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FreeRTOS V7.4.1 - Copyright (C) 2013 Real Time Engineers Ltd.
* *
* FreeRTOS tutorial books are available in pdf and paperback. *
* Complete, revised, and edited pdf reference manuals are also *
* available. *
* *
* Purchasing FreeRTOS documentation will not only help you, by *
* ensuring you get running as quickly as possible and with an *
* in-depth knowledge of how to use FreeRTOS, it will also help *
* the FreeRTOS project to continue with its mission of providing *
* professional grade, cross platform, de facto standard solutions *
* for microcontrollers - completely free of charge! *
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* >>> See for details. <<< *
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* Thank you for using FreeRTOS, and thank you for your support! *
* *
This file is part of the FreeRTOS distribution.
FreeRTOS is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License (version 2) as published by the
Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
>>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
distribute a combined work that includes FreeRTOS without being obliged to
provide the source code for proprietary components outside of the FreeRTOS
FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
details. You should have received a copy of the GNU General Public License
and the FreeRTOS license exception along with FreeRTOS; if not it can be
viewed here: and also obtained by
writing to Real Time Engineers Ltd., contact details for whom are available
on the FreeRTOS WEB site.
1 tab == 4 spaces!
* *
* Having a problem? Start by reading the FAQ "My application does *
* not run, what could be wrong?" *
* *
* *
* *
*************************************************************************** - Documentation, books, training, latest versions,
license and Real Time Engineers Ltd. contact details. - A selection of FreeRTOS ecosystem products,
including FreeRTOS+Trace - an indispensable productivity tool, and our new
fully thread aware and reentrant UDP/IP stack. - Real Time Engineers ltd license FreeRTOS to High
Integrity Systems, who sell the code with commercial support,
indemnification and middleware, under the OpenRTOS brand. - High Integrity Systems also provide a safety
engineered and independently SIL3 certified version for use in safety and
mission critical applications that require provable dependability.
* -NOTE- The Win32 port is a simulation (or is that emulation?) only! Do not
* expect to get real time behaviour from the Win32 port or this demo
* application. It is provided as a convenient development and demonstration
* test bed only. This was tested using Windows XP on a dual core laptop.
* In this example, one simulated millisecond will take approximately 40ms to
* execute, and the timing information in the FreeRTOS+Trace logs have no
* meaningful units. See the documentation page for the Windows simulator for
* an explanation of the slow timing:
* This is a simple FreeRTOS Windows simulator project that makes it easy to
* evaluate FreeRTOS+CLI and FreeRTOS+Trace on a standard desktop PC, without
* any external hardware or interfaces being required.
* To keep everything as simple as possible, the command line interface is
* accessed through a UDP socket on the default Windows loopback IP address of
* Full instructions are provided on the documentation page
* referenced above.
* Commands are provided to both start and stop a FreeRTOS+Trace recording.
* Stopping a recording will result in the recorded data being saved to the
* hard disk, ready for viewing in the FreeRTOS+Trace graphical user interface.
* Again, full instructions are provided on the documentation page referenced
* above.
* A queue send task and a queue receive task are defined in this file. The
* queue receive task spends most of its time blocked on the queue waiting for
* messages to arrive. The queue send task periodically sends a message to the
* queue, causing the queue receive task to exit the Blocked state. The
* priority of the queue receive task is above that of the queue send task, so
* it pre-empts the queue send task as soon as it leaves the Blocked state. It
* then consumes the message from the queue and prints "message received" to
* the screen before returning to block on the queue once again. This
* sequencing is clearly visible in the recorded FreeRTOS+Trace data.
* Finally, a trace monitoring task is also created that prints out a message
* when it determines that the status of the trace has changed since it last
* executed. It prints out a message when the trace has started, when the
* trace has stopped, and periodically when the trace is executing.
/* Standard includes. */
#include <stdio.h>
#include <stdint.h>
/* FreeRTOS includes. */
#include <FreeRTOS.h>
#include "task.h"
#include "queue.h"
/* FreeRTOS+Trace includes. */
#include "trcUser.h"
/* Priorities at which the tasks are created. */
/* The rate at which data is sent to the queue. The (simulated) 50ms value is
converted to ticks using the portTICK_RATE_MS constant. */
#define mainQUEUE_SEND_FREQUENCY_MS ( 50 / portTICK_RATE_MS )
/* The number of items the queue can hold. This is 1 as the receive task
will remove items as they are added, meaning the send task should always find
the queue empty. */
#define mainQUEUE_LENGTH ( 1 )
* The queue send and receive tasks as described in the comments at the top of
* this file.
static void prvQueueReceiveTask( void *pvParameters );
static void prvQueueSendTask( void *pvParameters );
* The task that implements the UDP command interpreter using FreeRTOS+CLI.
extern void vUDPCommandInterpreterTask( void *pvParameters );
* Register commands that can be used with FreeRTOS+CLI through the UDP socket.
