Flash Protect Set FSEC 0xBF

[yuanzhiwen]

In the BootLoader, we set FSEC to 0xBF to enable Flash protection and implemented an unlock mechanism in the BootLoader, allowing temporary unlocking via password input. Currently, we can unlock by sending a key over CAN, which works successfully: in IAR, setting the reset method to "Core" allows erasing/programming the S32K144 via debug mode. However, when attempting to use JFlash for software flashing, it fails. The issue is that the "connect" operation in JFlash resets the chip, reactivating Flash protection and disabling the SWD interface. How can we resolve this to enable flashing via JFlash? Your guidance is appreciated. Thank you.

[VaneB]

Hi @yuanzhiwen 

To avoid locking the MCU again, make sure the J-Link does not reset the device when connecting. Instead, you will need to use a special J-Link script that allows you to attach without triggering a reset. You can find the script and instructions here: SEGGER Wiki – S32Kxxx Attach to Debug Session

To run it, just launch J-Link Commander like this:

C:\Programme\SEGGER\JLink\JLink.exe -JLinkScriptFile NXP_Kinetis_S32_Attach.JLinkScript

This way, the MCU stays running and you’ll have full access to memory and registers.

If you run into any issues or need more help, please contact SEGGER support.

BR, VaneB