STM32L072CZ - Jumping in DFU bootloader via software

[andre239955_stm1_stmicro]

Hello

I'm migrating my STM32F072 project to the STM32L072.

In my original project (F072) I can jump to the DFU bootloader by software via a function located before SystemInit.

I tried to convert this to be used by L072 by changing the address of bootloader program to 0x1ff00004 it's not working.

Is it due to the dual memory bank? Is there a way to get it working?

Thank-you

André

[Uwe Bonnes]

I.m.h.o., best way to do so is to set some marker in on-chip ram, trigger reset and early in startup code test for that pattern in RAM and if found, reset it. set up VTOR etc for system bootloader and jump to system bootloader.

[andre239955_stm1_stmicro]

void (*SysMemBootJump)(void);
 
#define SRAM_ADDRESS_DFU			(unsigned long *)0x20004FF0	// *((unsigned long *)0x20004FF0) 20kRam
 
void SystemInit (void)
{
		 if ( *((unsigned long *)SRAM_ADDRESS_DFU) == 0xDEADBEEF ) {
	 *((unsigned long *)SRAM_ADDRESS_DFU) = 0xCAFEFEED; // Reset our trigger
	 __set_MSP(0x20002250);
	 // 0x1ff0 0000 is "System Memory" start address for STM32 L0xx
	 SysMemBootJump = (void (*)(void)) (*((uint32_t *) 0x1ff00004)); // Point the PC to the System Memory reset vector (+4)
	 SysMemBootJump();
	 while (1);
	 }
....

Hi,

It's exactly what I do, working perfectly with F072, not working with L072

[TDK]

This thread claims the BOOT0 pin is sampled in the bootloader, but I'm a bit skeptical. The other comments should help you:

https://community.arm.com/developer/tools-software/tools/f/keil-forum/41955/stm32l072-jumping-to-embedded-bootloader-from-application-code

[Uwe Bonnes]

You have to set  SYSCFG->CFGR1 so that system rom gets mapped at address 0 before the jump

[andre239955_stm1_stmicro]

Hi thank-you for feedback,

I added

	 SysMemBootJump = (void (*)(void)) (*((uint32_t *) 0x1ff00004)); // Point the PC to the System Memory reset vector (+4)
	 SYSCFG->CFGR1 |= 0x01 ;
	 SysMemBootJump();

Maybe I didn't correctly understand you, but the system reset immediately and didn't jump in the DFU mode

[Uwe Bonnes]

STM32L0 also has VTOR, so you may need to set it too.

[andre239955_stm1_stmicro]

Not better :(

[MM..1]

Jump on MCUs with detection firmware in flash not work or better say work , but default jump back to app if is detected in flash. One way is erase first memory sector before jump.

Second maybe as AN2606 pattern say 

try BFB2 0

[Uwe Bonnes]

Then single step in the debugger and find out where and why things go wrong.

[ulysse]

Hi, I'm facing the same issue on my L072.

Have you finally succeeded to get into DFU ? If so, can you tell me how ?

[teru839]

This is my code, it worked fine on my L072.

It is imporant to erase the first 4 bytes of user flash, you can find in AN2606 Rev 64 (p.69).

I was helped by many posts, thanks all.

 

#define BOOTLOADER_MAGIC_ADDR 		 ((uint32_t*) ((uint32_t) 0x2000142c)) // ._user_heap_stack front addr
#define BOOTLOADER_MAGIC_TOKEN 		 0xDEADBEEF
#define BOOTLOADER_START_ADDR 		 0x1FF00000

// call this at any time to initiate a reboot into bootloader
void RebootToBootloader(){
 *BOOTLOADER_MAGIC_ADDR = BOOTLOADER_MAGIC_TOKEN;
 NVIC_SystemReset();
}

// call this in first line of main()
void bootloaderSwitcher(){
 uint32_t jumpaddr;
 FLASH_EraseInitTypeDef erase;
 uint32_t pageError = 0;

 if (*BOOTLOADER_MAGIC_ADDR == BOOTLOADER_MAGIC_TOKEN){
 *BOOTLOADER_MAGIC_ADDR = 0;

 // Avoid the empty check mechanism
 erase.TypeErase = FLASH_TYPEERASE_PAGES;
 erase.PageAddress = 0x08000000;
 erase.NbPages = 1;
 HAL_FLASH_Unlock();
 HAL_FLASHEx_Erase(&erase, &pageError);
 HAL_FLASH_Lock();

 void (*bootloader)(void) = 0;
 jumpaddr = *(__IO uint32_t*)(BOOTLOADER_START_ADDR + 4);
 bootloader = (void (*)(void)) jumpaddr;
 __set_MSP(*(__IO uint32_t*) BOOTLOADER_START_ADDR); 
 bootloader();
 while(1){}
 }
}