RTOS/CC1352R: RTC 32bits overflow

Clement Guillou

Intellectual 430 points

Part Number: CC1352R

Tool/software: TI-RTOS

Hi,

I have a question about the RTC :

I use the AONRTCCompareValueSet function from the API to set the time I need my interrupt to be triggered.

This function allows me to set events up to 65535 seconds after the start because of the nature of the parameter ( <16 sec.16 subsec> )

How am I supposed to handle this overflow ? How do I set events later than 65535 secondes ?

Best regards,

Clement

over 7 years ago

0 IUsedToBeARealPerson (M-W) over 7 years ago

TI__Guru 58425 points

Hi Clement,

You would have to handle this overflow as an event. If you need an interrupt at say 70000 s from now, you would have to "split" this duration into multiple events.

0 IUsedToBeARealPerson (M-W) over 7 years ago in reply to IUsedToBeARealPerson (M-W)

TI__Guru 58425 points

Hi Clement,

Could you elaborate on why this was not an answer to your question? Is there another answers you are looking for?

0 Clement Guillou over 7 years ago in reply to IUsedToBeARealPerson (M-W)

Intellectual 430 points

Hi M-W,

Yes, sorry, I started to answer and my attention was drawn away...

I wanted to ask some precisions about this "spliting" of events. I don't fully understand what you meant by that...

Can you give me an example to set the trigger of the RTC at this 70000 secondes ? Do I set it at 4465 (70000 - 65535) ?

Thanks for your help,

Clement

0 IUsedToBeARealPerson (M-W) over 7 years ago in reply to Clement Guillou

TI__Guru 58425 points

Hi Clement,

The precision would not be any different depending on your implementation. As an example, say you need a 70000s interrupt but you are limited to 60000s in teh compare register (let's use this instead of 65535 to make the math easy). In this case, your "total" system time might be 100000s, you you actually want an interrupt when we hit 170000s.

As we can not configure this using our 60000s compare register, we could (for example) instead configure the RTC to expire at 135000 (35000 in terms of the compare register). During this interrupt (let's call it "overflow") you then reconfigure the compare register to expire at 10000s (the counter will wrap around 60000 and then count up to 10000), this second interrupt should now be at 170000s.

0 Clement Guillou over 7 years ago in reply to IUsedToBeARealPerson (M-W)

Intellectual 430 points

Hi M-W

So, if I understand correctly, if I set an event to trigger at a time that is preceding the time right now (which I get with AONRTCCurrentCompareValueGet), it will actually trigger in the next cycle, after this overflow ?

For instance, let's say i'm at 59990 (with the 60000 overflow mentioned before), if I set the compare value to 10, it will trigger in 20 secondes ? Is that it ?

Best Regards,
Clement

0 IUsedToBeARealPerson (M-W) over 7 years ago in reply to Clement Guillou

TI__Guru 58425 points

Hi Clement,

Yes, that it is :)

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RTOS/CC1352R: RTC 32bits overflow