AM5716: TI-RTOS IPC and HWI_disable()

Marco Tinner52

Part Number: AM5716

Dear TI Support Team

We are using TI-RTOS on a AM571x in our Product. On the C66 part of the processor we are running a controller in a HWI. The HWI is triggered by a EPWM. When we now toggle a GPIO inside the HWI and measure the entry time from the HWI against the PWM we can see a jitter up to 2us. After some investigation we found out that in the IPC part of the TI-RTOS HWI_disable() is called and sometimes blocks the HWI. I also found this post: https://e2e.ti.com/support/legacy_forums/embedded/tirtos/f/355/t/408949 which describes a similar issue.

My question is now if there is any way to prevent the IPC from disabling the HWI? (A very short period would be ok)

Is it possible to write our own ipc code and use it inside the RTOS?

Any other ideas how to resolve this issue?

We are using ipc version: 3.50.3.05 and TransportShmNotifySetup

Thanks a lot.

Kind regards

Marco

over 5 years ago

0 Michael Erdahl over 5 years ago

TI__Genius 13505 points

Hi Marco,

Apologies for the long delay! In your situation, are you wanting the EPWM HWI to preempt the IPC HWI (i.e., nested interrupts)? If yes, this thread may offer some help (it's old, but applies to C66 and IPC3.x): https://e2e.ti.com/support/legacy_forums/embedded/tirtos/f/355/t/447077?How-IPC-s-HWI-configured-especially-the-priority-

Regards,
Mike

0 Marco Tinner52 over 5 years ago in reply to Michael Erdahl

Prodigy 210 points

Dear Mike

No the interrupt is not preempted. The problem is that in the IPC Code hwi_disable() is called. HWIs are disabled for to long so the EPWM HWI has a huge jitter sometimes up to 3us. With our control loop runing around 20us this is not acceptable. Is there a way to prevent the IPC Code from calling hwi_disable()?

Kind regards
Marco

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AM5716: TI-RTOS IPC and HWI_disable()