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HPET Timer 2, IRQ11 interrupt triggered every 20us, Baytrail E3815

Hi. I am trying to use IRQ11 for HPET and I have programmed the HPET Timer 2 comparator register to 500ms. Whenever I enable IRQ11, I get a trigger every 20us instead.

Main problem is I did not yet enable the HPET, only the IRQ11 interrupt in PIC and this happens. No matter what value I put in comparator 2, it is always 20us.

I have a hunch that since HPET shares IRQ11, this might be cause by either SERIRQ, PIRQx, or SCI.

My board is a Kontron using E3815, running under VxWorks but I am also looking at the UEFI BIOS programming side.

I am debugging now in the UEFI Shell, and assuming I have the EDK2 Workspace, which part of the UEFI programming determines the use of IRQ11?

I have attached a snapshot of my ISR using GPIO and that is where I got the measurement response of IRQ11.

I am completely at loss right now and until I hear something from Kontron support, I need to figure out the cause of this issue from UEFI perspective. Is it also doable to create an ISR in UEFI so I can replicate the problem?

Can anyone give me some direction?

Many thanks,


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Community Manager

Hello Josh0031,

Thank you for joining the Processor community.

Regarding this matter the best place to get more answers is our Embedded Community, please visit the site here: Forum: Embedded Community |Embedded Community


Amy C.