flash.c File Reference

#include <stdlib.h>
#include "FreeRTOS.h"
#include "task.h"
#include "partest.h"
#include "flash.h"

Go to the source code of this file.

Defines
#define	ledFLASH_RATE_BASE   ( ( portTickType ) 333 )
#define	ledNUMBER_OF_LEDS   ( 3 )
#define	ledSTACK_SIZE   configMINIMAL_STACK_SIZE
	This version of flash .c is for use on systems that have limited stack space and no display facilities.
Functions
static	portTASK_FUNCTION (vLEDFlashTask, pvParameters)
static	portTASK_FUNCTION_PROTO (vLEDFlashTask, pvParameters)
void	vStartLEDFlashTasks (unsigned portBASE_TYPE uxPriority)
Variables
static volatile unsigned portBASE_TYPE	uxFlashTaskNumber = 0

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Define Documentation

#define ledFLASH_RATE_BASE   ( ( portTickType ) 333 )

Definition at line 80 of file flash.c.

Referenced by portTASK_FUNCTION().

#define ledNUMBER_OF_LEDS   ( 3 )

Definition at line 79 of file flash.c.

Referenced by vStartLEDFlashTasks().

#define ledSTACK_SIZE   configMINIMAL_STACK_SIZE

This version of flash .c is for use on systems that have limited stack space and no display facilities.

The complete version can be found in the Demo/Common/Full directory.

Three tasks are created, each of which flash an LED at a different rate. The first LED flashes every 200ms, the second every 400ms, the third every 600ms.

The LED flash tasks provide instant visual feedback. They show that the scheduler is still operational.

Definition at line 78 of file flash.c.

Referenced by vStartLEDFlashTasks().

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Function Documentation

static portTASK_FUNCTION	(	vLEDFlashTask	,
		pvParameters
	)			[static]

Definition at line 104 of file flash.c.

References ledFLASH_RATE_BASE, portBASE_TYPE, portENTER_CRITICAL, portEXIT_CRITICAL, portTICK_RATE_MS, uxFlashTaskNumber, vParTestToggleLED(), vTaskDelayUntil(), and xTaskGetTickCount().

{
portTickType xFlashRate, xLastFlashTime;
unsigned portBASE_TYPE uxLED;

    /* The parameters are not used. */
    ( void ) pvParameters;

    /* Calculate the LED and flash rate. */
    portENTER_CRITICAL();
    {
        /* See which of the eight LED's we should use. */
        uxLED = uxFlashTaskNumber;

        /* Update so the next task uses the next LED. */
        uxFlashTaskNumber++;
    }
    portEXIT_CRITICAL();

    xFlashRate = ledFLASH_RATE_BASE + ( ledFLASH_RATE_BASE * ( portTickType ) uxLED );
    xFlashRate /= portTICK_RATE_MS;

    /* We will turn the LED on and off again in the delay period, so each
    delay is only half the total period. */
    xFlashRate /= ( portTickType ) 2;

    /* We need to initialise xLastFlashTime prior to the first call to 
    vTaskDelayUntil(). */
    xLastFlashTime = xTaskGetTickCount();

    for(;;)
    {
        /* Delay for half the flash period then turn the LED on. */
        vTaskDelayUntil( &xLastFlashTime, xFlashRate );
        vParTestToggleLED( uxLED );

        /* Delay for half the flash period then turn the LED off. */
        vTaskDelayUntil( &xLastFlashTime, xFlashRate );
        vParTestToggleLED( uxLED );
    }
} /*lint !e715 !e818 !e830 Function definition must be standard for task creation. */

static portTASK_FUNCTION_PROTO	(	vLEDFlashTask	,
		pvParameters
	)			[static]

void vStartLEDFlashTasks

(

unsigned portBASE_TYPE

uxPriority

)

Definition at line 91 of file flash.c.

References ledNUMBER_OF_LEDS, ledSTACK_SIZE, portBASE_TYPE, and xTaskCreate.

Referenced by main().

{
signed portBASE_TYPE xLEDTask;

    /* Create the three tasks. */
    for( xLEDTask = 0; xLEDTask < ledNUMBER_OF_LEDS; ++xLEDTask )
    {
        /* Spawn the task. */
        xTaskCreate( vLEDFlashTask, ( signed char * ) "LEDx", ledSTACK_SIZE, NULL, uxPriority, ( xTaskHandle * ) NULL );
    }
}

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Variable Documentation

volatile unsigned portBASE_TYPE uxFlashTaskNumber = 0 [static]

Definition at line 84 of file flash.c.

Referenced by portTASK_FUNCTION().