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TM4C ROM Bootloader

Go Bravos
Expert 6090 points

Hi,

We're trying to figure out how to use the ROM boot loader to program new, blank Tiva chips. Does the ROM bootloader have an IO pin to control it when the processor is reset like the flash boot loader?

Thank you,

Brad

  • 0
    TI__Guru**** 192486 points

    Hello Brad,

    At reset, the user has the opportunity to direct the core to execute the ROM bootloader or the application in Flash memory by using the GPIO signal configured in BOOTCFG register. At reset, the following sequence is performed:

    1.The BOOTCFG register is read. If the EN bit is clear, the ROM Boot Loader is executed.
    2.In the ROM Boot Loader, the status of the specified GPIO pin is compared with the specified polarity. If the status matches the specified polarity, the ROM is mapped to address 0x0000.0000 and execution continues out of the ROM Boot Loader.
    3.If the EN bit is set or the status doesn't match the specified polarity, the data at address 0x0000.0004 is read, and if the data at this address is 0xFFFF.FFFF, the ROM is mapped to address 0x0000.0000 and execution continues out of the ROM Boot Loader.
    4.If there is data at address 0x0000.0004 that is not 0xFFFF.FFFF, the stack pointer is loaded from Flash memory at address 0x0000.0000 and the program counter is loaded from address 0x0000.0004. The user application begins executing.

    Regards,

    QJ