Does JTAG/SWD access locks Flash in RDP2 ?

[vsing.1]

Hi ,

I am working on STM32U575 nucleo board .

Flash got locked (code freeze) and i have to power cycle board to run my application in below cases :

1. Switching from RDP0 to RDP2 in firmware on Pushbutton operation . Application freeze . It runs again when i toggle IDD jumper.
2. When in RDP2 if i try to connect via SWD ,Application freeze .It runs again when i toggle IDD jumper .

I am using 5V_USC_C to provide power supply to board.

Is this behavior acceptable , as going through some reference i have read that in RDP1 access via JTAG is considered as Intrusion and it locks Flash.

Does it applies to RDP2 also ?

@TDK​  @JHOUD​ 

[Bob S]

I don't know specifically about the STM32U5 series, but in other series (F4, L4, G4, F7):

Item 2 - yes, in RDP1 *OR* RDP2, any attempt to connect via JTAG or SWD will halt the CPU.

Item 1 - Don't recall if this is normal (needing power cycle after firmware activates RDP2), but it wouldn't surprise me if that was the case.

[Bubbles]

Hi @vsing.1​ ,

first point - usually for the change in OB to become active the system needs to reload the OB. If you need power on reset to do OBL, then there is some problem in OBL_LAUNCH. But difficult to diagnose remotely, but check that.

second point - Bob answered correctly.

BR,

J