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µVision User's Guide

About µVision User Interface Creating Applications Debugging Start Debugging Start Energy Measurement without Debug Application Program Execution Debug Windows and Dialogs Breakpoints Window Call Stack and Locals Window Code Coverage Command Window Component Viewer Disassembly Window Editor Window Event Recorder Setup Event Recorder Event Recorder Window Events Filtering Event Statistics Window Post-mortem Analysis Event Viewer Execution Profiler Instruction Trace Window System Analyzer Usage tips Save System Analyzer Contents Statistics Restrictions Logic Analyzer Setup Setup in Detail Restrictions Cortex-M Trace Configuration Memory Map Memory Window Performance Analyzer Registers Window Serial Window Debug (printf) Viewer Symbols Window System Viewer Adding System Viewer Windows System and Thread Viewer Thread States Toolbox Trace Data Window Trace Navigation Trace Exceptions Event Counters ULINKplus Window Watch Window Core Peripherals Cortex-M0 and Cortex-M0+ Nested Vector Interrupt Controller System Control and Configuration System Tick Timer Fault Reports (Cortex-M0+ only) Cortex-M3, Cortex-M4, and Cortex-M7 Nested Vector Interrupt Controller System Control and Configuration System Tick Timer Fault Reports Memory Protection Unit Cortex-M23/M33/M35P and Cortex-M55 Nested Vector Interrupt Controller System Control and Configuration System Tick Timer Fault Reports Memory Protection Unit Security Attribution Unit M-Profile Vector Extension (MVE) Debug Scripting Expressions Constants System Variables Peripheral Variables I/O Ports Serial Ports Program Variables (Symbols) Fully Qualified Symbols Non-Qualified Symbols Literal Symbols Using Symbols Line Numbers Bit Addresses Type Specifications Memory Attribution Specifiers Operators Differences between µVision and C Expression Examples Code and Data Trace (Cortex-M) Trace Features Configuring Trace Tracepoint Expressions Tracepoint Intrinsics Tracepoint Limitations Tracepoint Marks Tips and Tricks Review Peripherals and CPU Configuration Simulate I/O Ports Simulate Interrupts and Clock Inputs Simulate external I/O Devices Assign Serial I/O to a PC COM Port Check Illegal Memory Access Command Input from File Preset I/O Ports or Memory Contents Write Debug Output to a File Keyboard Shortcuts TPIU Initialization after RESET (Cortex-M) Prevent Opening Files Show Japanese Messages Debug Commands Debug Functions Simulation Flash Programming Dialogs Utilities Command Line Example Programs Appendix

Registers Window

The Registers window shows and allows modifying the content of registers, lists microcontroller operation modes, and system and internal states.

Project Workspace ButtonThe toolbar button or the menu View - Registers Window opens the window.

Registers Window


Register Lists operation modes, register names, and CPU states.
Value Shows the register content. Double-click on a value (or click on the value and press F2) to modify the content.
  • CPUs that have enabled TrustZone for Armv8-M, show the Secure and Non-Secure operation modes. This mode is also displayed in the Status Bar.
  • The currently active mode is highlighted in black.
  • Modified registers are highlighted in blue.
  • CPUs with Floating Point Unit (FPU) show the corresponding registers in the FPU group.
  • CPUs with Cortex-M Vector Extension (MVE) show the VPR register in the MVE group.
  • Refresh the window content by halting program execution or clicking Update Windows from the Toolbox.

States Register

The register field States shows:

  • In Simulator mode:
    The approximated cycle value. The memory system is not simulated. Thus, extra cycles required for memory accesses are not taken into account.
  • For Cortex-M0/M0+/M1/M23
    Not displayed.
  • For Cortex-M3/M4/M7/M33/M35P/M55
    Represents the target cycle counter, which is updated from the CoreSight Data Watchpoint and Trace unit Cycle Count (DWT_CYCCNT) register.

Sec Register

The register field Sec shows the elapsed time (in seconds) since debugging started and is based on the same information as States. The value is identical with the entry t0 of the Status Bar. Not displayed for Cortex-M0/M0+/M1/M23 devices.

See Also:

Information about additional counters can be found in:


  • The window content depends on the device in use. The picture above is an example from a Cortex-M3 processor based device.
  • For Armv8-M implementations with Main and Security Extensions, the cycle counter does not increment if the CPU is in Secure state and DWT_CTRL.CYCDISS is set to 1.
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