[参考译文] TM4C129ENCPDT：为 EK-TM4C129EXL 创建定制引导加载程序

void MyInitFunc(void){


            volatile uint32_t ui32Loop;

           //
           // Enable the GPIO port that is used for the on-board LED.
           //
           ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPION);

           //
           // Check if the peripheral access is enabled.
           //
           while(!ROM_SysCtlPeripheralReady(SYSCTL_PERIPH_GPION))
           {
           }

           //
           // Enable the GPIO pin for the LED (PN0).  Set the direction as output, and
           // enable the GPIO pin for digital function.
           //
           ROM_GPIOPinTypeGPIOOutput(GPIO_PORTN_BASE, GPIO_PIN_0);

           //
           // Loop forever.
           //

           volatile  uint16_t xi;

           for( xi = 0; xi <100; xi++)
           {
               //
               // Turn on the LED.
               //
               ROM_GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_0, GPIO_PIN_0);

               //
               // Delay for a bit.
               //
               for(ui32Loop = 0; ui32Loop < 500000; ui32Loop++)
               {
               }

               //
               // Turn off the LED.
               //
               ROM_GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_0, 0x0);

               //
               // Delay for a bit.
               //
               for(ui32Loop = 0; ui32Loop < 500000; ui32Loop++)
               {
               }
        }

}

uint32_t DetermineBootSeq(void){

    uint32_t ui32EEPROMInit;
    uint32_t ReadCustomBLFlags[2];
    //
    // Enable the EEPROM module.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_EEPROM0);
    //
    // Wait for the EEPROM module to be ready.
    //
    while (!SysCtlPeripheralReady(SYSCTL_PERIPH_EEPROM0))
    {
    }
    //
    // Wait for the EEPROM Initialization to complete
    //
    ui32EEPROMInit = EEPROMInit();
    //
    // Check if the EEPROM Initialization returned an error
    // and inform the application
    //
    if (ui32EEPROMInit != EEPROM_INIT_OK)
    {
        while (1)
        {
        }
    }
    //  //Get the EEPROMSize +
    //READ some data FROM THE LAST 2 WORD OF the EEPROM
    //
    //uint32_t EepromMaxSize = EEPROMSizeGet();
    EEPROMRead(ReadCustomBLFlags, BL_CUSTOME_FLAGS_ADDRESS,
               sizeof(ReadCustomBLFlags));

    if (ReadCustomBLFlags[BL_ALWAYS_RUN_ADDRESS] == BL_ALWAYS_RUN)
    {
        return (1);
    }
    else
    {
        if (ReadCustomBLFlags[BL_UPDATE_STATUS_ADDRESS] == BL_UPDATE_END)
        {
            //
            // See if the first location is 0xfffffffff or something that does not
            // look like a stack pointer, or if the second location is 0xffffffff or
            // something that does not look like a reset vector.
            //
          volatile  uint32_t *pui32App;
            pui32App = (uint32_t*) APP_START_ADDRESS;
            if ((pui32App[0] == 0xffffffff)
                    || ((pui32App[0] & 0xfff00000) != 0x20000000)
                    || (pui32App[1] == 0xffffffff)
                    || ((pui32App[1] & 0xfff00001) != 0x00000001))
            {
                return (1);
            }
            //a valid image exists
            // and no update is needed.
            // return(0)
            return (0);
        }
        else
        {
                        //If the update not complated run the bootloader for update

            return (1);
        }
    }

}

void MyStartFunc(void){


            volatile uint32_t ui32Loop;

           //
           // Enable the GPIO port that is used for the on-board LED.
           //
           ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPION);

           //
           // Check if the peripheral access is enabled.
           //
           while(!ROM_SysCtlPeripheralReady(SYSCTL_PERIPH_GPION))
           {
           }

           //
           // Enable the GPIO pin for the LED (PN0).  Set the direction as output, and
           // enable the GPIO pin for digital function.
           //
           ROM_GPIOPinTypeGPIOOutput(GPIO_PORTN_BASE, GPIO_PIN_0);

           //
           // Loop forever.
           //

           volatile  uint32_t xi;

           for( xi = 0; xi <100; xi++)
           {
               //
               // Turn on the LED.
               //
               ROM_GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_0, GPIO_PIN_0);

               //
               // Delay for a bit.
               //
               for(ui32Loop = 0; ui32Loop < 500000; ui32Loop++)
               {
               }

               //
               // Turn off the LED.
               //
               ROM_GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_0, 0x0);

               //
               // Delay for a bit.
               //
               for(ui32Loop = 0; ui32Loop < 500000; ui32Loop++)
               {
               }
        }

}