test

The receiving task has the lowest priority, so it will run only when both sending tasks are in the Blocked state. The sending tasks will enter the Blocked state only when the queue is full, so the receiving task will execute only when the queue is already full. Therefore, it always expects to receive data even when it does not specify a block time.

//code

#include "FreeRTOS.h"
#include "task.h"
#include "stm32f4xx.h"
#include "queue.h"
//Task1
// ----------------------------------------------------------------------------
QueueHandle_t xQueue;
static void vSenderTask( void *pvParameters )
{
int32_t lValueToSend;
BaseType_t xStatus;
/* Two instances of this task are created so the value that is sent to the
queue is passed in via the task parameter - this way each instance can use
a different value. The queue was created to hold values of type int32_t,
so cast the parameter to the required type. */
lValueToSend = ( int32_t ) pvParameters;
/* As per most tasks, this task is implemented within an infinite loop. */
for( ;; )
{
/* Send the value to the queue.
The first parameter is the queue to which data is being sent. The
queue was created before the scheduler was started, so before this task
started to execute.
The second parameter is the address of the data to be sent, in this case
the address of lValueToSend.
The third parameter is the Block time – the time the task should be kept
in the Blocked state to wait for space to become available on the queue
should the queue already be full. In this case a block time is not
specified because the queue should never contain more than one item, and
therefore never be full. */
xStatus = xQueueSendToBack( xQueue, &lValueToSend, 0 );
if( xStatus != pdPASS )
{
/* The send operation could not complete because the queue was full -
this must be an error as the queue should never contain more than
one item! */
//vPrintString( "Could not send to the queue.\r\n" );
}
}
}
static void vReceiverTask( void *pvParameters )
{
/* Declare the variable that will hold the values received from the queue. */
int32_t lReceivedValue;
BaseType_t xStatus;
const TickType_t xTicksToWait = pdMS_TO_TICKS( 100 );
/* This task is also defined within an infinite loop. */
for( ;; )
{
/* This call should always find the queue empty because this task will
immediately remove any data that is written to the queue. */
if( uxQueueMessagesWaiting( xQueue ) != 0 )
{
//vPrintString( "Queue should have been empty!\r\n" );
}
/* Receive data from the queue.
The first parameter is the queue from which data is to be received. The
queue is created before the scheduler is started, and therefore before this
task runs for the first time.
The second parameter is the buffer into which the received data will be
placed. In this case the buffer is simply the address of a variable that
has the required size to hold the received data.
The last parameter is the block time – the maximum amount of time that the
task will remain in the Blocked state to wait for data to be available
should the queue already be empty. */
xStatus = xQueueReceive( xQueue, &lReceivedValue, xTicksToWait );
if( xStatus == pdPASS )
{
/* Data was successfully received from the queue, print out the received
value. */
//vPrintStringAndNumber( "Received = ", lReceivedValue );
     if(lReceivedValue==100)
         GPIO_ToggleBits(GPIOD,GPIO_Pin_15);
     else if(lReceivedValue==200)
         GPIO_ToggleBits(GPIOD,GPIO_Pin_13);
}
else
{
/* Data was not received from the queue even after waiting for 100ms.
This must be an error as the sending tasks are free running and will be
continuously writing to the queue. */
//vPrintString( "Could not receive from the queue.\r\n" );
}
}
}

////Task2
//// ----------------------------------------------------------------------------
void GPIOInit(){
     GPIO_InitTypeDef g;
     g.GPIO_Pin = GPIO_Pin_12|GPIO_Pin_13|GPIO_Pin_14|GPIO_Pin_15; // ?? 12,13,14,15 ?
     g.GPIO_Mode = GPIO_Mode_OUT; // ???????
     g.GPIO_Speed = GPIO_Speed_100MHz; // ?? GPIO ???100 MHz
     RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE); // ?? GPIOD
     GPIO_Init(GPIOD, &g); // ??? GPIO D
}

/* Declare a variable of type QueueHandle_t. This is used to store the handle
to the queue that is accessed by all three tasks. */

int main( void )
{
/* The queue is created to hold a maximum of 5 values, each of which is
large enough to hold a variable of type int32_t. */
     GPIOInit();
xQueue = xQueueCreate( 5, sizeof( int32_t ) );
if( xQueue != NULL )
{
/* Create two instances of the task that will send to the queue. The task
parameter is used to pass the value that the task will write to the queue,
so one task will continuously write 100 to the queue while the other task
will continuously write 200 to the queue. Both tasks are created at
priority 1. */
xTaskCreate( vSenderTask, "Sender1", 1000, ( void * ) 100, 1, NULL );
xTaskCreate( vSenderTask, "Sender2", 1000, ( void * ) 200, 1, NULL );
/* Create the task that will read from the queue. The task is created with
priority 2, so above the priority of the sender tasks. */
xTaskCreate( vReceiverTask, "Receiver", 1000, NULL, 2, NULL );
/* Start the scheduler so the created tasks start executing. */
vTaskStartScheduler();
}
else
{
/* The queue could not be created. */
}
/* If all is well then main() will never reach here as the scheduler will
now be running the tasks. If main() does reach here then it is likely that
there was insufficient FreeRTOS heap memory available for the idle task to be
created. Chapter 2 provides more information on heap memory management. */
for( ;; );
}