blink_task.c

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/**************************************************
 * Texas A&M University
 * Electronic Systems Engineering Technology
 * ENTC-489 Embedded Real Time Software Development
 * Author: willey
 * File: blink_task.c
 **************************************************/
#include <stdint.h>
#include <stdbool.h>
#include "blink.h"

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

#define BLINK_TASK_STACK_SIZE (OS_TASK_IDLE_STK_SIZE+0)  
/* Priority definitions, Yellow blinks fastest so should be the highest
 * priority task (lowest numberic value) */
#define BLUE_PRIO 18
#define RED_PRIO 19
#define YELLOW_PRIO 14

#define YELLOW_FREQ (2 * MILLI_HZ_PER_HZ)   
#define BLUE_RED_FREQ (1 * MILLI_HZ_PER_HZ) 
#define RED_START_DELAY ((BLUE_RED_FREQ * OS_TICKS_PER_SEC) / (2 * MILLI_HZ_PER_HZ))

/**************************************************/
static led_data_t blue_config =
{  /* priority, led, delay, freq */
    BLUE_PRIO, BLUE_LED, 0, BLUE_RED_FREQ
};

static led_data_t red_config =
{  /* priority, led, delay, freq */
    RED_PRIO, RED_LED, RED_START_DELAY, BLUE_RED_FREQ
};

static led_data_t yellow_config =
{  /* priority, led, delay, freq */
    YELLOW_PRIO, YELLOW_LED, 0, YELLOW_FREQ
};

/**************************************************/
static OS_STK blue_task_stk[BLINK_TASK_STACK_SIZE];
static OS_STK red_task_stk[BLINK_TASK_STACK_SIZE];
static OS_STK yellow_task_stk[BLINK_TASK_STACK_SIZE];

/**************************************************/
void blink_task( void *parms  )
{
    led_data_t info;
    uint32_t led_on, blink_delay;
    volatile uint32_t *led_port;

    /* using this intermidiate pointer so we only have to cast once */
    info = *((led_data_t *)parms);

    /* get the address of the pin we will be using */
    switch ( info.led_position )
    {
    case RED_LED:
        led_on = RED_LED_PIN;
        led_port = &(LAUNCH_OUTPUT_DATA);
        break;

    case GREEN_LED:
        led_on = GREEN_LED_PIN;
        led_port = &(LAUNCH_OUTPUT_DATA);
        break;

    case BLUE_LED:
        led_on = BLUE_LED_PIN;
        led_port = &(LAUNCH_OUTPUT_DATA);
        break;

    case YELLOW_LED:
        led_on = YELLOW_LED_PIN;
        led_port = &(BOOST_OUTPUT_DATA);
        break;

    default:
        /* we don't know what to toggle, so we will stop the task here */
        OSTaskSuspend(info.prio);
        break;
    } /* switch ( info->led_position ) */

    /* compute the blink delay just once, so we don't have to do this
     * calculation over and over again. We get the frequency in milli Hz, and
     * compute a time delay that is half that to get our 50% duty cycle */
    blink_delay = ((OS_TICKS_PER_SEC * MILLI_HZ_PER_HZ) / info.blink_freq) / 2L;

    /* delay before we turn the LED on, remeber start_delay is in milliseconds */
    OSTimeDly((OS_TICKS_PER_SEC * info.start_delay) / (uint32_t)1000);
    *led_port = led_on;

    while (1)
    {
        /* to get a 50% duty cycle we have to divide the time in half
         * also remember that the frequency is in kHz */
        OSTimeDly(blink_delay);

        /* toggle the LED */
        *led_port ^= led_on;
    } /* while (1) */

} /* blink_task () */

/**************************************************/
void start_blinking ( void )
{
    INT8U os_rval;  /* used to store return values from OS calls */

    os_rval = OSTaskCreate(blink_task,&blue_config,&blue_task_stk[BLINK_TASK_STACK_SIZE-1],blue_config.prio);
    if (os_rval != OS_ERR_NONE)
    {
        while (1)
        {
            /* something went badly wrong */
        }
    }
    os_rval = OSTaskCreate(blink_task,&red_config,&red_task_stk[BLINK_TASK_STACK_SIZE-1],red_config.prio);
    if (os_rval != OS_ERR_NONE)
    {
        while (1)
        {
            /* something went badly wrong */
        }
    }
    os_rval = OSTaskCreate(blink_task,&yellow_config,&yellow_task_stk[BLINK_TASK_STACK_SIZE-1],yellow_config.prio);
    if (os_rval != OS_ERR_NONE)
    {
        while (1)
        {
            /* something went badly wrong */
        }
    }
} /* start_blinking() */

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