Title shortened from:
"With the STM32U545RE, unable to erase the correct Flash Bank, using HAL_FLASHEx_Erase(), when attempting to switch from Bank2 to Bank1".
Testing is done with the Nulceo-U545RE-Q board having 512KB Flash organized in two Banks. Each Bank has 32 pages of 8KB each. Flash Bank1: 0-31 pages. Flash Bank2: 32-63 pages.
I could switch-over from Firmware-Version1 executing in Bank1 to Firmware-Version2 executing in Bank2.
I verified that Firmware-Version2 was executing correctly even after hardware reset and power cycle.
Attempting to switch-over from Firmware-Version2 executing in Bank2 to Firmware-Version3 executing in Bank1 fails as I end up erasing the Bank with the currently executing software(Firmware-Version2).
I checked the setting of the SWAP_BANK bit and then erased the Bank, using the code below:
/* Get the boot configuration status */
HAL_FLASHEx_OBGetConfig(&OBInit);
/* Check Swap Flash banks status */
if ((OBInit.USERConfig & OB_SWAP_BANK_ENABLE) == OB_SWAP_BANK_DISABLE)
{
BankNumber=FLASH_BANK_2; // bank for erase
}
else
{
BankNumber=FLASH_BANK_1; // bank for erase
}
FirstPage=0;
NbOfPages=32;
/* Fill EraseInit structure*/
EraseInitStruct.TypeErase = FLASH_TYPEERASE_PAGES;
EraseInitStruct.Banks = BankNumber;
EraseInitStruct.Page = FirstPage;
EraseInitStruct.NbPages = NbOfPages;
if (HAL_FLASHEx_Erase(&EraseInitStruct, &PageError) != HAL_OK)
{
FotaErrorOnErase=1;
}
Program execution halts immediately.
Using CUBEPROGRAMMER, I verified that the SWAP_BANK bit is set (checked).
Using CUBEPROGRAMMER, I noticed that Bank1 has been Erased! This had Firmware-Version2.
Now assuming that with the SWAP_BANK bit as set, Bank2 with Firmware_Version2 is now mapped as Bank1. And so Bank1 with Firmware_Version1 is now mapped as Bank2.
And so I implied that maybe I must always erase Bank2. So I modified the code as below:
BankNumber=FLASH_BANK_2;
FirstPage=0;
NbOfPages=32;
/* Fill EraseInit structure*/
EraseInitStruct.TypeErase = FLASH_TYPEERASE_PAGES;
EraseInitStruct.Banks = BankNumber;
EraseInitStruct.Page = FirstPage;
EraseInitStruct.NbPages = NbOfPages;
if (HAL_FLASHEx_Erase(&EraseInitStruct, &PageError) != HAL_OK)
{
FotaErrorOnErase=1;
}
But this does not work either and checking in CUBEPROGRAMMER, I noticed that Bank1 has been erased again! This had the currently executing code (Firmware-Version2 as the SWAP_BANK bit is checked)
I disabled the Erase Logic and calls to HAL_FLASHEx_Erase() in the code and manually erased
BANK2 using the CUBEPROGRAMMER and I could do Firmware updates as per the sequence below.
1. Using CUBEPROGRAMMER - Manually did "Full Chip Erase" and set the SWAP_BANK bit to cleared(unchecked) and using CUBEIDE, downloaded Firmware-Version1 to Bank1
2. Firmware-Version1 executing in Bank1 loads Firmware-Version2 to Bank2
3. Using CUBEPROGRAMMER, manually "Erase Selected Sectors": 32-63
4. Firmware-Version2 executing in Bank2 loads Firmware-Version3 to Bank1
5. Using CUBEPROGRAMMER manually "Erase Selected Sectors": 32-63
6. Firmware-Version3 executing in Bank1 loads Firmware-Version4 to Bank2
So I conclude that I am not correctly using the HAL_FLASHEx_Erase() function.
I request ST for proper documentation and examples for the STM32U545RE - explaining the correct use of the HAL_FLASHEx_Erase() function when executing from Bank2 and attempting to erase Bank1 (ie with the SWAP_BANK bit set)
