Where Vector Table resides in STMF0 devies

[Radoslav Mar]

Posted on June 26, 2018 at 14:03

I am asking this because when referring to the Reference Manual I see that the vector table resides at addresses 0x0000 0000 to 0x0000 00BC:

and the end of the table:

But if I go the the linker script file I see that the vector table is actually located at the flash memory section:

/* Specify the memory areas */

MEMORY

{

RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 4K

FLASH (rx) : ORIGIN = 0x8000000, LENGTH = 32K

}

/* Define output sections */

SECTIONS

{

/* The startup code goes first into FLASH */

.isr_vector :

{

. = ALIGN(4);

KEEP(*(.isr_vector)) /* Startup code */

. = ALIGN(4);

} >FLASH

........

........

What am I missing? The document says that it starts from address 0x0, while the Linker Script file says it starts at the first flash section address address.

[David SIORPAES]

Posted on June 26, 2018 at 14:09

In STM32F0 the flash is aliased to 0x0 if booting from flash.

[Tesla DeLorean]

Posted on June 26, 2018 at 14:18

The CM0 parts it is always at address zero, other hardware then allows for the mapping/shadowing of RAM, FLASH or ROM at that address.

To use an alternate table (ie IAP loader + application) you would reserved some space at the base of RAM, copy your table there, and then remap the RAM so it appears at both 0x20000000 and 0x00000000

For the CM0+ parts the VTOR is available and you can program in an aligned tabled, ie SCB->VTOR = 0x08004000

[Radoslav Mar]

Posted on June 27, 2018 at 14:09

What does aliased mean? The same physical memory accessed by two different code addresses?

And why is  it necessary at all?