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| .. | ||
| src | ||
| CMakeLists.txt | ||
| Kconfig | ||
| README.rst | ||
| app.overlay | ||
| prj.conf | ||
| sample.yaml | ||
README.rst
.. zephyr:code-sample:: nrf_clock_skew :name: nRF5x Clock Skew Measure the skew between the high-frequency and low-frequency clocks. Overview ******** This sample uses the API for correlating time sources to measure the skew between HFCLK (used for the CPU) and LFCLK (used for system time). It also shows how to use this skew to correct durations measured in the LFCLK domain to durations in the HFCLK domain. The ``CONFIG_APP_ENABLE_HFXO`` Kconfig option can be select to configure the high frequency clock to use a crystal oscillator rather than the default RC oscillator. (Capabilities like Bluetooth that require an accurate high-frequency clock generally enable this source automatically.) The relative error is significantly lower when HFXO is enabled. Requirements ************ This application uses any nRF51 DK or nRF52 DK board for the demo. Building, Flashing and Running ****************************** .. zephyr-app-commands:: :zephyr-app: samples/boards/nordic/clock_skew :board: nrf52dk/nrf52832 :goals: build flash :compact: Running: Sample Output ============= .. code-block:: console *** Booting Zephyr OS build v2.5.0-rc3-94-g06a4b650467b *** Power-up clocks: LFCLK[ON]: Running LFXO ; HFCLK[OFF]: Running HFINT Start TIMER_0: 0 Timer-running clocks: LFCLK[ON]: Running LFXO ; HFCLK[OFF]: Running HFINT Checking TIMER_0 at 16000000 Hz against ticks at 32768 Hz Timer wraps every 268 s Ty Latest Base Span Err HF 00:00:00.015666 LF 00:00:00.404937 Started sync: 0 Ty Latest Base Span Err HF 00:00:09.978436 00:00:00.015666 00:00:09.962769 LF 00:00:10.414520 00:00:00.404937 00:00:10.009582 00:00:00.046813 RHF 00:00:09.978435 -00:00:00.000000 Skew 0.995323 ; err 4676818 ppb Ty Latest Base Span Err HF 00:00:19.959136 00:00:00.015666 00:00:19.943469 LF 00:00:20.441589 00:00:00.404937 00:00:20.036651 00:00:00.093182 RHF 00:00:19.959117 -00:00:00.000018 Skew 0.995349 ; err 4650592 ppb Ty Latest Base Span Err HF 00:00:29.937181 00:00:00.015666 00:00:29.921514 LF 00:00:30.468627 00:00:00.404937 00:00:30.063690 00:00:00.142176 RHF 00:00:29.937175 -00:00:00.000005 Skew 0.995271 ; err 4729151 ppb Ty Latest Base Span Err HF 00:00:39.917347 00:00:00.015666 00:00:39.901680 LF 00:00:40.495666 00:00:00.404937 00:00:40.090728 00:00:00.189048 RHF 00:00:39.917339 -00:00:00.000008 Skew 0.995284 ; err 4715502 ppb Ty Latest Base Span Err HF 00:00:49.899493 00:00:00.015666 00:00:49.883826 LF 00:00:50.522674 00:00:00.404937 00:00:50.117736 00:00:00.233910 RHF 00:00:49.899486 -00:00:00.000007 Skew 0.995333 ; err 4667222 ppb Ty Latest Base Span Err HF 00:00:59.878166 00:00:00.015666 00:00:59.862499 LF 00:01:00.549713 00:00:00.404937 00:01:00.144775 00:00:00.282276 RHF 00:00:59.878154 -00:00:00.000011 Skew 0.995307 ; err 4693269 ppb ... Ty Latest Base Span Err HF 00:02:59.654855 00:00:00.015666 00:02:59.639188 LF 00:03:00.873901 00:00:00.404937 00:03:00.468963 00:00:00.829775 RHF 00:02:59.654857 00:00:00.000001 Skew 0.995402 ; err 4597902 ppb ... Ty Latest Base Span Err HF 00:04:59.410593 00:00:00.015666 00:04:59.394926 LF 00:05:01.198181 00:00:00.404937 00:05:00.793243 00:00:01.398317 RHF 00:04:59.410594 00:00:00.000001 Skew 0.995351 ; err 4648745 ppb ... Ty Latest Base Span Err HF 00:09:58.829511 00:00:00.015666 00:09:58.813845 LF 00:10:02.008911 00:00:00.404937 00:10:01.603973 00:00:02.790128 RHF 00:09:58.829509 -00:00:00.000002 Skew 0.995362 ; err 4637837 ppb ... Ty Latest Base Span Err HF 00:29:56.607589 00:00:00.015666 00:29:56.591923 LF 00:30:05.250732 00:00:00.404937 00:30:04.845794 00:00:08.253871 RHF 00:29:56.607585 -00:00:00.000004 Skew 0.995427 ; err 4573166 ppb ... Ty Latest Base Span Err HF 00:59:43.781443 00:00:00.015666 00:59:43.765776 LF 01:00:00.085113 00:00:00.404937 00:59:59.680175 00:00:15.914399 RHF 00:59:43.781535 00:00:00.000092 Skew 0.995579 ; err 4421055 ppb ... Ty Latest Base Span Err HF 01:59:37.666395 00:00:00.015666 01:59:37.650728 LF 02:00:09.810913 00:00:00.404937 02:00:09.405975 00:00:31.755247 RHF 01:59:37.666057 -00:00:00.000338 Skew 0.995595 ; err 4404723 ppb ... Ty Latest Base Span Err HF 05:58:33.905236 00:00:00.015666 05:58:33.889570 LF 06:00:08.604980 00:00:00.404937 06:00:08.200042 00:01:34.310472 RHF 05:58:33.904338 -00:00:00.000898 .. Skew 0.995635 ; err 4364550 ppb Ty Latest Base Span Err HF 11:56:59.503922 00:00:00.015666 11:56:59.488255 LF 12:00:06.793182 00:00:00.404937 12:00:06.388244 00:03:06.899989 RHF 11:56:59.503948 00:00:00.000025 Skew 0.995674 ; err 4325747 ppb