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RTOS/TM4C1294NCPDT: Do TI RTOS use ROM API routines

Part Number: TM4C1294NCPDT

Tool/software: TI-RTOS

Hi,

I have a question regarding Ti RTOS.

From the training videos and literature of TI RTOS, i understand the RTOS uses TivaWare APIs underlying RTOS API.

Do RTOS uses APIs that are already available on ROM or it does call from driverlib (and burn them on Flash)? If not using those from ROM, is there a way in app.cfg to enable using them from ROM?

Thanks for reply,

Pranav.

  • Hi,

                 I have called ROM_updateUART(); in TI-RTOS application. It did not require any changes in .cfg file. So i guess other ROM functions also work in TI-RTOS environment .

    Regards,

    Digvijay

  • Dear Digvijay,

    I do understand that we can call ROM APIs in SYS/BIOS environment. That is very lucid.

    However, my question was regarding API call to Tivaware that is being made by SYS/BIOS API call. I will try to make it more clear:

    When we use any API of RTOS, some of those API calls Tivaware APIs to implement themselves. User is abstracted from this. User do not know what Tivaware APIs being called by RTOS API he is using.
    My question was that by default, the Tivaware API being called by RTOS ; is from ROM or being called from driverlib. If not from ROM by default, can we change this.


    BR,
    Pranav.
  • Hi Pranav,

    I will have to pass this to the TI-RTOS team for full confirmation, but my understanding is that they typically have leveraged MAP_ calls which are superior to ROM_ calls. The reason that using MAP_ calls is better, is that when calling with MAP_ it checks for whether a ROM API has been updated before calling it. Therefore, ROM_ API's will be called in most cases except for the handful of API's that had updates and/or bug fixes that are not included in the ROM'd TivaWare within the devices.
  • Hi Ralph,

    Thanks for your reply.

    However, i await your confirmation on this once you receive it from TI-RTOS team. 

    I also would appreciate you pointing me toward some literature that helps me understand this in more details.

    Thanks and Regards,

    Pranav. 

  • Pranav,

    The TI-RTOS drivers do not use the MAP_ calls. We did not want to supply multiple libraries (e.g. ones built with the ROM calls and another built with the flash ones). Additionally, we did not feel comfortable using the MAP_ calls without having the drivers go through our entire testing procedure with using the ROM APIs. Note, this was a simple matter of prioritizing resources.

    We provide source to the drivers, so you are always free to modify them if this is a requirement.

    Todd
  • Dear Todd,

    I am not sure if i understood your reply correctly.

    I understood that by default, RTOS do not uses ROM Tivaware. If it is like that, can we change this ? (to have a reduced footprint).



    BR,
    Pranav.
  • You have to change the TI-RTOS driver source code yourself if you want to use the ROM calls. The license is BSD, so you are free to make modifications.
  • Thanks for clarification.
    However, i feel its very difficult for user like me to search for relevant places in source code and edit it to have ROM calls.