[参考译文] TM4C1294NCPDT：以太网固件更新

Unknown 说：

我尝试构建 MQTT 客户端时尝试了将其刻录到 Usig 引导加载程序从地址0x4000

这是哪个引导加载程序？ 这是基于闪存的 引导加载程序吗？ 如果您使用基于闪存的引导加载程序、那么如果 APP_START_ADDRESS 是 bl_config.h 文件中定义的0x4000、它会将您的固件编程为0x4000。  请参阅下面的片段。

//*****************************************************************************
//
// The starting address of the application. This must be a multiple of 1024
// bytes (making it aligned to a page boundary). A vector table is expected at
// this location, and the perceived validity of the vector table (stack located
// in SRAM, reset vector located in flash) is used as an indication of the
// validity of the application image.
//
// The flash image of the boot loader must not be larger than this value.
//
// Depends on: None
// Exclusive of: None
// Requires: None
//
//*****************************************************************************
#define APP_START_ADDRESS 0x00004000

//*****************************************************************************
//
// The address at which the application locates its exception vector table.
// This must be a multiple of 1024 bytes (making it aligned to a page
// boundary). Typically, an application will start with its vector table and
// this value should be set to APP_START_ADDRESS. This option is provided to
// cater for applications which run from external memory which may not be
// accessible by the NVIC (the vector table offset register is only 30 bits
// long).
//
// Depends on: None
// Exclusive of: None
// Requires: None
//
//*****************************************************************************
#define VTABLE_START_ADDRESS 0x00004000

//*****************************************************************************
//
// The size of a single, erasable page in the flash. This must be a power
// of 2.
//
// Depends on: None
// Exclusive of: None
// Requires: None
//
//*****************************************************************************
#define FLASH_PAGE_SIZE 0x4000

Unknown 说：

然后我添加了软件更新、它将控制权交给引导加载程序来烧录更新的固件、但它烧录的代码始于地址0x000

从应用程序跳转到引导加载程序与启动引导加载程序首次下载固件没有什么不同。  除非您调用 ROM 引导加载程序而不是闪存引导加载程序、否则它应更新0x4000处的固件。  在应用程序中调用它时、请参见下面的 SoftwareUpdateBegin。 基于 ROM 的引导加载程序将始终在0x0处对固件进行编程。  

//*****************************************************************************
void
SoftwareUpdateBegin(uint32_t ui32SysClock)
{
//
// Disable all processor interrupts. Instead of disabling them
// one at a time (and possibly missing an interrupt if new sources
// are added), 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;

//
// Also disable the SysTick interrupt.
//
SysTickIntDisable();
SysTickDisable();

//
// Return control to the boot loader. This is a call to the SVC
// handler in the flashed-based boot loader, or to the ROM if configured.
//
#if ((defined ROM_UpdateEMAC) && !(defined USE_FLASH_BOOT_LOADER))
ROM_UpdateEMAC(ui32SysClock);
#else
(*((void (*)(void))(*(uint32_t *)0x2c)))();
#endif
}