Cannot restart RTC from PPI after STOP, CLEAR tasks

RE: Cannot restart RTC from PPI after STOP, CLEAR tasks

AmbystomaLabs — Tue, 30 Jan 2018 18:56:37 GMT

The PPI doesn't have to use HF_EXT to operate. It will use the HF_INT which uses considerably less current. And the RTC xtal based clock uses very little current. A running design uses about 1.5uA overall. The RTC portion is about 0.35uA according to the blog. The LF_RC uses more since it does a periodic cal.

Also, my understanding is that it only turns on HF_INT when PPI is needed but it does not run all the time. I personally haven't had any problems using PPI with SD on nRF52. I just call power manage and everything resolves itself.

There are a lot of entries on the subject: devzone.nordicsemi.com/.../

devzone.nordicsemi.com/.../

RE: Cannot restart RTC from PPI after STOP, CLEAR tasks

SantosDevOps — Mon, 29 Jan 2018 20:54:52 GMT

Yes, in my actual solution, I kept it running. And I just clear later. I wanted to know if there was a limitation in the above approach.

RE: Cannot restart RTC from PPI after STOP, CLEAR tasks

SantosDevOps — Mon, 29 Jan 2018 20:50:51 GMT

I believe there is a possible answer was already answered. (see below). I want to be able to reset the Compare event via PPI. I am trying to stay away from the CPU doing any tasks with the HFCLK. Is this then even possible?

devzone.nordicsemi.com/.../

RE: Cannot restart RTC from PPI after STOP, CLEAR tasks

AmbystomaLabs — Mon, 29 Jan 2018 20:44:21 GMT

The way you have it written it forces clear/compare/stop and start to all happen on the same pclk cycle. I'm fairly sure this is not possible. Plus there really is no point in that. Just do the clear and forget stop/start. It is all the same logically in your code.

Once you start the timer it just keeps running. Then any cc event will just perform a clear and your gpio action, but the timer keeps running and starts over at 0x0.