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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 Event Recorder Setup Event Recorder Event Recorder Window Events Filtering Event Statistics Window Event Viewer Execution Profiler Instruction Trace Window System Analyzer Usage tips 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 and Cortex-M33 Nested Vector Interrupt Controller System Control and Configuration System Tick Timer Fault Reports Memory Protection Unit Security Attribution Unit 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 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

Serial Ports

The on-chip serial port is controlled with: S0TIME, S0IN, and S0OUT. S0IN and S0OUT represent the serial input and output streams on the CPU. S0TIME lets you specify whether the serial port timing instantaneous (STIME = 0) or the serial port timing is relative to the specified baudrate (SxTIME = 1). When S0TIME is 1, serial data displayed in the Serial window is output at the specified baudrate. When S0TIME is 0, serial data is displayed in the Serial window much more quickly.

Simulating serial input is just as easy as simulating digital input. Suppose you have an external serial device that inputs specific data periodically (every second). You can create a signal function that feeds the data into the CPU's serial port.

signal void serial_input (void) {
  while (1) {                                /* repeat forever */
    twatch (CLOCK);                          /* Delay for 1 second */

   S0IN = 'A';                               /* Send first character */
   twatch (CLOCK / 900);                     /* Delay for 1 character time */
                                             /* 900 is good for 9600 baud */
   S0IN = 'B';                               /* Send next character */
   twatch (CLOCK / 900);
   S0IN = 'C';                               /* Send final character */
  }                                          /* repeat */
}

When this signal function runs, it delays for 1 second, inputs 'A', 'B', and 'C' into the serial input line and repeats.

Serial output is simulated in a similar fashion using a user or signal function and a write access breakpoint as described above.

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