path: root/FreeRTOS/Demo/WIN32-MingW/main.c

/*
 * FreeRTOS V202211.00
 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * https://www.FreeRTOS.org
 * https://github.com/FreeRTOS
 *
 */

/******************************************************************************
 * This project provides two demo applications.  A simple blinky style project,
 * and a more comprehensive test and demo application.  The
 * mainCREATE_SIMPLE_BLINKY_DEMO_ONLY setting is used to select between the two.
 * The simply blinky demo is implemented and described in main_blinky.c.  The
 * more comprehensive test and demo application is implemented and described in
 * main_full.c.
 *
 * This file implements the code that is not demo specific, including the
 * hardware setup and FreeRTOS hook functions.
 *
 *******************************************************************************
 * NOTE: Windows will not be running the FreeRTOS demo threads continuously, so
 * do not expect to get real time behaviour from the FreeRTOS Windows port, or
 * this demo application.  Also, the timing information in the FreeRTOS+Trace
 * logs have no meaningful units.  See the documentation page for the Windows
 * port for further information:
 * https://www.FreeRTOS.org/FreeRTOS-Windows-Simulator-Emulator-for-Visual-Studio-and-Eclipse-MingW.html
 *

 *
 *******************************************************************************
 */

/* Standard includes. */
#include <stdio.h>
#include <stdlib.h>
#include <conio.h>

/* FreeRTOS kernel includes. */
#include "FreeRTOS.h"
#include "task.h"

/* This project provides two demo applications.  A simple blinky style demo
application, and a more comprehensive test and demo application.  The
mainCREATE_SIMPLE_BLINKY_DEMO_ONLY setting is used to select between the two.

If mainCREATE_SIMPLE_BLINKY_DEMO_ONLY is 1 then the blinky demo will be built.
The blinky demo is implemented and described in main_blinky.c.

If mainCREATE_SIMPLE_BLINKY_DEMO_ONLY is not 1 then the comprehensive test and
demo application will be built.  The comprehensive test and demo application is
implemented and described in main_full.c. */
#define mainCREATE_SIMPLE_BLINKY_DEMO_ONLY    0

/* This demo uses heap_5.c, and these constants define the sizes of the regions
that make up the total heap.  heap_5 is only used for test and example purposes
as this demo could easily create one large heap region instead of multiple
smaller heap regions - in which case heap_4.c would be the more appropriate
choice.  See http://www.freertos.org/a00111.html for an explanation. */
#define mainREGION_1_SIZE    8201
#define mainREGION_2_SIZE    40905
#define mainREGION_3_SIZE    50007

/* This demo allows for users to perform actions with the keyboard. */
#define mainNO_KEY_PRESS_VALUE                -1
#define mainOUTPUT_TRACE_KEY                  't'
#define mainINTERRUPT_NUMBER_KEYBOARD         3

/* This demo allows to save a trace file. */
#define mainTRACE_FILE_NAME                   "Trace.dump"

/*-----------------------------------------------------------*/

/*
 * main_blinky() is used when mainCREATE_SIMPLE_BLINKY_DEMO_ONLY is set to 1.
 * main_full() is used when mainCREATE_SIMPLE_BLINKY_DEMO_ONLY is set to 0.
 */
extern void main_blinky( void );
extern void main_full( void );

/*
 * Only the comprehensive demo uses application hook (callback) functions.  See
 * https://www.FreeRTOS.org/a00016.html for more information.
 */
void vFullDemoTickHookFunction( void );
void vFullDemoIdleFunction( void );

/*
 * This demo uses heap_5.c, so start by defining some heap regions.  It is not
 * necessary for this demo to use heap_5, as it could define one large heap
 * region.  Heap_5 is only used for test and example purposes.  See
 * https://www.FreeRTOS.org/a00111.html for an explanation.
 */
static void  prvInitialiseHeap( void );

/*
 * Performs a few sanity checks on the behaviour of the vPortGetHeapStats()
 * function.
 */
static void prvExerciseHeapStats( void );

