In stm32u5xx_hal_flash_ex.c, version 1.6.2, FLASH_OB_GetUser() is defined as:
/**
* @brief Return the FLASH User Option Byte value.
* @retval The FLASH User Option Bytes values.
* The return value can be a combination of @ref FLASH_OB_USER_BOR_LEVEL,
* @ref FLASH_OB_USER_nRST_STOP, @ref FLASH_OB_USER_nRST_STANDBY,
* @ref FLASH_OB_USER_nRST_SHUTDOWN, @ref FLASH_OB_USER_SRAM_RST,
* @ref FLASH_OB_USER_IWDG_SW, @ref FLASH_OB_USER_IWDG_STOP,
* @ref FLASH_OB_USER_IWDG_STANDBY, @ref FLASH_OB_USER_WWDG_SW,
* @ref OB_USER_SWAP_BANK, @ref FLASH_OB_USER_DUALBANK,
* @ref FLASH_OB_USER_BKPRAM_RST, @ref FLASH_OB_USER_SRAM3_ECC,
* @ref FLASH_OB_USER_SRAM2_ECC, @ref FLASH_OB_USER_SRAM2_RST,
* @ref FLASH_OB_USER_nSWBOOT0, @ref FLASH_OB_USER_nBOOT0,
* @ref FLASH_OB_USER_PA15_PUPEN, @ref FLASH_OB_USER_IO_VDD_HSLV,
* @ref FLASH_OB_USER_IO_VDDIO2_HSLV and @ref OB_USER_TZEN
*/
static uint32_t FLASH_OB_GetUser(void)
{
uint32_t user_config = READ_REG(FLASH->OPTR);
CLEAR_BIT(user_config, FLASH_OPTR_RDP);
return user_config;
}
The reference to OB_USER_SWAP_BANK seems significant, since all the others are prefixed with FLASH_.
This turns out to be misleading, and unpacking the intent is confusing.
OB_USER_SWAP_BANK is 0x200, which does not correspond to a relevant bit in FLASH->OPTR. Like the other return values, I think this should be the defgroup FLASH_OB_USER_SWAP_BANK instead. The options in that group include OB_SWAP_BANK_ENABLE, defined as FLASH_OPTR_SWAP_BANK, which is indeed the SWAP_BANK bit (1<<20) in FLASH->OPTR.
As far as I can tell, OB_USER_SWAP_BANK should only be used as a UserType in FLASH_OB_UserConfig(). Which means the comments on that function, the FLASH_OBProgramInitTypeDef struct, and the FLASH_OB_USER_Type defgroup are all back to front as well. That means all the IS_OB_USER_* defines are misleadingly named as well. Correcting these to make a distinction between the FLASH_OB_USER_* defgroups, and the OB_USER_* UserTypes seems readily achievable and a big improvement in usability.
