STM32U585 Systick and SVC 2 interrupts stop working on some devices

[h p]

Hello,

We are using STM32U585QII6QTR in our device that is powered via USB and batteries. We observe that some devices do not startup anymore after some time of use. It is unclear which impact causes this. Everything that can be measured outside the MCU looks as expected.
Debugging the device shows that everything is working normally, for example the bootloader checks successfully that a valid firmware is flashed by using HAL_HASHEx_SHA256_Start/Finish.
However, the Systick is not triggered and GetTick remains 0, but SysTick->VAL is counting.
Similartly, when starting the FreeRTOS Scheduler the device crashes when the SVC 2 instruction is called. The SVCHandler interrupt is not called. So, it looks like interrupts are not activated anymore.

I created a no-RTOS project with CubeMX and checked directly after HAL_Init if the Systick is triggered. On a “damaged” device there is no SysTick triggered after HAL_Init whereas on a good device it is as expected.

I attached a dump of important registers of a good and bad device.

I am looking for advice on how to find the root cause.

Many thanks for any help 

hp

[Bob S]

>  bootloader checks successfully that a valid firmware is flashed by using HAL_HASHEx_SHA256_Start/Finish

This is your custom bootloader?

Check all of your power supply connections and bypassing, NRST circuit, etc.  Can’t be of much specific help without seeing the relevant portions of the schematic.

When they fail, are they USB powered or battery powered?  What is the battery voltage?  Check power-on reset with a scope on the NRST and power rails to see if they sag.