/*
 * Prototypes for the standard FreeRTOS application hook (callback) functions
 * implemented within this file.  See http://www.freertos.org/a00016.html .
 */
void vApplicationMallocFailedHook( void );
void vApplicationIdleHook( void );
void vApplicationStackOverflowHook( TaskHandle_t pxTask, char *pcTaskName );
void vApplicationTickHook( void );
void vApplicationGetIdleTaskMemory( StaticTask_t **ppxIdleTaskTCBBuffer, StackType_t **ppxIdleTaskStackBuffer, uint32_t *pulIdleTaskStackSize );
void vApplicationGetTimerTaskMemory( StaticTask_t **ppxTimerTaskTCBBuffer, StackType_t **ppxTimerTaskStackBuffer, uint32_t *pulTimerTaskStackSize );

/*
 * Writes trace data to a disk file when the trace recording is stopped.
 * This function will simply overwrite any trace files that already exist.
 */
static void prvSaveTraceFile( void );

/*
 * Windows thread function to capture keyboard input from outside of the
 * FreeRTOS simulator. This thread passes data safely into the FreeRTOS
 * simulator using a stream buffer.
 */
static DWORD WINAPI prvWindowsKeyboardInputThread( void * pvParam );

/*
 * Interrupt handler for when keyboard input is received.
 */
static uint32_t prvKeyboardInterruptHandler( void );

/*
 * Keyboard interrupt handler for the blinky demo.
 */
extern void vBlinkyKeyboardInterruptHandler( int xKeyPressed );

/*-----------------------------------------------------------*/

/* When configSUPPORT_STATIC_ALLOCATION is set to 1 the application writer can
use a callback function to optionally provide the memory required by the idle
and timer tasks.  This is the stack that will be used by the timer task.  It is
declared here, as a global, so it can be checked by a test that is implemented
in a different file. */
StackType_t uxTimerTaskStack[ configTIMER_TASK_STACK_DEPTH ];

/* Thread handle for the keyboard input Windows thread. */
static HANDLE xWindowsKeyboardInputThreadHandle = NULL;

/* This stores the last key pressed that has not been handled.
 * Keyboard input is retrieved by the prvWindowsKeyboardInputThread
 * Windows thread and stored here. This is then read by the idle
 * task and handled appropriately. */
static int xKeyPressed = mainNO_KEY_PRESS_VALUE;

/*-----------------------------------------------------------*/

int main( void )
{
    /* Set interrupt handler for keyboard input. */
    vPortSetInterruptHandler( mainINTERRUPT_NUMBER_KEYBOARD, prvKeyboardInterruptHandler );

    /* Start keyboard input handling thread. */
    xWindowsKeyboardInputThreadHandle = CreateThread(
        NULL,                          /* Pointer to thread security attributes. */
        0,                             /* Initial thread stack size, in bytes. */
        prvWindowsKeyboardInputThread, /* Pointer to thread function. */
        NULL,                          /* Argument for new thread. */
        0,                             /* Creation flags. */
        NULL);

    fflush( stdout );

    /* Use the cores that are not used by the FreeRTOS tasks. */
    SetThreadAffinityMask( xWindowsKeyboardInputThreadHandle, ~0x01u );

    /* This demo uses heap_5.c, so start by defining some heap regions.  heap_5
    is only used for test and example reasons.  Heap_4 is more appropriate.  See
    http://www.freertos.org/a00111.html for an explanation. */
    prvInitialiseHeap();

    /* Do not include trace code when performing a code coverage analysis. */
    #if( projCOVERAGE_TEST != 1 )
    {
        /* Initialise the trace recorder.  Use of the trace recorder is optional.
        See http://www.FreeRTOS.org/trace for more information. */
        configASSERT( xTraceInitialize() == TRC_SUCCESS );

        /* Start the trace recording - the recording is written to a file if
        configASSERT() is called. */
        printf(
                "Trace started.\r\n"
                "Note that the trace output uses the ring buffer mode, meaning that the output trace\r\n"
                "will only be the most recent data able to fit within the trace recorder buffer.\r\n\r\n"
                "The trace will be dumped to the file \"%s\" whenever a call to configASSERT()\r\n"
                "fails or the \'%c\' key is pressed.\r\n"
                "Note that key presses cannot be captured in the Eclipse console, so for key presses to work\r\n"
                "you will have to run this demo in a Windows console.\r\n\r\n",
                mainTRACE_FILE_NAME, mainOUTPUT_TRACE_KEY );
        fflush( stdout );
        configASSERT( xTraceEnable( TRC_START ) == TRC_SUCCESS );
    }
    #endif

