text: //*****************************************************************************
  //
  // boot_demo_uart.c - UART boot loader example.
  //
  // Copyright (c) 2013-2015 Texas Instruments Incorporated.  All rights reserved.
  // Software License Agreement
  //
  // Texas Instruments (TI) is supplying this software for use solely and
  // exclusively on TI's microcontroller products. The software is owned by
  // TI and/or its suppliers, and is protected under applicable copyright
  // laws. You may not combine this software with "viral" open-source
  // software in order to form a larger program.
  //
  // THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS.
  // NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT
  // NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY
  // CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
  // DAMAGES, FOR ANY REASON WHATSOEVER.
  //
  // This is part of revision 2.1.2.111 of the DK-TM4C129X Firmware Package.
  //
  //*****************************************************************************
  
  #include <stdbool.h>
  #include <stdint.h>
  #include "inc/hw_memmap.h"
  #include "inc/hw_nvic.h"
  #include "inc/hw_types.h"
  #include "driverlib/rom.h"
  #include "driverlib/rom_map.h"
  #include "driverlib/sysctl.h"
  #include "driverlib/uart.h"
  #include "grlib/grlib.h"
  #include "grlib/widget.h"
  #include "drivers/frame.h"
  #include "drivers/kentec320x240x16_ssd2119.h"
  #include "drivers/pinout.h"
  #include "drivers/touch.h"
  
  //*****************************************************************************
  //
  //! \addtogroup example_list
  //! <h1>Boot Loader UART Demo (boot_demo_uart)</h1>
  //!
  //! This example demonstrates the use of the ROM-based UART boot loader.  When
  //! the application runs, it will wait for the screen to be pressed (to
  //! simulate an application waiting for a trigger to begin a firmware update)
  //! and then branch to the UART boot loader in the ROM.  The UART is configured
  //! for a baud rate of 115,200 and does not require the use of auto-bauding.
  //
  //*****************************************************************************
  
  //*****************************************************************************
  //
  // A global we use to keep track of when the user presses the screen.
  //
  //*****************************************************************************
  volatile bool g_bFirmwareUpdate = false;
  
  //*****************************************************************************
  //
  // The error routine that is called if the driver library encounters an error.
  //
  //*****************************************************************************
  #ifdef DEBUG
  void
  __error__(char *pcFilename, unsigned long ulLine)
  {
  }
  #endif
  
  //*****************************************************************************
  //
  // This function is called in interrupt context by the touch screen driver when
  // there is a pointer event.
  //
  //*****************************************************************************
  int32_t
  TSHandler(uint32_t ui32Message, int32_t i32X, int32_t i32Y)
  {
      //
      // See if this is a pointer up message.
      //
      if(ui32Message == WIDGET_MSG_PTR_UP) {
          //
          // The screen has been pressed and released, so begin the firmware
          // update.
          //
          g_bFirmwareUpdate = true;
      }
  
      //
      // Success.
      //
      return(0);
  }
  
  //*****************************************************************************
  //
  // A simple application demonstrating use of the boot loader,
  //
  //*****************************************************************************
  int
  main(void)
  {
      uint32_t ui32SysClock;
      tContext sContext;
      tRectangle sRect;
  
      //
      // Run from the PLL at 120 MHz.
      //
      ui32SysClock = MAP_SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ |
                                             SYSCTL_OSC_MAIN | SYSCTL_USE_PLL |
                                             SYSCTL_CFG_VCO_480), 120000000);
  
      //
      // Configure the device pins.
      //
      PinoutSet();
  
      //
      // Initialize the display driver.
      //
      Kentec320x240x16_SSD2119Init(ui32SysClock);
  
      //
      // Initialize the graphics context.
      //
      GrContextInit(&sContext, &g_sKentec320x240x16_SSD2119);
  
      //
      // Draw the application frame.
      //
      FrameDraw(&sContext, "boot-demo-uart");
  
      //
      // Print instructions on the screen.
      //
      GrStringDrawCentered(&sContext, "Press the screen to start", -1, 160, 108,
                           false);
      GrStringDrawCentered(&sContext, "the update process", -1, 160, 128, false);
  
      //
      // Initialize the touch screen driver.
      //
      TouchScreenInit(ui32SysClock);
  
      //
      // Set the touch screen event handler.
      //
      TouchScreenCallbackSet(TSHandler);
  
      //
      // Enable the UART that will be used for the firmware update.
      //
      ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
  
      //
      // Configure the UART for 115200, 8-N-1.
      //
      ROM_UARTConfigSetExpClk(UART0_BASE, ui32SysClock, 115200,
                              (UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE |
                               UART_CONFIG_WLEN_8));
  
      //
      // Enable the UART operation.
      //
      ROM_UARTEnable(UART0_BASE);
  
      //
      // Wait until the screen has been pressed, indicating that the firwmare
      // update should begin.
      //
      while(!g_bFirmwareUpdate) {
      }
  
      //
      // Clear the screen.
      //
      sRect.i16XMin = 0;
      sRect.i16YMin = 0;
      sRect.i16XMax = 319;
      sRect.i16YMax = 239;
      GrContextForegroundSet(&sContext, ClrBlack);
      GrRectFill(&sContext, &sRect);
  
      //
      // Indicate that the firmware update is about to start.
      //
      GrContextForegroundSet(&sContext, ClrWhite);
      GrStringDrawCentered(&sContext, "Update process started...", -1, 160, 98,
                           false);
      GrStringDrawCentered(&sContext, "Using UART0 with", -1, 160, 138, false);
      GrStringDrawCentered(&sContext, "115,200 baud, 8-N-1.", -1, 160, 158,
                           false);
  
      //
      // Disable all processor interrupts.  Instead of disabling them one at a
      // time, a direct write to NVIC is done to disable all peripheral
      // interrupts.
      //
      HWREG(NVIC_DIS0) = 0xffffffff;
      HWREG(NVIC_DIS1) = 0xffffffff;
      HWREG(NVIC_DIS2) = 0xffffffff;
      HWREG(NVIC_DIS3) = 0xffffffff;
      HWREG(NVIC_DIS4) = 0xffffffff;
  
      //
      // Call the ROM UART boot loader.
      //
      ROM_UpdateUART();
  
      //
      // The boot loader should not return.  In the off chance that it does,
      // enter a dead loop.
      //
      while(1) {
      }
  }
  