topic Inquiry on Potential ISR Delay When Using Siul2_Dio_Ip_WritePin() in RTD in S32K

Inquiry on Potential ISR Delay When Using Siul2_Dio_Ip_WritePin() in RTD

malove — Fri, 30 May 2025 04:28:37 GMT

I am currently working on an S32K3-based system and using the Siul2_Dio_Ip driver from the RTD package for GPIO control.

I have observed that the `Siul2_Dio_Ip_WritePin()` function disables interrupts internally by invoking `SchM_Enter/Exit`. While I haven’t encountered any noticeable interrupt delays during actual testing, this behavior raised some questions.

Specifically, I am curious whether disabling interrupts in this context might affect real-time interrupts such as timer ISRs, potentially causing scheduling delays.

Therefore, I would like to ask:

- When `Siul2_Dio_Ip_WritePin()` is called repeatedly, does it introduce any measurable impact on ISR latency or scheduling, particularly for timer-based interrupts?

I would appreciate any clarification or reference data you can provide on this matter.

Best regards,

Re: Inquiry on Potential ISR Delay When Using Siul2_Dio_Ip_WritePin() in RTD

Julián_AragónM — Fri, 30 May 2025 17:05:05 GMT

Hi @malove,

This could be the case if a specific interrupt is invoked while the Siul2_Dio_Ip_WritePin() function is called, but I've made a simple test by calling the Pit ISR while toggling a pin with the RTD function, and without. I could not find any significant difference in between ISRs.

It is not tested specifically for ISRs, but there was a comment regarding execution time for pin toggling being affected by the scheduler module functions (See the following community post: Solved: s32k312 schM caused delay - NXP Community). You can disable the SchM implementation if you wish to remove this delay.

However, these functions are provided by NXP as stubs for AUTOSAR SchM integration. If you are targeting AUTOSAROS, these will need to be replaced by the BSW integrator with a third-party vendor (be it Vector, Elektrobit, etc.).

Best regards,
Julián