    /* The mainCREATE_SIMPLE_BLINKY_DEMO_ONLY setting is described at the top
    of this file. */
    #if ( mainCREATE_SIMPLE_BLINKY_DEMO_ONLY == 1 )
    {
        main_blinky();
    }
    #else
    {
        main_full();
    }
    #endif

    return 0;
}
/*-----------------------------------------------------------*/

void vApplicationMallocFailedHook( void )
{
    /* vApplicationMallocFailedHook() will only be called if
    configUSE_MALLOC_FAILED_HOOK is set to 1 in FreeRTOSConfig.h. It is a hook
    function that will get called if a call to pvPortMalloc() fails.
    pvPortMalloc() is called internally by the kernel whenever a task, queue,
    timer or semaphore is created.  It is also called by various parts of the
    demo application. If heap_1.c, heap_2.c or heap_4.c is being used, then the
    size of the heap available to pvPortMalloc() is defined by
    configTOTAL_HEAP_SIZE in FreeRTOSConfig.h, and the xPortGetFreeHeapSize()
    API function can be used to query the size of free heap space that remains
    (although it does not provide information on how the remaining heap might be
    fragmented).  See http://www.freertos.org/a00111.html for more
    information. */
    vAssertCalled( __LINE__, __FILE__ );
}
/*-----------------------------------------------------------*/

void vApplicationIdleHook( void )
{
    /* vApplicationIdleHook() will only be called if configUSE_IDLE_HOOK is set
    to 1 in FreeRTOSConfig.h.  It will be called on each iteration of the idle
    task.  It is essential that code added to this hook function never attempts
    to block in any way (for example, call xQueueReceive() with a block time
    specified, or call vTaskDelay()).  If application tasks make use of the
    vTaskDelete() API function to delete themselves then it is also important
    that vApplicationIdleHook() is permitted to return to its calling function,
    because it is the responsibility of the idle task to clean up memory
    allocated by the kernel to any task that has since deleted itself. */

    #if ( mainCREATE_SIMPLE_BLINKY_DEMO_ONLY != 1 )
    {
        /* Call the idle task processing used by the full demo.  The simple
        blinky demo does not use the idle task hook. */
        vFullDemoIdleFunction();
    }
    #endif
}
/*-----------------------------------------------------------*/

void vApplicationStackOverflowHook( TaskHandle_t pxTask, char *pcTaskName )
{
    ( void ) pcTaskName;
    ( void ) pxTask;

    /* Run time stack overflow checking is performed if
    configCHECK_FOR_STACK_OVERFLOW is defined to 1 or 2.  This hook
    function is called if a stack overflow is detected.  This function is
    provided as an example only as stack overflow checking does not function
    when running the FreeRTOS Windows port. */
    vAssertCalled( __LINE__, __FILE__ );
}
/*-----------------------------------------------------------*/

void vApplicationTickHook( void )
{
    /* This function will be called by each tick interrupt if
    configUSE_TICK_HOOK is set to 1 in FreeRTOSConfig.h.  User code can be
    added here, but the tick hook is called from an interrupt context, so
    code must not attempt to block, and only the interrupt safe FreeRTOS API
    functions can be used (those that end in FromISR()). */

    #if ( mainCREATE_SIMPLE_BLINKY_DEMO_ONLY != 1 )
    {
        vFullDemoTickHookFunction();
    }
    #endif /* mainCREATE_SIMPLE_BLINKY_DEMO_ONLY */
}
/*-----------------------------------------------------------*/

void vApplicationDaemonTaskStartupHook( void )
{
    /* This function will be called once only, when the daemon task starts to
    execute (sometimes called the timer task). This is useful if the
    application includes initialisation code that would benefit from executing
    after the scheduler has been started. */
}
/*-----------------------------------------------------------*/

void vAssertCalled( unsigned long ulLine, const char * const pcFileName )
{
volatile uint32_t ulSetToNonZeroInDebuggerToContinue = 0;

    /* Called if an assertion passed to configASSERT() fails.  See
    http://www.freertos.org/a00110.html#configASSERT for more information. */

