Best way to pass simple data into a task

mittymcdoogle — Fri, 21 Aug 2015 21:15:58 GMT

I have a question about the best way to pass data into a task. I understand there is a message system for tasks, but I think the message system may be a bit overkill for what I'm trying to do. I have a board with multiple temperature sensors and I select which temperature sensor to read data from through a parameter I pass to 'temperatureRead' (see highlighted in red below). For example, to read temperature data from device 0, I call 'temperatureRead( 0 )'. To read temperature data from device 1, I call 'temperatureRead( 1 )'.

My question is whether or not my use of a global variable to specify the device (device 0, 1, 2, 3, 4, etc.) is the best way to accomplish what I am trying to accomplish. I like to avoid using global variables, but I also want a solution that is relatively simple.

void Temperature_task( uint32_t initial_data)

{

void *event_ptr; // Events are used to block tasks when not needed

if (_event_open("event.global", &event_ptr) != MQX_OK)

{

//TODO error message

}

while(TRUE)

{

// Go onto standby until a temp event is triggered

if (_event_wait_all_ticks(event_ptr, TEMP_EVENT_MASK, 0) != MQX_OK)

{

printf("\nEvent Wait failed");

_task_block();

}

// Lock the MUTEX to prevent too much communication across the I2C bus

if (_mutex_lock(&i2c_mutex) != MQX_OK)

{

printf("Mutex lock failed.\n");

_task_block();

}

temperatureRead( globalVariable );

_mutex_unlock(&i2c_mutex); // Unlock the I2C MUTEX so that other tasks can use the I2C bus

// Clear the event

if (_event_clear(event_ptr, TEMP_EVENT_MASK) != MQX_OK)

{

//TODO error message

} // end if( _event ...

} // end while(TRUE)

} // end Temperature_task

Thanks,

Mitty

Re: Best way to pass simple data into a task

Carlos_Musich — Thu, 27 Aug 2015 18:19:12 GMT

Hi Mitty,

the Mutex example shows how to pass parameters form a task to another. Please refer to the attached file.

If you have any question please let me know.

Regards,

Carlos

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Best way to pass simple data into a task

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