int main(void){
GPIO_InitTypeDef GPIO_InitDef;
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
GPIO_InitDef.GPIO_Pin = GPIO_Pin_13;
GPIO_InitDef.GPIO_Mode = GPIO_Mode_IN;
GPIO_InitDef.GPIO_OType = GPIO_OType_PP;
GPIO_InitDef.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_InitDef.GPIO_Speed = GPIO_Speed_2MHz;
GPIO_Init(GPIOA, &GPIO_InitDef);
uint32_t pin = !GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_13);
GPIO_InitDef.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitDef);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, DISABLE);
void (*SysMemBootJump)(void);
if ( (*((unsigned long *)0x2001C000) == 0xDEADBEEF) || pin || !app_ok()) {//Memory map, datasheet
*((unsigned long *)0x2001C000) = 0xCAFEFEED; //Reset bootloader trigger
__set_MSP(0x20001000);
//Point the PC to the System Memory reset vector (+4)
//AN2606
//Table 64. Bootloader device-dependent parameters
SysMemBootJump = (void (*)(void)) (*((uint32_t *) 0x1FFF0004));
SysMemBootJump();
while (1);
}else{
uint32_t stack = ((const uint32_t *)APP_START)[0];
uint32_t entry = ((const uint32_t *)APP_START)[1];
asm volatile(
"msr msp, %0 \n\t"
"bx %1 \n\t"
: : "r" (stack), "r" (entry)
);
while(1);
}
}
void checkForBootLoaderRequest(void)
{
uint32_t bt;
__PWR_CLK_ENABLE();
__BKPSRAM_CLK_ENABLE();
HAL_PWR_EnableBkUpAccess();
bt = (*(__IO uint32_t *) (BKPSRAM_BASE + 4)) ;
if ( bt == 0xDEADBEEF ) {
(*(__IO uint32_t *) (BKPSRAM_BASE + 4)) = 0xCAFEFEED; // Reset our trigger
// Backup SRAM is write-back by default, ensure value actually reaches memory
// Another solution would be marking BKPSRAM as write-through in Memory Protection Unit settings
SCB_CleanDCache_by_Addr((uint32_t *) (BKPSRAM_BASE + 4), sizeof(uint32_t));
void (*SysMemBootJump)(void);
__SYSCFG_CLK_ENABLE();
SYSCFG->MEMRMP |= SYSCFG_MEM_BOOT_ADD0 ;
uint32_t p = (*((uint32_t *) 0x1ff00000));
__set_MSP(p); //Set the main stack pointer to its defualt values
SysMemBootJump = (void (*)(void)) (*((uint32_t *) 0x1ff00004)); // Point the PC to the System Memory reset vector (+4)
SysMemBootJump();
while (1);
}
}
