2 Replies Latest reply on Nov 6, 2017 7:26 PM by user_474925260

    Sharing const variable between BLE Stack and Application in OTA Updatable Stack scenario

    user_474925260

      Hello, I have implemented the updatable stack OTA (over the air) scenario. 

       

      I would now like to put the STACK build date time (__DATE__ and __TIME__) into a global / const area of the stack application and be able to access it from my user APPLICATION code.  I would like this so I can query the build date/time of both stack and application from my phone and decide if an update for either is needed.

       

      I would imagine there is a way to share variables across the stack / application since the entire stack is shared across that boundary (and the linker script must be handling that)....?

       

      Is there documentation on how to define something in the stack that will be 'exported' and how to then 'import' it by the application?  I had previously seen something about pragmas and sections that might be what I need but didn't bookmark it and can't find it now...

       

      Any help is appreciated including just pointing me at a link...

       

      Thanks!

       

      -Kevin

        • 1. Re: Sharing const variable between BLE Stack and Application in OTA Updatable Stack scenario
          user_474925260

          I am still interested in the answer to this (sharing const data from the stack to the application) but for now am instead just trying to have the Stack save the data to the User Flash space with CyBle_StoreAppData.  I'm about to post another question about that...

           

          Thanks!

          • 2. Re: Sharing const variable between BLE Stack and Application in OTA Updatable Stack scenario
            user_474925260

            I was interested in having one place to store the build date/time for each part of the OTA launcher/stack/app.  By putting it in the launcher flash area, I wouldn't have to worry about it moving around since that remains static (is never updated vs the stack and app)...

             

            Ultimately, I did the following.... 

             

            1- create const variables in the Launcher app:

            const char launcherDT[24] CY_SECTION(".DATA") = __DATE__ " " __TIME__;

            const char stackDT[24] CY_SECTION(".DATA") = "N/A";

            const char appDT[24] CY_SECTION(".DATA") = "N/A";

             

            2- access them in a simple fashion in the launcher (or the optimizer removed them!)

                char msgBuff[24];

                strcat(msgBuff, launcherDT);

                strcat(msgBuff, stackDT);

                strcat(msgBuff, appDT);

             

            3- look at the generated map file to find the memory location they were going to be put at:

            .DATA          0x00000ab8       0x48 .\CortexM0\ARM_GCC_541\Debug\main.o

                            0x00000ab8                launcherDT

                            0x00000ad0                stackDT

                            0x00000ae8                appDT

            4- use those memory locations later in STACK and APP to write to the locations:

                // these are the locations in the Launcher part of the flash

            const char *launcherDT = (char *)0x00000ab8;

            const char *stackDT = (char *)0x00000ad0;

            const char *appDT = (char *)0x00000ae8;

             

                // keep this for us to put stackDT above

            const char *buildDT = __DATE__ " " __TIME__;

             

            CyBle_StoreAppData((uint8 *)(buildDT), (const uint8 *)(stackDT), 20, 1);

             

            5- read from those locations

             

            UART_UartPutString(launcherDT);

            UART_UartPutString("\r\n");