Muxing
    7. 20.7 Interrupt Generation
    8. 20.8 Power Domains and Power Modes
    9. 20.9 LCD Registers
  23. 21UART
    1. 21.1 UART Overview
      1. 21.1.1 Purpose of the Peripheral
      2. 21.1.2 Features
      3. 21.1.3 Functional Block Diagram
    2. 21.2 UART Operation
      1. 21.2.1 Clock Control
      2. 21.2.2 Signal Descriptions
      3. 21.2.3 General Architecture and Protocol
        1. 21.2.3.1  Transmit Receive Logic
        2. 21.2.3.2  Bit Sampling
        3. 21.2.3.3  Majority Voting Feature
        4. 21.2.3.4  Baud Rate Generation
        5. 21.2.3.5  Data Transmission
        6. 21.2.3.6  Error and Status
        7. 21.2.3.7  Local Interconnect Network (LIN) Support
          1. 21.2.3.7.1 LIN Responder Transmission Delay
        8. 21.2.3.8  Flow Control
        9. 21.2.3.9  Idle-Line Multiprocessor
        10. 21.2.3.10 9-Bit UART Mode
        11. 21.2.3.11 RS-485 Support
        12. 21.2.3.12 DALI Protocol
        13. 21.2.3.13 Manchester Encoding and Decoding
        14. 21.2.3.14 IrDA Encoding and Decoding
        15. 21.2.3.15 ISO7816 Smart Card Support
        16. 21.2.3.16 Address Detection
        17. 21.2.3.17 FIFO Operation
        18. 21.2.3.18 Loopback Operation
        19. 21.2.3.19 Glitch Suppression
      4. 21.2.4 Low Power Operation
      5. 21.2.5 Reset Considerations
      6. 21.2.6 Initialization
      7. 21.2.7 Interrupt and Events Support
        1. 21.2.7.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 21.2.7.2 DMA Trigger Publisher (DMA_TRIG_RX, DMA_TRIG_TX)
      8. 21.2.8 Emulation Modes
    3. 21.3 UART Registers
  24. 22I2C
    1. 22.1 I2C Overview
      1. 22.1.1 Purpose of the Peripheral
      2. 22.1.2 Features
      3. 22.1.3 Functional Block Diagram
      4. 22.1.4 Environment and External Connections
    2. 22.2 I2C Operation
      1. 22.2.1 Clock Control
        1. 22.2.1.1 Clock Select and I2C Speed
        2. 22.2.1.2 Clock Startup
      2. 22.2.2 Signal Descriptions
      3. 22.2.3 General Architecture
        1. 22.2.3.1  I2C Bus Functional Overview
        2. 22.2.3.2  START and STOP Conditions
        3. 22.2.3.3  Data Format with 7-Bit Address
        4. 22.2.3.4  Acknowledge
        5. 22.2.3.5  Repeated Start
        6. 22.2.3.6  SCL Clock Low Timeout
        7. 22.2.3.7  Clock Stretching
        8. 22.2.3.8  Dual Address
        9. 22.2.3.9  Arbitration
        10. 22.2.3.10 Multiple Controller Mode
        11. 22.2.3.11 Glitch Suppression
        12. 22.2.3.12 FIFO operation
          1. 22.2.3.12.1 Flushing Stale Tx Data in Target Mode
        13. 22.2.3.13 Loopback mode
        14. 22.2.3.14 Burst Mode
        15. 22.2.3.15 DMA Operation
        16. 22.2.3.16 Low-Power Operation
      4. 22.2.4 Protocol Descriptions
        1. 22.2.4.1 I2C Controller Mode
          1. 22.2.4.1.1 Controller Configuration
          2. 22.2.4.1.2 Controller Mode Operation
          3. 22.2.4.1.3 Read On TX Empty
        2. 22.2.4.2 I2C Target Mode
          1. 22.2.4.2.1 Target Mode Operation
      5. 22.2.5 Reset Considerations
      6. 22.2.6 Initialization
      7. 22.2.7 Interrupt and Events Support
        1. 22.2.7.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 22.2.7.2 DMA Trigger Publisher (DMA_TRIG1, DMA_TRIG0)
      8. 22.2.8 Emulation Modes
    3. 22.3 I2C Registers
  25. 23SPI
    1. 23.1 SPI Overview
      1. 23.1.1 Purpose of the Peripheral
      2. 23.1.2 Features
      3. 23.1.3 Functional Block Diagram
      4. 23.1.4 External Connections and Signal Descriptions
    2. 23.2 SPI Operation
      1. 23.2.1 Clock Control
      2. 23.2.2 General Architecture
        1. 23.2.2.1 Chip Select and Command Handling
          1. 23.2.2.1.1 Chip Select Control