    /* Parameters are not used. */
    ( void ) ulLine;
    ( void ) pcFileName;


    taskENTER_CRITICAL();
    {
        printf("ASSERT! Line %ld, file %s, GetLastError() %ld\r\n", ulLine, pcFileName, GetLastError());
        fflush( stdout );

        #if( projCOVERAGE_TEST != 1 )
        {
            /* Stop the trace recording. */
            ( void ) xTraceDisable();
            prvSaveTraceFile();
        }
        #endif

        /* You can step out of this function to debug the assertion by using
        the debugger to set ulSetToNonZeroInDebuggerToContinue to a non-zero
        value. */
        while( ulSetToNonZeroInDebuggerToContinue == 0 )
        {
            __asm volatile( "NOP" );
            __asm volatile( "NOP" );
        }

        #if( projCOVERAGE_TEST != 1 )
        {
            /* Re-enable recording */
            ( void ) xTraceEnable( TRC_START );
        }
        #endif
    }
    taskEXIT_CRITICAL();
}
/*-----------------------------------------------------------*/

static void prvSaveTraceFile( void )
{
    /* Tracing is not used when code coverage analysis is being performed. */
    #if( projCOVERAGE_TEST != 1 )
    {
        FILE* pxOutputFile;
		
        pxOutputFile = fopen( mainTRACE_FILE_NAME, "wb");

        if( pxOutputFile != NULL )
        {
            fwrite( RecorderDataPtr, sizeof( RecorderDataType ), 1, pxOutputFile );
            fclose( pxOutputFile );
            printf( "\r\nTrace output saved to %s\r\n", mainTRACE_FILE_NAME );
            fflush( stdout );
        }
        else
        {
            printf( "\r\nFailed to create trace dump file\r\n" );
            fflush( stdout );
        }
    }
    #endif
}
/*-----------------------------------------------------------*/

static void  prvInitialiseHeap( void )
{
/* The Windows demo could create one large heap region, in which case it would
be appropriate to use heap_4.  However, purely for demonstration purposes,
heap_5 is used instead, so start by defining some heap regions.  No
initialisation is required when any other heap implementation is used.  See
http://www.freertos.org/a00111.html for more information.

The xHeapRegions structure requires the regions to be defined in start address
order, so this just creates one big array, then populates the structure with
offsets into the array - with gaps in between and messy alignment just for test
purposes. */
static uint8_t ucHeap[ configTOTAL_HEAP_SIZE ];
volatile uint32_t ulAdditionalOffset = 19; /* Just to prevent 'condition is always true' warnings in configASSERT(). */
HeapStats_t xHeapStats;
const HeapRegion_t xHeapRegions[] =
{
    /* Start address with dummy offsets                       Size */
    { ucHeap + 1,                                             mainREGION_1_SIZE },
    { ucHeap + 15 + mainREGION_1_SIZE,                        mainREGION_2_SIZE },
    { ucHeap + 19 + mainREGION_1_SIZE + mainREGION_2_SIZE,    mainREGION_3_SIZE },
    { NULL, 0 }
};

    /* Sanity check that the sizes and offsets defined actually fit into the
    array. */
    configASSERT( ( ulAdditionalOffset + mainREGION_1_SIZE + mainREGION_2_SIZE + mainREGION_3_SIZE ) < configTOTAL_HEAP_SIZE );

    /* Prevent compiler warnings when configASSERT() is not defined. */
    ( void ) ulAdditionalOffset;

    /* The heap has not been initialised yet so expect stats to all be zero. */
    vPortGetHeapStats( &xHeapStats );

    vPortDefineHeapRegions( xHeapRegions );

    /* Sanity check vTaskGetHeapStats(). */
    prvExerciseHeapStats();
}
/*-----------------------------------------------------------*/

static void prvExerciseHeapStats( void )
{
HeapStats_t xHeapStats;
size_t xInitialFreeSpace = xPortGetFreeHeapSize(), xMinimumFreeBytes;
size_t xMetaDataOverhead, i;
void *pvAllocatedBlock;
const size_t xArraySize = 5, xBlockSize = 1000UL;
void *pvAllocatedBlocks[ xArraySize ];

    /* Check heap stats are as expected after initialisation but before any
    allocations. */
    vPortGetHeapStats( &xHeapStats );

