STM32L471 System Memory always mapped to 0x0000_0000?

[Pieter Conradie]

Hi everyone!

I have found that the System Memory (Boot ROM) is always mapped to 0x0000_0000 on the STM32L471RET6 that I'm developing on. The Flash Memory is mapped to 0x0800_0000 as expected but as soon as interrupts are triggered they jump to 0x1FFFF_xxxx.

To prevent this SCB_VTOR must be set to 0x0800_0000 by defining USER_VECT_TAB_ADDRESS so that code in system_stm32l4xx.c:SystemInit() is compiled in.

As far as I can tell there are two settings in the Reference Manual that can affect this. The BFB2 bit in User Options and the SYSCFG_MEMRMP:MEM_MODE[2:0] register.

I have checked and SYSCFG_MEMRMP = 0x0000_0000 and @0x1FFFF_7800 = 0xFF

EF_F8AA and FLASH_OPTR = 0xFFEF_F8AA so no surprises there.

Can anyone confirm that this is indeed a bug? Did I miss something?

Thanks in advance,

Pieter

https://piconomix.com

P.S. I checked and the STM32L476 on the NUCLEO-L476RG does not exhibit this problem.

[KnarfB · Accepted solution]

Is the BOOT0 pin low?

[Pieter Conradie]

Sorry, forgot to add that detail: yes, the BOOT0 pin is low.

[Pieter Conradie]

Oh wait! Somewhere I must have lost the plot :pensive_face: Thanks @KnarfB​ ! I checked again and there was the jumper indeed, pulling BOOT0 high. There must have been a mix up somewhere during the investigation and it's hard to spot (black on black). I've removed the offending jumper and now the memory map is OK.

Apologies!

Pieter