          2. 23.2.2.1.2 Command Data Control
        2. 23.2.2.2 Data Format
        3. 23.2.2.3 Delayed data sampling
        4. 23.2.2.4 Clock Generation
        5. 23.2.2.5 FIFO Operation
        6. 23.2.2.6 Loopback mode
        7. 23.2.2.7 DMA Operation
        8. 23.2.2.8 Repeat Transfer mode
        9. 23.2.2.9 Low Power Mode
      3. 23.2.3 Protocol Descriptions
        1. 23.2.3.1 Motorola SPI Frame Format
        2. 23.2.3.2 Texas Instruments Synchronous Serial Frame Format
      4. 23.2.4 Reset Considerations
      5. 23.2.5 Initialization
      6. 23.2.6 Interrupt and Events Support
        1. 23.2.6.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 23.2.6.2 DMA Trigger Publisher (DMA_TRIG_RX, DMA_TRIG_TX)
      7. 23.2.7 Emulation Modes
    3. 23.3 SPI Registers
  26. 24UNICOMM
    1. 24.1 Overview
      1. 24.1.1 Block Diagram
    2. 24.2 Unicomm Architecture
      1. 24.2.1 Serial Peripheral Group (SPG) Configurations
        1. 24.2.1.1 I2C Pairings
      2. 24.2.2 Enables & Resets
    3. 24.3 High-Level Initialization
    4. 24.4 UNICOMM/SPGSS Registers
      1. 24.4.1 UNICOMM Registers
        1. 24.4.1.1 UNICOMM Registers
      2. 24.4.2 SPG Registers
        1. 24.4.2.1 SPGSS Registers
  27. 25UNICOMM UART
    1. 25.1 UART Overview
      1. 25.1.1 Purpose of the Peripheral
      2. 25.1.2 Features
      3. 25.1.3 Functional Block Diagram
    2. 25.2 UART Operation
      1. 25.2.1 Clock Control
      2. 25.2.2 General Architecture and Protocol
        1. 25.2.2.1 Signal Descriptions
        2. 25.2.2.2 Transmit and Receive Logic
        3. 25.2.2.3 Bit Sampling
        4. 25.2.2.4 Baud Rate Generation
        5. 25.2.2.5 Data Transmission
        6. 25.2.2.6 Error and Status
        7. 25.2.2.7 DMA Operation
        8. 25.2.2.8 Internal Loopback Operation
      3. 25.2.3 Additional Protocol and Feature Support
        1. 25.2.3.1  Local Interconnect Network (LIN) Support
          1. 25.2.3.1.1 LIN Commander Transmit
          2. 25.2.3.1.2 LIN Responder Receive
          3. 25.2.3.1.3 LIN Responder Transmission Delay
        2. 25.2.3.2  Flow Control
        3. 25.2.3.3  RS485 Support
        4. 25.2.3.4  FIFO Operation
        5. 25.2.3.5  Idle-Line Multiprocessor
        6. 25.2.3.6  9-Bit UART Mode
        7. 25.2.3.7  DALI Protocol
        8. 25.2.3.8  Manchester Encoding and Decoding
        9. 25.2.3.9  IrDA Encoding and Decoding
        10. 25.2.3.10 ISO7816 Smart Card Support
        11. 25.2.3.11 Address Detection
        12. 25.2.3.12 Glitch Suppression
      4. 25.2.4 Low Power Operation
      5. 25.2.5 Reset Considerations
      6. 25.2.6 UART Initialization
      7. 25.2.7 Interrupt and Events Support
        1. 25.2.7.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 25.2.7.2 DMA Trigger Publisher (DMA_TRIG_RX, DMA_TRIG_TX)
      8. 25.2.8 Emulation Modes
    3. 25.3 UNICOMMUART Registers
  28. 26UNICOMM-I2C
    1. 26.1 UNICOMM-I2C Overview
      1. 26.1.1 Purpose of the Peripheral
      2. 26.1.2 Features
      3. 26.1.3 Functional Block Diagram
      4. 26.1.4 Environment and External Connections
    2. 26.2 UNICOMM Common Infrastructure
    3. 26.3 Peripheral Functional Description
      1. 26.3.1 Clock Control
        1. 26.3.1.1 Clock Select and I2C Speed
        2. 26.3.1.2 Clock Startup
      2. 26.3.2 Signal Descriptions
      3. 26.3.3 General Architecture
        1. 26.3.3.1  I2C Bus Functional Overview
        2. 26.3.3.2  START and STOP Conditions
        3. 26.3.3.3  Dual Address
        4. 26.3.3.4  Address Format
          1. 26.3.3.4.1 Data Format with 7-Bit Address
          2. 26.3.3.4.2 Data Format with 10-Bit Address
        5. 26.3.3.5  Acknowledge
