[参考译文] IWRL6432：IWRL 6432 - APP 到 SBL 开关

https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/1359556/iwrl6432-iwrl-6432---app-to-sbl-switch

您好！

我们想知道如何在通过看门狗计时器完成热复位后再次从应用切换回 SBL (次级引导加载程序)。 为方便您参考、我们将使用我们的 SBL 所在的此位置#define SBL_vector ((uint32_t) 0xE000ED08)。 因此我们的假设是、一旦热复位完成、它将转到这个指定的 SBL 位置并触发 SBL。  但这种功能不会发生、因此我们想知道如何实现这一点、以及需要进行哪些更改。
如果需要,我们可以提供更多信息。

注意：我们正在使用 SDK 05_04_00_01版本，TI 提供了一个热复位的示例代码，称为看门狗复位。 我们已经将此示例代码与示例 hello world 代码合并、并在此处附上了相应的代码更改以供您参考。

谢谢

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#include <stdio.h>
#include <kernel/dpl/DebugP.h>
#include <kernel/dpl/ClockP.h>
#include <kernel/dpl/HwiP.h>
#include <drivers/watchdog.h>
#include "ti_drivers_config.h"
#include "ti_drivers_open_close.h"
#include "ti_board_open_close.h"
//#include "transport.h"
//#define SBL_VECTOR  ((uint32_t) 0xE000ED08)
#define SBL_VECTOR 0x00458000
volatile uint32_t *vtor;

#define NUM_OF_ITERATIONS    (3U)
void app_switchtoSBL();
void app_switchtoSBL()
{   DebugP_log("Switching to SBL");

      *vtor = SBL_VECTOR;


#if (!UNIT_TEST)
    __asm(" MSR MSP, %0" : :"r" ((uint32_t)*vtor));
    //__asm("BX %0"::"r" ((uint32_t)*(vtor)));
    __asm("BX %0"::"r" ((uint32_t)*(vtor+4)));
#endif


}
void hello_world_main(void *args)
{
    /* Watchdog timer expiry time in millisecond */
    uint32_t wdtExpiryTimeinMs = gWatchdogParams[CONFIG_WDT0].expirationTime;
    uint32_t index = 0;
    /* Open drivers to open the UART driver for console */
    Drivers_open();
    Board_driversOpen();
    DebugP_log("Hello World!\r\n");
    Watchdog_enable(gWatchdogHandle[CONFIG_WDT0]);

    
    DebugP_log("Watchdog reset Mode Test Started ...\r\n");

    DebugP_log("Servicing WDT for few iterations \r\n");

    /* Service the WDT for more than expiry time */
    for(index = 0; index < NUM_OF_ITERATIONS; index++)
    {
        /* Need to service the WDT in open window */
        while(Watchdog_isClosedWindow(gWatchdogHandle[CONFIG_WDT0]) == true);
        /* Clear Watchdog timer */
        Watchdog_clear(gWatchdogHandle[CONFIG_WDT0]);
        /* wait for (expiry time/2 ) time */
        ClockP_usleep((wdtExpiryTimeinMs*100)/2);
    }
    DebugP_log("Watchdog triggers warm reset in %d (ms)\r\n", wdtExpiryTimeinMs);
    DebugP_log("All tests have passed!!\r\n");

    /* Wait till WDT triggers the reset */
    while(1)
    {
        DebugP_log("Prints will be stopped after reset mcw \r\n");
    }
    app_switchtoSBL();
    DebugP_log("stopped watchdog!!\r\n");
    // Board_driversClose();
    // Drivers_close();
}