* The commands are defined in CLI-commands.c.
extern void vRegisterCLICommands( void );
/* The queue used by both tasks. */
static xQueueHandle xQueue = NULL;
int main( void )
const uint32_t ulLongTime_ms = 250UL;
/* Create the queue used to pass messages from the queue send task to the
queue receive task. */
xQueue = xQueueCreate( mainQUEUE_LENGTH, sizeof( unsigned long ) );
/* Give the queue a name for the FreeRTOS+Trace log. */
vTraceSetQueueName( xQueue, "DemoQ" );
/* Start the two tasks as described in the comments at the top of this
file. */
xTaskCreate( prvQueueReceiveTask, /* The function that implements the task. */
( signed char * ) "Rx", /* The text name assigned to the task - for debug only as it is not used by the kernel. */
configMINIMAL_STACK_SIZE, /* The size of the stack to allocate to the task. Not actually used as a stack in the Win32 simulator port. */
NULL, /* The parameter passed to the task - not used in this example. */
mainQUEUE_RECEIVE_TASK_PRIORITY, /* The priority assigned to the task. */
NULL ); /* The task handle is not required, so NULL is passed. */
xTaskCreate( prvQueueSendTask, ( signed char * ) "TX", configMINIMAL_STACK_SIZE, NULL, mainQUEUE_SEND_TASK_PRIORITY, NULL );
/* Create the task that handles the CLI on a UDP port. The port number
is set using the configUDP_CLI_PORT_NUMBER setting in FreeRTOSConfig.h. */
xTaskCreate( vUDPCommandInterpreterTask, ( signed char * ) "CLI", configMINIMAL_STACK_SIZE, NULL, mainUDP_CLI_TASK_PRIORITY, NULL );
/* Create the task that monitors the trace recording status, printing
periodic information to the display. */
/* Register commands with the FreeRTOS+CLI command interpreter. */
/* Start the tasks and timer running. */
/* If all is well, the scheduler will now be running, and the following
line will never be reached. If the following line does execute, then
there was insufficient FreeRTOS heap memory available for the idle and/or
timer tasks to be created. See the memory management section on the
FreeRTOS web site for more details (this is standard text that is not not
really applicable to the Win32 simulator port). */
for( ;; )
Sleep( ulLongTime_ms );
static void prvQueueSendTask( void *pvParameters )
portTickType xNextWakeTime;
const unsigned long ulValueToSend = 100UL;
/* Remove warning about unused parameters. */
( void ) pvParameters;
/* Initialise xNextWakeTime - this only needs to be done once. */
xNextWakeTime = xTaskGetTickCount();
for( ;; )
/* Place this task in the blocked state until it is time to run again.
While in the Blocked state this task will not consume any CPU time. */
vTaskDelayUntil( &xNextWakeTime, mainQUEUE_SEND_FREQUENCY_MS );
/* Send to the queue - causing the queue receive task to unblock and
write a message to the display. 0 is used as the block time so the
sending operation will not block - it shouldn't need to block as the
queue should always be empty at this point in the code, and it is an
error if it is not. */
xQueueSend( xQueue, &ulValueToSend, 0U );
static void prvQueueReceiveTask( void *pvParameters )
unsigned long ulReceivedValue;
/* Remove warning about unused parameters. */
( void ) pvParameters;
for( ;; )
/* Wait until something arrives in the queue - this task will block
indefinitely provided INCLUDE_vTaskSuspend is set to 1 in
FreeRTOSConfig.h. */
xQueueReceive( xQueue, &ulReceivedValue, portMAX_DELAY );
/* To get here something must have been received from the queue, but
is it the expected value? If it is, write the message to the
display before looping back to block on the queue again. */
if( ulReceivedValue == 100UL )
printf( "Message received!\r\n" );
ulReceivedValue = 0U;
void vApplicationIdleHook( void )
const unsigned long ulMSToSleep = 5;
/* This function is called on each cycle of the idle task if
configUSE_IDLE_HOOK is set to 1 in FreeRTOSConfig.h. Sleep to reduce CPU
load. */
Sleep( ulMSToSleep );
void vAssertCalled( void )
const unsigned long ulLongSleep = 1000UL;
for( ;; )
Sleep( ulLongSleep );