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CCS/TM4C123GE6PM: Question on Boot Loader Demo 1

Richard Chen75
Intellectual 550 points

Part Number: TM4C123GE6PM

Tool/software: Code Composer Studio

Hello, I am new to TI so I apologize for any potential dump question here. I am currently confused on Boot Loader 1 demo project for this CPU. According to the document, this demo is an application used along with a flash-based boot loader,  which:

- Initializes/configures the peripheral used for downloading

- Branch back to the boot loader.

When I rebuit it and ran it over debugger, the code runs on Tiva C series dev board, however what I don't understand are:

1) Where is the flash based boot loader? The project doesn't appear to build the flash based boot loader at all, it only contains the application

2) Before I tested it, I have loaded Blinky sample project to the board, which gets loaded at the start of flash, since Boot Loader demo 1 application starts at 0x2800, how does this demo get run if there is no flash based boot loader written first to the start of the flash?

3) Once Boot Loader Demo 1 successfully runs, I restarted the board, then this application failed to load, which implies that there is NO flash based boot loader existed prior to the restart, so I am very confused that the document says that this project is related to the flash based boot loader, in addition, how does it work before restart like branching into boot loader? Does it use the boot loader from ROM if there is no flash based one?

Thanks

Richard

  • 0
    TI__Guru 72500 points
    If you are referring to the "boot_demo1" that is found in TivaWare "C:\ti\TivaWare_C_Series-2.1.4.178\examples\boards\dk-tm4c123g", this is just an application example starting at memory location 0x2800 that can call a flash bootloader which starts at address 0. There are two example flash based bootloaders in: "C:\ti\TivaWare_C_Series-2.1.4.178\examples\boards\dk-tm4c123g\boot_serial" and "C:\ti\TivaWare_C_Series-2.1.4.178\examples\boards\dk-tm4c123g\boot_usb".

    Here is another thread that gives some more details: e2e.ti.com/.../537529
  • 0 in reply to Bob Crosby
    Intellectual 550 points

    Thank you Bob for the reply. I took a look at the the thread e2e.ti.com/.../537529, and understand better now on how the program should be tested, however I still don't understand which boot loader was  called by boot loader demo 1 in my test case because I didn't download any flash based boot loader and the previous Blinky test has erased the flash region 0x0000.0000~0x0000.2800 because it got loaded to that region. I guess that the Boot Loader Demo 1 actually didn't successfully call into ANY flash boot loader, although the display prints a string saying so. Is it possible?

    Thanks

    Richard

  • 0 in reply to Richard Chen75
    Intellectual 550 points
    Bob, I followed the information in thread e2e.ti.com/.../537529, by downloading the boot loader first then Boot Loader Demo 1 later, now disconnecting the power and reconnecting it still makes Boot Loader Demo 1 run as expected, therefore my suspicion may be correct that there was no flash based boot loader running when I tested Boot Loader Demo 1 yesterday.

    Anyway, I think that I am good at right now, thanks again for the information and help!

    Richard