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Gpeti
Senior
March 10, 2023
Solved

Value of register VTOR at reset on STM32H753

The value of register VTOR at reset is "unknown" in the STM32H753 Programming Manual.

I assume this is because it depends on the boot configuration of the product (boot pin and boot adress option byte) ?

Is it correct to say that in the default boot configuration the value of VTOR at reset is 0x0800 0000 ? (I don't have a board to test it in the following days)

Also, when the VTOR is modified by the software, does its value go back to default for any kind of reset ? (warm reset, power on, etc...)

This topic has been closed for replies.
Piranha
PiranhaBest answer
Principal III
March 13, 2023

The VTOR is initialized in the same manner on F7 series, which doesn't have the RSS feature. Most likely it's done by the same boot logic, which makes decisions based on BOOT0, option bytes, checks for empty flash on some series etc.

3 replies

Piranha
Principal III
March 12, 2023

RM0433 Rev 7:

  • 2.6 Boot configuration
  • Table 21. Option byte organization
  • 4.4.7 Description of boot address option bytes
  • 4.9.17 FLASH register boot address FLASH_BOOT_CURR)
  • 4.9.18 FLASH register boot address FLASH_BOOT_PRGR)

And, of course, the VTOR register gets back to one of those defaults on any kind of reset.

Pavel A.
March 13, 2023

From a short test on my Nucleo-H743, the reset value of VTOR is 0x080000000.

Not sure, however, is this the property of its CM7 core or effect of low-level ST firmware that decodes the option bytes and initializes the MCU (so called "Root Secure Service" or whatever).

Piranha
PiranhaBest answer
Principal III
March 13, 2023

The VTOR is initialized in the same manner on F7 series, which doesn't have the RSS feature. Most likely it's done by the same boot logic, which makes decisions based on BOOT0, option bytes, checks for empty flash on some series etc.