Tickless overrun issue using FreeRTOS, nRF52

RE: Tickless overrun issue using FreeRTOS, nRF52

Anders Strand — Fri, 20 May 2016 13:01:10 GMT

This is now a know bug, see this thread.

RE: Tickless overrun issue using FreeRTOS, nRF52

Michael Dierks — Mon, 25 Apr 2016 19:30:31 GMT

I have looked at the example, I see that I am using the _cmsis version of the port. I don't see those in the FreeRTOS distribution, so I will track down when they enter the Nordic SDK. The port_cmsis_systick.c has specific code focused on dealing with TICKLESS and the use of RTC1 as the tick interrupt source. This file contains elements of low_power_tick_management_RTCC.c that you pointed to, plus some other changes.

RE: Tickless overrun issue using FreeRTOS, nRF52

www.FreeRTOS.org — Mon, 25 Apr 2016 13:32:28 GMT

Here is an example of an implementation that uses a slow (32K) up counting peripheral that you can use as a template. There are others in the download.

RE: Tickless overrun issue using FreeRTOS, nRF52

Michael Dierks — Mon, 25 Apr 2016 13:25:54 GMT

I am using the selection macros in the latest FreeRTOS port in the SDK 11. It configures the xSysTick to run from RTC1 interrupt, configured as a up-counting real-time counter, using the 32K external crystal as input. It is configured to count 1ms systick intervals, so approx 31 counts per systick.

RE: Tickless overrun issue using FreeRTOS, nRF52

www.FreeRTOS.org — Mon, 25 Apr 2016 07:31:23 GMT

Is RTC1 an up counter or a down counter? We have part specific examples for both types where the clock is 32K.

RE: Tickless overrun issue using FreeRTOS, nRF52

Michael Dierks — Mon, 25 Apr 2016 03:51:58 GMT

Long weekend. I am running the SysTick from the RTC1 on the 32K XTAL. I am looking for very low power draw, which we have mostly.

I did review the link you provided, I could not access the low-power file included in the last few responses from "rtel" on that thread. I have seen some other posts on tickless and 32K operation. I will review those more. Suppose I will need a more complex trap on where I might be going when the clock tick values get separated.

RE: Tickless overrun issue using FreeRTOS, nRF52

www.FreeRTOS.org — Thu, 21 Apr 2016 08:32:29 GMT

What is the frequency of the clock feeding the SysTick counter? There was somebody that had an issue when it was slowed right down to 32K (search for 2016 in the thread to find the start of the relevant part) - but they never reported back with the conclusion - in the thread there is also a link to a source file that shows how very slow clocks can be used, if that is indeed how your system is configured (very unusual).