Wrong RTC period unless breakpoint hits during setup

[gat]

fw1.zip

Hi,

I ran into a problem with nRF52840 based firmware development

I initialize the RTC with

Prescaler = 0

CC[0] = 0x19fd

I tried clock source synthesized from HFCLK and RC oscillator and got the same result (we don't have a LF crystal oscillator)

It should produce a period of 0x19fd/32768 = 203ms but I observe by toggling a pin in the IRQ Handler that the actual period is 112ms

If I breakpoint in my code after initializing the RTC and then let go, I get the right period 203ms

I am currently working on replacing the RTC with Timer for debug

Do you have any errata or known issue regarding RTC setup ?

How can I solve this issue ? I can provide the project if needed

Thanks,

Gabriel

[Jared]

Hi,

That sounds strange,

Can you share a minimal project so I could try to reproduce it?

regards

Jared 

[gat]

I added the project files to the original post, I tested with another value and where I was supposed to get 0x6aa/32768 = 52ms I actually get 128ms

[Jared]

Hi,

Can you try to change RTC source to RTC2 and see if you see the same issue?

regards

Jared 

[gat]

To add more information, I get the wrong period when I don't debug but I get the right period if I am in debug session

[gat]

I tried with RTC0 and RTC2 and still got the wrong period when not debugging