2420013_en-US

S32K3 HSE AB Swap: 10s cyclic HSE-SWT reset

Hi all,

I'm using the HSE AB Swap function on S32K364. After downloading the application via UDS and calling HSE_ActivatePassiveBlock followed by a functional reset, the MCU resets cyclically every 10 seconds. The reset reason is MCU_HSE_SWT_RST_RESET. At this moment, HSE_CONFIG_GPR3 (0x4039c028) reads 0x81F00C1. The register bit indicates: Application read/execute is blocked from flash Block X, as HSE FW is performing flash write operation on this block. Application program and erase is also blocked for Block X

After one PE debugger attach operation, the cyclic reset stops and the system works normally. The value of HSE_CONFIG_GPR3 changes to 0xC1.

I’m stuck on this issue and would appreciate any hints or suggestions. Thanks a lot!

回复： S32K3 HSE AB Swap: 10s cyclic HSE-SWT reset

The issue has been resolved.
Root cause: The PLL was initialized in boot code before `HSE_STATUS_INIT_OK`, which caused abnormal HSE initialization and triggered the HSE watchdog, resulting in chip reset.
Moving PLL initialization to after `HSE_STATUS_INIT_OK` fixes the problem.