        6. 26.3.3.6  Repeated Start
        7. 26.3.3.7  Clock Stretching
        8. 26.3.3.8  Clock Low Timeout
        9. 26.3.3.9  Burst Mode
        10. 26.3.3.10 Arbitration
        11. 26.3.3.11 Multiple Controller Mode
        12. 26.3.3.12 Glitch Suppression
        13. 26.3.3.13 DMA Operation
        14. 26.3.3.14 FIFO Operation
          1. 26.3.3.14.1 FIFO Status Flags
          2. 26.3.3.14.2 FIFO Levels
          3. 26.3.3.14.3 Clearing FIFO Contents
        15. 26.3.3.15 Suspend Communication
        16. 26.3.3.16 Low Power Operation
        17. 26.3.3.17 SMBUS 3.0 Support
          1. 26.3.3.17.1 Quick Command
          2. 26.3.3.17.2 SMBUS Enhanced Acknowledge Control
          3. 26.3.3.17.3 Clock Low Timeout Detection
          4. 26.3.3.17.4 Clock High Timeout Detection
          5. 26.3.3.17.5 Cumulative Clock Low Extended Timeout
          6. 26.3.3.17.6 Packet Error Checking (PEC)
          7. 26.3.3.17.7 Host Notify Protocol
          8. 26.3.3.17.8 Alert Response Protocol
          9. 26.3.3.17.9 Address Resolution Protocol
      4. 26.3.4 Protocol Descriptions & Initialization
        1. 26.3.4.1 I2C Controller Mode
          1. 26.3.4.1.1 I2C Controller Initialization
          2. 26.3.4.1.2 I2C Controller Status
          3. 26.3.4.1.3 I2C Controller Receive Mode
          4. 26.3.4.1.4 I2C Controller Transmitter Mode
          5. 26.3.4.1.5 Controller Transaction Configurations
        2. 26.3.4.2 I2C Target Mode
          1. 26.3.4.2.1 I2C Target Initialization
          2. 26.3.4.2.2 I2C Target Status
          3. 26.3.4.2.3 I2C Target Receiver Mode
          4. 26.3.4.2.4 I2C Target Transmitter Mode
      5. 26.3.5 Reset Considerations
      6. 26.3.6 Initialization
      7. 26.3.7 Interrupt and Events Support
        1. 26.3.7.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 26.3.7.2 DMA Trigger Publisher (DMA_TRIG_RX, DMA_TRIG_TX)
      8. 26.3.8 Emulation Modes
    4. 26.4 UNICOMM I2C Registers
      1. 26.4.1 UNICOMMI2CC Registers
      2. 26.4.2 UNICOMMI2CT Registers
  29. 27UNICOMM-SPI
    1. 27.1 UNICOMM-SPI Overview
      1. 27.1.1 Purpose of the Peripheral
      2. 27.1.2 Features
      3. 27.1.3 Functional Block Diagram
      4. 27.1.4 External Connections and Signal Descriptions
    2. 27.2 SPI Operation
      1. 27.2.1  Clock Frequency Support
        1. 27.2.1.1 SPI Clock Generation
      2. 27.2.2  General Architecture
        1. 27.2.2.1 Chip Select and Command Handling
          1. 27.2.2.1.1 Chip Select Control
        2. 27.2.2.2 Command Data Control
        3. 27.2.2.3 Data Format
        4. 27.2.2.4 Delayed data sampling
        5. 27.2.2.5 DMA Operation
      3. 27.2.3  FIFO Operation
        1. 27.2.3.1 FIFO Size
        2. 27.2.3.2 FIFO Status bits
          1. 27.2.3.2.1 RIS.RX based on FIFO threshold settings
          2. 27.2.3.2.2 RIS.TX based on FIFO threshold settings
        3. 27.2.3.3 Clearing FIFO contents
        4. 27.2.3.4 Hardware monitors empty, full and overflow conditions
      4. 27.2.4  Suspend communication
        1. 27.2.4.1 SPI IDLE State Requirements
      5. 27.2.5  Internal Loopback Operation
      6. 27.2.6  Repeat Transfer mode
      7. 27.2.7  Receive Timeout
      8. 27.2.8  Line Timeout
      9. 27.2.9  Protocol Descriptions
        1. 27.2.9.1 Motorola SPI Frame Format
        2. 27.2.9.2 Texas Instruments Synchronous Serial Frame Format
      10. 27.2.10 Status Flags
      11. 27.2.11 Module configuration
      12. 27.2.12 Reset Considerations
      13. 27.2.13 Initialization
      14. 27.2.14 Interrupt and Events Support
        1. 27.2.14.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 27.2.14.2 DMA Trigger Publisher (DMA_TRIG_RX, DMA_TRIG_TX)
