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TIRTOS gpio interrupt example problem

BillP
Intellectual 585 points
Other Parts Discussed in Thread: SYSBIOS

I am working through the TIRTOS examples to learn TI-RTOS, SYSBIOS, XDCTOOLS, etc.  I am on the GPIO interrupt example and I have a problem.  I am using CCS v5.3, the latest version of TIRTOS and a DK-LM3S9B96 dev kit board. 

I am able to recompile, load, and download the .out file to the board and run it in debug mode.  When I hit the user button slowly, the led toggles (as it should).  However, when I hit the user button faster, the led misses some of the button presses.

Is there some implicit timing built into TIRTOS or the driver?  I need t be able to trust an interrupt to work every time or I will revert back to polling.

BillP

  • 0
    TI__Guru* 96960 points

    Hi Bill,

    The GPIO module driver and the interrupt example does not do any de-bounce management. Is the interrupt not running or are you seeing a de-bounce issue?

    Which version of TI-RTOS do you have. TI-RTOS 1.10.00.23 requires CCS 5.4 and no longer supports the LM3 parts. 1.01.00.25 requires CCS 5.3 and has support for the LM3 parts.

    Todd

  • 0 in reply to ToddMullanix
    Intellectual 585 points

    Hi Todd,

    I am using TI-RTS 1.01.00.25 and CCS v5.3, so the LM3 part should be OK (and it seems to be).

    Debounce sounds like the problem.  Is there a built-in way to deal with this or do I have to add my own debounce logic?  If so, are there examples for a button similar to what is on the LM3S9B96 board?  Thanks.

    BillP

  • 0 in reply to BillP
    TI__Guru* 96960 points

    We do not have any de-bounce management example code in TI-RTOS. You can take a look in the buttons.c file in StellarisWare.

    Todd

  • 0 in reply to ToddMullanix
    Intellectual 585 points

    Todd,

    Thank you for answering the original question.  I have not had time to thoroughly review the buttons.c code for debounce, but at first glance, it appears the debounce logic is included in the hwi code.  Doesn't debounce take milliseconds to stabilize?  If so, shouldn't the logic be pushed off to a lower priority task (using TI-RTOS)? 

    Bill

  • 0 in reply to BillP
    TI__Guru* 96960 points

    Which code are you referring to? Can you attach the file and denote which lines you are talking about.

    Thanks,

    Todd

  • 0 in reply to BillP
    Expert 1305 points

    Hi Bill,

    I am a new user of TI-RTOS. I am currently trying this example. After loading and runing the program, I cannot find any user button to toggle the led. Can you please advise where can I find a button to achieve this task?

    Thanks in advance!

    Bin

  • 0 in reply to Bin Li1
    Intellectual 585 points

    Hi Bin,

    I am using the LM3S9B96 development kit.  The user switch and LED are clearly marked on the board.  You must be using a different kit.

    This example shows how to connect a GPIO pin to a hardware interrupt.  It is not a good example for actually monitoring the state of a switch due to the debounce problems.  I found a simple solution which I will post when I have time.

    Bill

  • 0 in reply to BillP
    Expert 1305 points

    Hi Bill,

    Thanks for this, yes, I am using concerto board F28M35H52C1. So I do not have any button on the board. Thanks for letting me know that.

    Regards,

    Bin

  • 0 in reply to Bin Li1
    Intellectual 280 points

    Hello,

    I am also using Concerto Experimental Kit for F28M35H52C1. So, for GPIO interrupt example. I can not use user switch as its not provided on board.

    I plan to make one GPIO as Digital INput and do some soldering stuff around the kit bread board to add a user switch. Is this possible? If possible Can I have the circuit diagram of this kit?

    Thanks,

    Priyank Soni

  • 0 in reply to Priyank Soni
    Expert 1305 points

    Hi Priyank,

    I think that would be ok. Please check the link below which may be helpful.

    http://e2e.ti.com/support/embedded/bios/f/355/p/284610/993355.aspx#993355

    Regards,

    Bin