Hi teams,
CPU: STM32U0
Current RDP level: Level 1
OEM1 RDP lock: Enabled.
I had set the 128bit OEM1 key to the OEM key registers [FLASH_OEM1KEYWyR ]accordingly, and the written OEM1 key values was verified using their CRC values by reading OEM1KEYCRC register.
Now I am trying to make the regression from level 1 to level 0 according to the user manual description [section: 3.5.1 FLASH read protection (RDP)].
But the operation was failed using my source code. Which is attached below
#define STM32U0_DBGMCU_BASE 0x40015800 // Accessible to the software via the APB access port AP0
#define STM32U0_DBGMCU_DBG_AUTH_HOST (STM32U0_DBGMCU_BASE + 0x100) // Debug authentication mailbox host register
Could you please clarify the following doubts,
1. The unlock sequence says, debug access port 1 has to be used for programming the 128-bit OEM1 key in the DBGMCU_DBG_AUTH_HOST register,
but when I checked the DBGMCU_DBG_AUTH_HOST register base, it says
So, what is the base address for DBGMCU_DBG_AUTH_HOST register and which AP should be selected during OEM key write process.
2. After connecting the target from the following settings via STM32 Cube programmer. I have tried to change RDP level using secure programming page.
What could be the reason behind this?
3. If I select the AP to 1, target connection is not feasible and the following error prompt was occurred.
Right now the flash memory is not accessible, please let me know how can I recover from this issue.
Thanks
Akhil