      15. 27.2.15 Emulation Modes
        1. 27.2.15.1 Graceful Halt
    3. 27.3 UNICOMMSPI Registers
  30. 28Timers (TIMx)
    1. 28.1 TIMx Overview
      1. 28.1.1 TIMG Overview
        1. 28.1.1.1 TIMG Features
        2. 28.1.1.2 Functional Block Diagram
      2. 28.1.2 TIMA Overview
        1. 28.1.2.1 TIMA Features
        2. 28.1.2.2 Functional Block Diagram
      3. 28.1.3 TIMx Instance Configuration
    2. 28.2 TIMx Operation
      1. 28.2.1  Timer Counter
        1. 28.2.1.1 Clock Source Select and Prescaler
          1. 28.2.1.1.1 Internal Clock and Prescaler
          2. 28.2.1.1.2 External Signal Trigger
        2. 28.2.1.2 Repeat Counter (TIMA only)
      2. 28.2.2  Counting Mode Control
        1. 28.2.2.1 One-shot and Periodic Modes
        2. 28.2.2.2 Down Counting Mode
        3. 28.2.2.3 Up/Down Counting Mode
        4. 28.2.2.4 Up Counting Mode
        5. 28.2.2.5 Phase Load (TIMA only)
      3. 28.2.3  Capture/Compare Module
        1. 28.2.3.1 Capture Mode
          1. 28.2.3.1.1 Input Selection, Counter Conditions, and Inversion
            1. 28.2.3.1.1.1 CCP Input Edge Synchronization
            2. 28.2.3.1.1.2 CCP Input Pulse Conditions
            3. 28.2.3.1.1.3 Counter Control Operation
            4. 28.2.3.1.1.4 CCP Input Filtering
            5. 28.2.3.1.1.5 Input Selection
          2. 28.2.3.1.2 Use Cases
            1. 28.2.3.1.2.1 Edge Time Capture
            2. 28.2.3.1.2.2 Period Capture
            3. 28.2.3.1.2.3 Pulse Width Capture
            4. 28.2.3.1.2.4 Combined Pulse Width and Period Time
          3. 28.2.3.1.3 QEI Mode (TIMG with QEI support only)
            1. 28.2.3.1.3.1 QEI With 2-Signal
            2. 28.2.3.1.3.2 QEI With Index Input
            3. 28.2.3.1.3.3 QEI Error Detection
          4. 28.2.3.1.4 Hall Input Mode (TIMG with QEI support only)
        2. 28.2.3.2 Compare Mode
          1. 28.2.3.2.1 Edge Count
      4. 28.2.4  Shadow Load and Shadow Compare
        1. 28.2.4.1 Shadow Load (TIMG4-7, TIMA only)
        2. 28.2.4.2 Shadow Compare (TIMG4-7, TIMG12-13, TIMA only)
      5. 28.2.5  Output Generator
        1. 28.2.5.1 Configuration
        2. 28.2.5.2 Use Cases
          1. 28.2.5.2.1 Edge-Aligned PWM
          2. 28.2.5.2.2 Center-Aligned PWM
          3. 28.2.5.2.3 Asymmetric PWM (TIMA only)
          4. 28.2.5.2.4 Complementary PWM With Deadband Insertion (TIMA only)
        3. 28.2.5.3 Forced Output
      6. 28.2.6  Fault Handler (TIMA only)
        1. 28.2.6.1 Fault Input Conditioning
        2. 28.2.6.2 Fault Input Sources
        3. 28.2.6.3 Counter Behavior With Fault Conditions
        4. 28.2.6.4 Output Behavior With Fault Conditions
      7. 28.2.7  Synchronization With Cross Trigger
        1. 28.2.7.1 Main Timer Cross Trigger Configuration
        2. 28.2.7.2 Secondary Timer Cross Trigger Configuration
      8. 28.2.8  Low Power Operation
      9. 28.2.9  Interrupt and Event Support
        1. 28.2.9.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 28.2.9.2 Generic Event Publisher and Subscriber (GEN_EVENT0 and GEN_EVENT1)
        3. 28.2.9.3 Generic Subscriber Event Example (COMP to TIMx)
      10. 28.2.10 Debug Handler (TIMA Only)
    3. 28.3 TIMx Registers
  31. 29TIMB
    1. 29.1 TIMB Overview
      1. 29.1.1 Features
      2. 29.1.2 TIMB Block Diagram
    2. 29.2 TIMB Operation
      1. 29.2.1 Counter Block Operation
        1. 29.2.1.1 Clock Source Selection
        2. 29.2.1.2 Counter Reset Generation
        3. 29.2.1.3 Event Based Enable and Disable
        4. 29.2.1.4 Event Generation
        5. 29.2.1.5 Interrupt Generation
        6. 29.2.1.6 Counter Behavior on a Debug Halt
        7. 29.2.1.7 Hardware Locking of Configuration Registers