    /* Minimum ever free bytes remaining should be the same as the total number
    of bytes as nothing has been allocated yet. */
    configASSERT( xHeapStats.xMinimumEverFreeBytesRemaining == xHeapStats.xAvailableHeapSpaceInBytes );
    configASSERT( xHeapStats.xMinimumEverFreeBytesRemaining == xInitialFreeSpace );

    /* Nothing has been allocated or freed yet. */
    configASSERT( xHeapStats.xNumberOfSuccessfulAllocations == 0 );
    configASSERT( xHeapStats.xNumberOfSuccessfulFrees == 0 );

    /* Allocate a 1000 byte block then measure what the overhead of the
    allocation in regards to how many bytes more than 1000 were actually
    removed from the heap in order to store metadata about the allocation. */
    pvAllocatedBlock = pvPortMalloc( xBlockSize );
    configASSERT( pvAllocatedBlock );
    xMetaDataOverhead = ( xInitialFreeSpace - xPortGetFreeHeapSize() ) - xBlockSize;

    /* Free the block again to get back to where we started. */
    vPortFree( pvAllocatedBlock );
    vPortGetHeapStats( &xHeapStats );
    configASSERT( xHeapStats.xAvailableHeapSpaceInBytes == xInitialFreeSpace );
    configASSERT( xHeapStats.xNumberOfSuccessfulAllocations == 1 );
    configASSERT( xHeapStats.xNumberOfSuccessfulFrees == 1 );

    /* Allocate blocks checking some stats value on each allocation. */
    for( i = 0; i < xArraySize; i++ )
    {
        pvAllocatedBlocks[ i ] = pvPortMalloc( xBlockSize );
        configASSERT( pvAllocatedBlocks[ i ] );
        vPortGetHeapStats( &xHeapStats );
        configASSERT( xHeapStats.xMinimumEverFreeBytesRemaining == ( xInitialFreeSpace - ( ( i + 1 ) * ( xBlockSize + xMetaDataOverhead ) ) ) );
        configASSERT( xHeapStats.xMinimumEverFreeBytesRemaining == xHeapStats.xAvailableHeapSpaceInBytes );
        configASSERT( xHeapStats.xNumberOfSuccessfulAllocations == ( 2Ul + i ) );
        configASSERT( xHeapStats.xNumberOfSuccessfulFrees == 1 ); /* Does not increase during allocations. */
    }

    configASSERT( xPortGetFreeHeapSize() == xPortGetMinimumEverFreeHeapSize() );
    xMinimumFreeBytes = xPortGetFreeHeapSize();

    /* Free the blocks again. */
    for( i = 0; i < xArraySize; i++ )
    {
        vPortFree( pvAllocatedBlocks[ i ] );
        vPortGetHeapStats( &xHeapStats );
        configASSERT( xHeapStats.xAvailableHeapSpaceInBytes == ( xInitialFreeSpace - ( ( ( xArraySize - i - 1 ) * ( xBlockSize + xMetaDataOverhead ) ) ) ) );
        configASSERT( xHeapStats.xNumberOfSuccessfulAllocations == ( xArraySize + 1 ) ); /* Does not increase during frees. */
        configASSERT( xHeapStats.xNumberOfSuccessfulFrees == ( 2UL + i ) );
    }

    /* The minimum ever free heap size should not change as blocks are freed. */
    configASSERT( xMinimumFreeBytes == xPortGetMinimumEverFreeHeapSize() );
}
/*-----------------------------------------------------------*/

/* configUSE_STATIC_ALLOCATION is set to 1, so the application must provide an
implementation of vApplicationGetIdleTaskMemory() to provide the memory that is
used by the Idle task. */
void vApplicationGetIdleTaskMemory( StaticTask_t **ppxIdleTaskTCBBuffer, StackType_t **ppxIdleTaskStackBuffer, uint32_t *pulIdleTaskStackSize )
{
/* If the buffers to be provided to the Idle task are declared inside this
function then they must be declared static - otherwise they will be allocated on
the stack and so not exists after this function exits. */
static StaticTask_t xIdleTaskTCB;
static StackType_t uxIdleTaskStack[ configMINIMAL_STACK_SIZE ];

    /* Pass out a pointer to the StaticTask_t structure in which the Idle task's
    state will be stored. */
    *ppxIdleTaskTCBBuffer = &xIdleTaskTCB;