    3. 29.3 TIMB Example Applications
      1. 29.3.1 Periodic Interrupt Generation
      2. 29.3.2 Counter Chaining
      3. 29.3.3 Event Counting
      4. 29.3.4 Event Duration Measurement
      5. 29.3.5 Event Sequence Checking
      6. 29.3.6 PWM Generation
    4. 29.4 TIMB Registers
  32. 30Low Frequency Subsystem (LFSS)
    1. 30.1  Overview
    2. 30.2  Clock System
    3. 30.3  LFSS Reset Using VBAT
    4. 30.4  Power Domains and Supply Detection
      1. 30.4.1 Startup When VBAT Powers on First
      2. 30.4.2 Startup when VDD powers on first
      3. 30.4.3 Behavior When VDD is Lost
      4. 30.4.4 Behavior when VBAT is lost
      5. 30.4.5 Behavior when the device goes into SHUTDOWN mode
      6. 30.4.6 Supercapacitor Charging Circuit
    5. 30.5  Real Time Counter (RTC_x)
    6. 30.6  Independent Watchdog Timer (IWDT)
    7. 30.7  Tamper Input and Output
      1. 30.7.1 IOMUX Mode
      2. 30.7.2 Tamper Mode
        1. 30.7.2.1 Tamper Event Detection
        2. 30.7.2.2 Timestamp Event Output
        3. 30.7.2.3 Heartbeat Generator
        4. 30.7.2.4 RTC Clock Output
    8. 30.8  Scratchpad Memory
    9. 30.9  Lock Function of RTC, TIO, and IWDT
    10. 30.10 LFSS Registers
  33. 31Low Frequency Subsystem (LFSS_B)
    1. 31.1 Overview
    2. 31.2 Clock System
    3. 31.3 LFSS Reset
    4. 31.4 Real Time Counter (RTC_x)
    5. 31.5 Independent Watchdog Timer (IWDT)
    6. 31.6 Lock Function of RTC and IWDT
    7. 31.7 LFSS Registers
  34. 32RTC
    1. 32.1 Overview
      1. 32.1.1 RTC Instances
    2. 32.2 Basic Operation
    3. 32.3 Configuration
      1. 32.3.1  Clocking
      2. 32.3.2  Reading and Writing to RTC Peripheral Registers
      3. 32.3.3  Binary vs. BCD
      4. 32.3.4  Leap Year Handling
      5. 32.3.5  Calendar Alarm Configuration
      6. 32.3.6  Interval Alarm Configuration
      7. 32.3.7  Periodic Alarm Configuration
      8. 32.3.8  Calibration
        1. 32.3.8.1 Crystal Offset Error
          1. 32.3.8.1.1 Offset Error Correction Mechanism
        2. 32.3.8.2 Crystal Temperature Error
          1. 32.3.8.2.1 Temperature Drift Correction Mechanism
      9. 32.3.9  RTC Prescaler Extension
      10. 32.3.10 RTC Timestamp Capture
      11. 32.3.11 RTC Events
        1. 32.3.11.1 CPU Interrupt Event Publisher (CPU_INT)
        2. 32.3.11.2 Generic Event Publisher (GEN_EVENT)
    4. 32.4 RTC Registers
  35. 33IWDT
    1. 33.1 920
    2. 33.2 IWDT Clock Configuration
    3. 33.3 IWDT Period Selection
    4. 33.4 Debug Behavior of the IWDT
    5. 33.5 IWDT Registers
  36. 34Window Watchdog Timer (WWDT)
    1. 34.1 WWDT Overview
      1. 34.1.1 Watchdog Mode
      2. 34.1.2 Interval Timer Mode
    2. 34.2 WWDT Operation
      1. 34.2.1 Mode Selection
      2. 34.2.2 Clock Configuration
      3. 34.2.3 Low-Power Mode Behavior
      4. 34.2.4 Debug Behavior
      5. 34.2.5 WWDT Events
        1. 34.2.5.1 CPU Interrupt Event Publisher (CPU_INT)
    3. 34.3 WWDT Registers
  37. 35Debug
    1. 35.1 DEBUGSS Overview
      1. 35.1.1 Debug Interconnect
      2. 35.1.2 Physical Interface
      3. 35.1.3 Debug Access Ports
    2. 35.2 DEBUGSS Operation
      1. 35.2.1 Debug Features
        1. 35.2.1.1 Processor Debug
          1. 35.2.1.1.1 Breakpoint Unit (BPU)
          2. 35.2.1.1.2 Data Watchpoint and Trace Unit (DWT)
        2. 35.2.1.2 Peripheral Debug
        3. 35.2.1.3 EnergyTrace Technology
      2. 35.2.2 Behavior in Low Power Modes
      3. 35.2.3 Restricting Debug Access
      4. 35.2.4 Mailbox (DSSM)
        1. 35.2.4.1 DSSM Events
          1. 35.2.4.1.1 CPU Interrupt Event (CPU_INT)
        2. 35.2.4.2 Reference
    3. 35.3 DEBUGSS Registers
  38. 36Revision History

25.2.3.2 Flow Control

This section applies to UNICOMM-UART configurations which support the UART-FLOW-CONTROL feature.

In UART mode (CTL0.MODE set to 0), hardware flow control between two devices is accomplished by connecting the RTS output to the CTS input on the receiving device, and connecting the RTS output on the receiving device to the CTS input. The RTS output signal is active low, the CTS input expects a low signal on a send request as shown in Figure 25-10.

Flow ControlFigure 25-10 Flow Control

The CTS input controls the transmitter. The transmitter may only transmit data when the CTS input is asserted low. When RTS flow control is enabled, the RTS output signal indicates the state of the receive buffer/FIFO. CTS of the transmitting device remains asserted low until, the preprogrammed watermark level is reached in case of FIFO and receive buffer is full in case of a single buffer, indicating that the receiver has no space to store additional characters.

The CTSEN and RTSEN bits in the CTL0 register specify the flow control mode as shown in Table 25-61.

Table 25-4 Flow Control Enable
CTSENRTSENDescription
11RTS and CTS flow control enabled
10Only CTS flow control enabled
01Only RTS flow control enabled
00Both RTS and CTS flow control disabled

RTS bit can be driven by hardware or software. When RTSEN is 1 (i.e. hardware-controlled mode), the value of CTL0.RTS bit is ignored and RTS output signal is generated by hardware trigger levels as described below.

RTS flow control:

The RTS flow control logic is linked to the programmable receive FIFO watermark levels, it can be configured using UARTx.IFLS register. When RTS flow control is enabled, the RTS is asserted (low) until the receive FIFO is filled up to the watermark level. When the receive FIFO watermark level is reached, the RTS signal is de-asserted (high), indicating that there is no more room to receive any more data. The transmission of data is expected to cease after the current character has been transmitted. The RTS signal is reasserted (low) when data has been read out of the receive FIFO so that it is filled to less than the watermark level. If RTS flow control is disabled and the UART is still enabled, then data is received until the receive FIFO is full, or no more data is transmitted to it.

As the RTS signal is de-asserted when the FIFO watermark level is reached by putting the last received character into the FIFO. This means on a back to back transmit another character transfer could already been started by the sender. Therefore, in such cases the watermark level should be set to one level lower to ensure all data can be received and put into the FIFO.

CTS flow control:

If CTS flow control is enabled, then the transmitter checks the CTS signal before transmitting the next byte. If the CTS signal is asserted (low), it transmits the byte otherwise transmission does not occur. The data continues to be transmitted while CTS is asserted (low), and the transmit FIFO is not empty. If the transmit FIFO is empty and the CTS signal is asserted (low) no data is transmitted. If the CTS signal is de-asserted (high) and CTS flow control is enabled, then the current character transmission is completed before stopping. If CTS flow control is disabled and the UART is enabled, then the data continues to be transmitted until the transmit FIFO is empty.