    /* Pass out the array that will be used as the Idle task's stack. */
    *ppxIdleTaskStackBuffer = uxIdleTaskStack;

    /* Pass out the size of the array pointed to by *ppxIdleTaskStackBuffer.
    Note that, as the array is necessarily of type StackType_t,
    configMINIMAL_STACK_SIZE is specified in words, not bytes. */
    *pulIdleTaskStackSize = configMINIMAL_STACK_SIZE;
}

/*-----------------------------------------------------------*/

/* configUSE_STATIC_ALLOCATION and configUSE_TIMERS are both set to 1, so the
application must provide an implementation of vApplicationGetTimerTaskMemory()
to provide the memory that is used by the Timer service task. */
void vApplicationGetTimerTaskMemory( StaticTask_t **ppxTimerTaskTCBBuffer, StackType_t **ppxTimerTaskStackBuffer, uint32_t *pulTimerTaskStackSize )
{
/* If the buffers to be provided to the Timer task are declared inside this
function then they must be declared static - otherwise they will be allocated on
the stack and so not exists after this function exits. */
static StaticTask_t xTimerTaskTCB;

    /* Pass out a pointer to the StaticTask_t structure in which the Timer
    task's state will be stored. */
    *ppxTimerTaskTCBBuffer = &xTimerTaskTCB;

    /* Pass out the array that will be used as the Timer task's stack. */
    *ppxTimerTaskStackBuffer = uxTimerTaskStack;

    /* Pass out the size of the array pointed to by *ppxTimerTaskStackBuffer.
    Note that, as the array is necessarily of type StackType_t,
    configMINIMAL_STACK_SIZE is specified in words, not bytes. */
    *pulTimerTaskStackSize = configTIMER_TASK_STACK_DEPTH;
}

/*-----------------------------------------------------------*/

/*
 * Interrupt handler for when keyboard input is received.
 */
static uint32_t prvKeyboardInterruptHandler( void )
{
    /* Handle keyboard input. */
    switch ( xKeyPressed )
    {
    case mainNO_KEY_PRESS_VALUE:
        break;
    case mainOUTPUT_TRACE_KEY:
        #if( projCOVERAGE_TEST != 1 )
        {
            /* Saving the trace file requires Windows system calls, so enter a critical
             * section to prevent deadlock or errors resulting from calling a Windows
             * system call from within the FreeRTOS simulator. */
            portENTER_CRITICAL();
            {
                ( void ) xTraceDisable();
                prvSaveTraceFile();
                ( void ) xTraceEnable( TRC_START );
            }
            portEXIT_CRITICAL();
        }
        #endif
        break;
    default:
        #if ( mainCREATE_SIMPLE_BLINKY_DEMO_ONLY == 1 )
            {
                /* Call the keyboard interrupt handler for the blinky demo. */
                vBlinkyKeyboardInterruptHandler( xKeyPressed );
            }
        #endif
        break;
    }

    /* This interrupt does not require a context switch so return pdFALSE */
    return pdFALSE;
}

/*-----------------------------------------------------------*/

/*
 * Windows thread function to capture keyboard input from outside of the
 * FreeRTOS simulator. This thread passes data into the simulator using
 * an integer.
 */
static DWORD WINAPI prvWindowsKeyboardInputThread( void * pvParam )
{
    ( void ) pvParam;

    for ( ; ; )
    {
        /* Block on acquiring a key press */
        xKeyPressed = _getch();

        /* Notify FreeRTOS simulator that there is a keyboard interrupt.
         * This will trigger prvKeyboardInterruptHandler.
         */
        vPortGenerateSimulatedInterrupt( mainINTERRUPT_NUMBER_KEYBOARD );
    }

    /* Should not get here, report negative exit status. */
    return -1;
}

/*-----------------------------------------------------------*/

/* The below code is used by the trace recorder for timing. */
static uint32_t ulEntryTime = 0;

void vTraceTimerReset( void )
{
    ulEntryTime = xTaskGetTickCount();
}

uint32_t uiTraceTimerGetFrequency( void )
{
    return configTICK_RATE_HZ;
}

uint32_t uiTraceTimerGetValue( void )
{
    return( xTaskGetTickCount() - ulEntryTime );
}